Sunday, May 22, 2011

The Light Show

If it starts to look like a Christmas tree, you could have problems

On just about every vehicle out there, the moment you first turn the key on, but before you actually crank the engine, a multitude of lights will light up the instrument cluster like a Christmas tree. As soon as the engine cranks and starts many of the lights shut off right away and the rest will shut off within a few seconds. If one of these lights stays on then you may have a problem. Knowing what the problem is and how severe the problem might be is a task left to professionals, but if you know what each one of these lights refers too, and you understand the various ways in which they may illuminate, then it will help you to know if you can ignore it for a day or two until you have a chance to take it into the shop, or if it means that you must pull over right away before you do major damage to some system on the vehicle.

Sometimes these lights are called “dummy lights” this name comes from the idea that when the light comes on it is almost as if it is saying, “you’ve got a problem dummy, pull over now.” Knowing each MIL (malfunction indicator lamp) that applies to your vehicle really is a must.

Check Engine Light

This light really doesn’t have much to do with the engine itself and has more to do with the engine control systems and the emissions control systems. Sometimes the light might say “service engine soon” or sometimes it might just be an outline of an engine and not have any words around the light at all. Getting rid of words is something that has become more common recently in vehicle controls and instrumentation because it means that the light can be understood regardless of the language of the driver.

When the Check Engine MIL illuminates it means that a failure in the engine controls, or the emissions controls, has occurred that will cause an increase in the emissions from the vehicle. This is bad for obvious reasons, but even if you don’t really care about the emissions from your vehicle, it also usually means that the vehicle is less efficient and you may also notice a loss of power or reduced fuel economy.

When the light illuminates the computer that controls the engine will also store a diagnostic trouble code that relates to the failure. This code can be read from the computer using a special scan tool the will communicate with the computer to extract all sorts of information related to the code and the failure. This code is a clue for the technician to use to determine where the exact failure has occurred. Some people are under the impression that the technician can hook up the car to some kind of magical machine, and the machine will tell them everything that’s wrong. This is not true. The scan tool provides clues, but it takes a good diagnostician to piece the clues together.

This is why it costs so much money just to have a technician read the codes and do a bit of diagnostic work. If you ever go to a repair shop or any other place, e.g. parts store, quick lube, and the like, and they say that they will tell you why the light is on for free, remember that you get what you pay for. If they really aren’t going to charge you to hook up their scan tool then they really aren’t going to give you much useful information. In the case of parts store, they will be more than happy to sell you a part on the off chance that it might fix the vehicle. Of course if you go and put that part on your car and it doesn’t fix it, don’t count on the parts store refunding your money for the part.

If the check engine light comes on it almost never means that the vehicle must be pulled over to the side of the road immediately, it usually means that the system ought to be checked out as soon as possible. If the light comes on but the vehicle seems to be running just fine then there is no big hurry to take any action. Just make sure to schedule an appointment with your mechanic as soon as possible. If the MIL comes on and you notice a difference in the way the car is running such as, a loss of power, stumble or hesitation, vibration or excessive noise, then the situation is more urgent. Drive the car home or to the shop as soon as you can and don’t drive it anywhere else.

If the light illuminates and blinks off and on rapidly, pull your car over and shut it off as soon as you can get to a safe place. The blinking light is meant to instill a greater sense of urgency to get the driver to take the appropriate action. The blinking light also indicates what is referred to as a type A misfire. This is when at least one of the cylinders of the engine stops firing altogether. This is something that can destroy the catalytic converter. The “cat,” as it is commonly called, is an emissions control device located in the exhaust system. When the cat is destroyed it may cost over $1000 just to fix it, let alone the thing that caused the misfire which ruined the cat. This is why the blinking check engine light should never be ignored.

When the check engine light comes on it means something is broken and must be fixed. Some people say that the light on the car just comes on sometimes and shuts itself off later and that this is normal and no big deal. Well it may be normal and the driver might think that it’s no big deal but it still means that something is broken.

Brake Light

The brake warning light can take on many different forms. Sometimes the word “brake” is used all by itself and sometimes there will be some kind of symbol used with brake, or sometimes it’s just some kind of symbol. The brake warning light will usually indicate any one of three and sometimes four different things. The different possibilities will ultimately depend on the make and model of the vehicle in question.

When the parking brake is applied the brake light will come on and stay on until the parking brake is released. This is easy to understand and usually no big deal to figure out, but some people might forget and they will actually drive their vehicle several miles before they realize what is going on.
The brake light could like anyone of these or all of them together.
The second thing that the brake light comes on for is low brake fluid level in the master cylinder. This is really easy to check. Simply remove the cap on the reservoir look inside. If the reservoir is translucent, just look at the level through the plastic sides. High and low levels are indicated on the side of the reservoir. If the fluid is low then don’t just add fluid and call it good. Many times when the fluid level falls to a low level it is an indication of worn out brake linings. As the linings in the disc brakes wear, the fluid flows into a larger and larger space behind the caliper piston. This will cause the level in the reservoir to go down. When the pads are replaced and the calipers reset, the fluid is pushed back into the reservoir.

The third thing that causes the brake light to come on is a pressure imbalance in the brake hydraulic system. Usually if the light comes on for this reason, the brake pedal will sink much lower and it will take longer for the vehicle to stop. All cars actually use two separate hydraulic systems to apply the brakes. One system applies the brakes on two wheels, and the other system applies the brakes on the other two wheels. If there is a leak in one of the systems, the pressure in the other system will activate a switch that will cause the light to come on. To repair this kind of failure a professional may be needed and it is obviously not safe to drive the vehicle.

The last thing that will cause the brake light to come on only applies to some cars, usually European cars. This last thing is worn out brake pads. The brake pads on most BMW, Mercedes, and Volkswagen vehicles have a sensor in them. This sensor is tripped when the pads wear thin and it will cause the light to come on. Sometimes the pad wear light may be different from the regular brake warning light.

Battery Light

The battery light is sometimes called the charging system indicator. Either way, the light itself is usually shaped like a battery with a plus and a minus symbol on it. This light will come on when the voltage in the battery or charging system is too low. Many vehicles with a voltmeter in the cluster will also still have a battery light. When the key is turned to the on position but the engine is not started, this light comes on because it is sensing battery voltage only which, without the engine running, will always be lower then what the light and its control systems like to see. When the engine is started the alternator begins to turn and do its job. This will cause the voltage in the battery and charging system to go to about 14 volts if all is functioning correctly. This voltage will cause the battery light to turn off.

Battery light
If this light comes on and stays on while you are driving down the road, it means that the alternator might not be working, and there is a possibility that the vehicle could stall. When the alternator isn’t working, things like the fuel pump and ignition system are drawing all of the power they need directly from the battery, and the battery isn’t getting charged. Eventually the battery will go dead and the engine will die. This won’t hurt the car but it will leave you stranded. Once the engine stalls it isn’t going to even want to crank. If you can drive home or to the shop before the car dies, it is okay to do so, just make sure that you conserve electrical power in the vehicle by turning off all electrical accessories. If you are driving at night then don’t even try and drive the vehicle. Just pull over safely and call a tow truck. The head lights draw so much power that you probably won’t make it very far and it’s not safe to drive with the headlights off.

Oil Light

This is a light that should not be ignored whatsoever. The oil light comes on when the key is first turned on and shuts off a few seconds after the engine starts. This light comes on when oil pressure drops to zero. This is why it’s on when you first turn the key on. Without the engine running there is never any oil pressure. Vehicles that have an oil pressure gauge will always still use an oil pressure light.

Oil pressure light
When this light comes on you must pull over IMMIDIATELY and turn the engine off. This does not indicate low oil level, or that the oil needs to be changed, or that you need to check it. The time for checking the oil is past, this means pull over dummy or you will blow up your engine. Way too many people who neglect the maintenance on their car also turn out to be the same people that keep driving to the next freeway exit when they see this light, but of course it is too late. Once this light comes on solid you have a few seconds before damage occurs and maybe a minute or two, depending on the load on the engine, before the engine comes undone.
Oil level light

Some vehicles have a “Low Oil” light but this is something totally different. If the low oil light comes on it means that you need to add some oil, but you are not really going to hurt anything by driving to a place where it is safe to pull over and have a look. Most cars don’t have a low oil light so don’t assume that yours does. This is the kind of light that you will never see unless your oil level is actually low.

TPMS Light

The Tire Pressure Monitoring System (TPMS) MIL is something that is relatively new. Because of the Firestone Tire/Ford Explorer, scandal of the last decade, Congress came up with a mandate that said that every vehicle sold in the US should have some kind of tire pressure monitoring system installed from the factory starting with the 2008 model year. Many manufacturers started putting these systems on long before the mandate.
See this light, check your tire pressure

The system consists of a tire pressure sensor located in each wheel assembly. The reading taken by each sensor is transmitted wirelessly to a receiver which sends the signal to a processor that monitors the pressure and temperature of each tire. When the computer senses that a tire is too low, it will illuminate the TPMS light. In order to make the light turn off, the tire must inflated to the proper pressure. Some systems will turn the light off as soon as the pressure is set to specification, and some must have the pressure set and then be driven several feet before the light will turn off.

When this light comes on check your tire pressure. Tires that are under inflated can be dangerous because the tires can get very hot and could fail. These systems will usually not turn the light on for over inflation, but over inflation can be dangerous as well. Many systems will not just turn on the TPMS light but they also have an information display that will tell you which tire is low.
A tire pressure sensor mounted to the inside of a rim.
Because TPMS is a computer controlled system, it is capable of some self diagnosis and as such it may illuminate the TPMS MIL if there is a failure in the system. On most vehicles when there is a failure in the monitoring system and not necessarily a low tire, the TPMS light will come on and blink for the first few minutes after the engine is started. This means that a trouble code is stored and a scan tool is needed to extract the code from the control unit. The sensors in the wheels are all battery powered and they only last so long. When one of the sensor batteries fails it will cause a trouble code to set and the TPMS light to come on. Most TPMS systems also have a reset button that might need to be pressed if all of the tires are set to the proper pressure and the light will not turn off. This might happen as the seasons change because of the way that temperature and pressure are related.

ABS Light

ABS stands for Anti-lock Braking System. The ABS light might say ABS, it might have the brake symbol with ABS in the middle, or it might say “Anti-Lock.” ABS is a system integrated into the vehicle braking system that prevents the brakes from locking up, causing the car to skid and actually increasing the stopping distance. This system uses speed sensors at each wheel that send a signal to a computer indicating the rate of deceleration for the wheel in its rotation. If the wheel stops rotating, the computer can pump the brakes to that wheel alone and prevent the wheel from locking up.

Because this is a computer controlled system like everything else on the car, it is capable of monitoring its own systems and alerting the driver if a problem is found. Once again the computer stores a trouble code that indicates what might be going on with the system. Other systems such as traction control and anti-skid control are very much related to the ABS system. These two systems might have their own MILs that may illuminate together with the ABS light if there is a failure that affects the operation of any or all of these systems. If any of these lights are on it might also mean that the corresponding system will not work, or might not work very well. Most of the time, the brake warning indicator comes on with the ABS light.

SRS Light

The Supplemental Restraint System usually refers to the airbags on the vehicle but with modern restraint systems it could also refer to the seats or the seat belts since they have passive restraint systems integrated into them as well. The SRS light might say SRS, Restraints, or have a picture of an airbag inflated in front of the figure of a person sitting in the car seat. Computer controlled system, trouble code, airbag might not work, you can see a pattern forming here. The SRS system runs a system check every time the key is turned on. The light will stay on during the check and will shut off if no problems are found. This light might not shut off for 5 to 10 seconds after the vehicle is started. Some SRS lights will blink for several seconds during the check and if a problem is found could continue to blink for a minute or two and then stay on permanently.

Coolant Light

Coolant temperature light
Used on vehicles that lack a temperature gauge. The light comes on when the engine temperature gets too hot. Engine should be shut off to prevent damage to internals. Some vehicles have a coolant level light. This might look similar but indicates low coolant in the radiator or the coolant expansion tank.

Maintenance Required Light

Sometimes this will be indicated with words, sometimes it will be indicated with a small wrench symbol. This is a light that comes on to indicate an interval of mileage or time, and indicates that some kind of vehicle service is required. This light can usually be reset without any special tool, but the procedure might not be listed in the owner’s manual. Some vehicles have a maintenance light that says “Service Vehicle Soon,” this should not be confused with the Service Engine Soon light that was mentioned above.

Other Lights

Many other lights can be found on many different types of vehicles. If you are not sure what lights your vehicle has or what those lights mean, check your owner’s manual. The last thing you want on a road trip is an unknown light coming on. You won’t know what it means and you won’t know whether you can continue on your way, or stay put until you get it fixed. No matter what, never forget that lights mean things. Anytime you see one there is a reason that it came on.

Sunday, May 15, 2011

ATF Doesn’t Stand for Alcohol, Tobacco, and Firearms

Automatic Transmission Fluid, The other oil change

After oil changes and cooling system flushes the fluid that is probably the next most important, if you have an automatic transmission, is the automatic transmission fluid. This is that magical red fluid that your transmission is completely incapable of functioning without. The engine will still run without oil and coolant, the steering system will still steer without power steering fluid, but the transmission will quit working altogether if it looses only a few quarts of ATF.

What is it

Automatic Transmission fluid is essentially a specialized hydraulic fluid. Like all other hydraulic fluids it’s primary task is to transmit force. The automatic transmission contains numerous hydraulic circuits that channel fluid force in order to activate hydraulic pistons and servos. These pistons and servos are responsible for actuating various clutches and other braking mechanisms in order to make the transmission function. ATF must also lubricate all of these mechanical parts that are constantly rubbing and touching and heating up against each other.

Clean ATF is usually a nice red color
This fluid is very heavily abused inside the transmission but it contains all sorts of additives to help it do its job and last a long time. Some of the additives include friction modifiers, detergents, antioxidants, dispersants, anti-foaming agents, and others. All of these things give ATF its unique properties. The red color that you usually see in ATF is actually a dye that is primarily added to help in differentiating between engine oil and ATF by sight. This fluid is so good at what it does that many manufacturers also use it for power steering fluid. If you ever get your hands extremely soiled with grease and grime, just scrub them lightly with some clean ATF and it will not only clean the tough grime out from under your finger nails but it will leave your skin feeling soft. The additives in ATF are meant to keep the inside of the transmission clean and those same additives work on your hands as well.

Check it

In the past every vehicle had a second dipstick, other that the engine oil dipstick, which was used for checking the level of the ATF. For vehicles that are still equipped with such, checking the ATF is very easy. Most cars require that the engine be running with the transmission in park. Some require that the transmission be in neutral. Honda trucks and cars with automatics require that the engine be off. If you are not sure what your vehicle requires, you can sometimes find directions on the dipstick itself. If that doesn’t work then consult the owner’s manual.

Most cars also require that the engine and transmission be warmed up in order to get the most accurate reading. The reason for this is that ATF expands quite a bit as it warms up. One might believe the fluid level to be low when in reality the fluid is just cold. Many manufacturers put separate marks on the dipstick that are used if the fluid is cold, but what if the fluid is somewhere between cold and warm? This is why it’s just best to check it with the fluid warmed up.

The goal when adding or checking fluid is to make sure that the fluid level is between the two marks that are found on the dipstick. If the level is below the lower mark then some fluid must be added, but if the level is between the marks, then that is satisfactory, and no more fluid is required. If fluid needs to be added then usually it must be poured down the dipstick tube. These dipstick tubes that double as a filler tube are usually wide enough to put the end of a funnel into them. If the dipstick tube is too narrow to fit a normal sized funnel into the end of it, then there is likely a filler plug somewhere else.
A tranny pan with a drain plug in it, the fill plug can be seen
in the housing above the pan.
Besides looking at the level the condition of the fluid can also be examined. If the fluid contains very tiny black particles that rub off on your oil rag or paper towel this is normal, but can it can indicate that the fluid needs to be serviced. These small black particles are bits of clutch pack material that are suspended in the fluid. This is a sign of normal wear and tear but if the particles become excessive, or if the particles are metallic looking; this could indicate some major problems. The last thing you can do that can help determine fluid condition is give it a sniff. Worn out fluid will have a definite burnt smell to it and fluid from a transmission that has completely failed smells downright disgusting.

Many new cars do not have dipsticks. On these vehicles the fluid must be checked by climbing underneath the car and removing some kind of plug from the side of the transmission in order to see the fluid level. Some of these newer cars will still have the dipstick tube but no dipstick in it. On top of the tube you will find a plug that says in order to check the fluid level you have to take to take the car to the dealership service department. Once there, the technicians can check it with a special tool that looks just like a dipstick. This seems silly and it probably is. The reason for no dipstick is that the car builders want you to believe that you don’t need to check or maintain the fluid. Many of them actually say that the fluid they use is good for the life of the vehicle. This is not exactly true but with modern synthetic fluids, the fluid is at least good for the warranty period and that’s good enough for them. Some cars have a sensor in the transmission that will monitor fluid, and the level can be checked via the information computer located in the instrument cluster.

ATF Doesn’t Get Consumed

If you check your ATF regularly and find that you always have to add a little every few months then you have a problem. Transmission fluid does not get consumed as it is performing its job. Engines will naturally burn a bit of oil every time they are running which will cause the oil level to go down. Transmissions don’t burn fluid. If the fluid level drops it is most likely due to an external leak. Just because you don’t see puddle in the driveway doesn’t mean that there are no leaks. The only other place the ATF could go is into the coolant. The transmission fluid is pumped up to the radiator where it passes through a cooler that is located in the radiator, surrounded by coolant. If this cooler leaks it may allow transmission fluid to leak into the cooling system. This is very rare. Running the transmission low on fluid can be very damaging to the transmission. If the fluid is going away, find out where it is leaking and get it fixed.

Service Needed

Most of the time you can never go wrong following the manufacturer’s service recommendations, but when it come to ATF service there are a few things to consider. The thing that happens to just about every fluid in any automotive system is oxidation. When ATF becomes oxidized it is no longer able to perform its duties in an effective manner because it is no longer just pure ATF, it is some kind of oxide thereof. Think of the body panels on an old car. The rust that you see on an old car is oxidation of the metals that comprise that body panel. This oxidized metal is no longer good for maintaining the structural integrity of the car’s body panels. Oxidized ATF is the same way.

As mentioned previously, some cars supposedly come with ATF that is good for life. If this isn’t true then how can the ATF be serviced, and how often? The fluid can still be drained in the same ways that it is on older cars. There is always either a drain plug in the bottom of the transmission, or the pan that holds the fluid can be removed. Because these cars come with high quality synthetic fluid, this same fluid should be used when servicing such cars. The interval for this service will be fairly long, but it probably shouldn’t be ignored. If the supposed lifetime fluid were service every 80,000 to 100,000 miles, this would probably suffice.
Transmission fluid drain plug in the pan. Above that the spin-on type
fluid filter can be seen.
All of the regular cars out there that still have transmissions with a service interval usually need to be serviced about every 30,000 to 60,000 miles. Sometimes the service might just involve a drain and fill of the transmission, some require the replacement of a spin-on filter on the side of the transmission that looks like an engine oil filter, and some require that the pan on the bottom of the transmission be removed, and the filter screen behind it replaced. In reality, removing the pan and replacing the filter screen is really not that necessary. The screen should never get plugged by normal wear and tear, and if it does get plugged to the point where fluid flow is restricted, the transmission is probably on its way out anyway. 
The filter screen behind the transmission pan
In some instances a transmission flush may be appropriate. This involves hooking up the transmission fluid lines to a fancy machine that will remove all of the old fluid and replace it with new fluid. This is good for getting all of the old fluid out. When the transmission is drained through regular means you can usually only get about 4 to 6 quarts out, which isn’t that much considering the transmission actually holds upwards of 10 to 12 quarts. If the ATF is serviced as often as it should be, a flush isn’t really necessary, but if the fluid has long been neglected, or the transmission seems to shift a little harshly then a flush might be a good idea.

The last consideration when either adding fluid or servicing the fluid is what type of fluid to use. Like so many other things on the car, this has become complicated by the fact that every auto company seems to use some kind of proprietary fluid. Regular common ATF is usually referred to as Dexron/Mercon. The Dexron name came from GM way back in the day, and the Mercon name comes from Ford. Recently with the advent of synthetic ATFs these two names are not seen together anymore. Instead we have Dexron VI and Mercon V, which it’s safe to assume are not really the same thing. The biggest thing to remember is that if the transmission was designed for a nonsynthetic ATF, then Dex/Merc III is probably fine. If it was designed for synthetic, then use the Dexron VI or the Mercon V. Many cars that are neither GM products nor Ford products will use Dexron/Mercon. Honda automatics however, are not at all like regular automatics so they should use what is known as ATF Z-1. If this is too confusing then just go to the dealership parts department to get your fluid and then you know that it will be the right stuff. If you don’t use the proper fluid it probably won’t hurt your transmission, but the shifts might not feel as smooth as they should.

Sunday, May 8, 2011

Forced Air and the Future

Nothing like a little mouth to mouth to get you breathing deep

Forced induction. These two words together can make a grown man salivate in a way that not many other things can. What this term refers to, in relation to the function of the automobile, is any device or method that forces more air into the intake of an engine. Forcing more air into the engine means that more fuel can be burned when needed, and more power can be produced by the engine when needed.

Many people think that the force that causes the air to flow into the engine is the suction created by the piston moving down in the cylinder with the intake valve open. This is not true. The piston moving down only creates a vacuum, which is an area of negative pressure. Once this void is created something will rush in to fill it, and that something is air. The motivation for the air is atmospheric pressure. This is one of the reasons that the average car or truck will produce more power at low elevation versus high elevation.

At sea level normal air pressure is 14.7 psi. This means that a column of air at sea level measuring one square inch, reaching all the way up through the atmosphere, weighs 14.7 pounds. The further up from sea level that you measure the weight of the column, the less it will weigh. In Denver, CO the column of air will weigh about 12.2 pounds. In Leadville, CO which is a town over 10,000 ft. high in the Rockies, the column will weigh 10.3 pounds. Because of this decrease in pressure, a car that is operating at this elevation will not be as powerful. The other thing that goes along with this is the fact that at higher elevation the oxygen content of the air is lower.

In the early days of modern aviation the service ceiling of the average aircraft was limited by this same fact. If an airplane flew too high it would loose power. Forced induction systems first showed up on aircraft during WWI. This allowed the planes to fly much higher than they otherwise could have. Like so many other bits of technology that improved aircraft, it was only a matter of time before some mechanic said, “I think I should try bolting one of these things on my car.”


Forced induction systems can be divided into two distinct groups, turbochargers and superchargers. In reality a turbocharger is a type of supercharger but usually the two do not get lumped together into the same category because they don’t operate the same way, even though they essentially accomplish the same task.

A supercharger
The supercharger is a belt driven compressor that forces large amounts of air into the intake manifold. A belt similar to the type that turns accessories such as the alternator or the A/C compressor will be used to turn a set of screws within a housing, that are in mesh with each other, or some kind of similar device. The amount of pressure that a supercharger will build varies from one engine to another but it is usually somewhere between 8 and 15 psi. Since the supercharger is turning anytime the engine is running it can build boost very quikly.

A basic turbocharger setup.

The turbo charger compresses air and forces that compressed air into the intake manifold but it is driven by exhaust gasses exiting the engine through the exhaust ports. These gasses spin a wheel that is attached to a shaft. On the other end of the shaft is another wheel that compresses the incoming air. Turbochargers will produce boost pressure in the same neighborhood as superchargers do but they do not drag on the engine because they are not driven by the crankshaft. This sounds like a great advantage for the turbo but there is also a problem. This problem is reefed to as turbo lag. This is used to describe the brief period of time between initial throttle application and the point at which the turbo is spinning fast enough to create boost. Superchargers do not suffer from this kind of lag.

The Future

In the past, any vehicle with a forced induction system was considered high performance, or at least higher performance then the equivalent vehicle in a naturally aspirated form. A forced induction system fitted to an engine that could already be considered high performance makes for a real screamer. Top Fuel dragsters have massive superchargers breathing air into massive engines. These cars can run a quarter of a mile in about 4 seconds. A tremendous amount of air is forced into the engine in order to burn a tremendous amount of fuel. In the real world we only need lots of power for brief moments here and there. Like when we are getting on the freeway, passing a slower vehicle on a two lane road, or when we are trying to beat another car to a prime parking spot at the mall. The rest of the time we only need a small amount of power to get around.

With all of the talk about new automotive technologies that are very advanced and becoming more widely available, the one that does not get as much attention is the new turbocharged engines, and the high levels of efficiency that they obtain. They probably don’t get a lot of attention because the technology is really not that new. This instance just sees the technology applied in a slightly different way. With the proper application of a turbocharger, an engine’s output and efficiency can be raised enough to make the engine seem like something much bigger than it really is. 4 cylinder engines can easily have the power of a V6 and a V6 can have the power of a V8. This can happen without sacrificing fuel economy because small displacement engines are used, with variable geometry turbos, and the only time the engine needs to put out big power is under heavy load. The rest of the time that the engine is running, the smaller size helps it get better fuel economy.

2011 Chevrolet Cruze
The Ford Ecoboost engine is a great example of an engine that puts out tremendous power when needed but still gets great fuel economy. The V6 Ecoboost engine that is available in a few different models puts out somewhere between 300 and 360 HP and gets about 20 to 25 mpg. The Chevrolet Cruze also uses similar technology. The 1.4 liter turbocharged engine in the Cruze, gets about 40 mpg and delivers 138 HP. This is pretty close to what some hybrids of the same size achieve but at literally half the price.
2011 Ford Taurus
Why isn’t everyone using these kind of forced induction systems on all of the vehicles they build? The biggest reason is cost. While a small turbo setup might be much cheaper then a hybrid drivetrain, it still costs more than an engine that doesn’t have a turbo. If gas prices keep going up, which they will, all of the manufacturers will have to adapt some way or another, because the public will demand more efficient vehicles that get better gas mileage. Maybe smaller engines with forced induction systems will be the best answer for all of them.

With the current spike in gas prices sales of SUVs and big trucks are down, and the sales of smaller more fuel efficient vehicles are up. The Ecoboost F150 is selling much better than Ford expected. This is a big truck that usually appeals to people who would never buy anything with fewer than 8 cylinders. When the cost to fill your tank goes through the roof, you change the way you think, and then suddenly a V6 powered pickup truck doesn’t seem so bad. Not only does it not seem bad, in all reality it isn’t.

Sunday, May 1, 2011

Keeping Your Cool

What color do you need to stay cool?

Green used to be the standard. Then orange became a common color for some cars. Yellow is now very common, but other colors like blue, purple, red, and pink? All of these colors are now common enough among the various makes driving around the streets today. These are the colors of the different coolants in the radiators of modern automobiles. What happened to green and what is the meaning of all of these new colors?

All the pretty colors
Coolant, or anti-freeze as it is also called, is the fluid that is found in the engine cooling system of every vehicle that is liquid cooled. The majority of engine coolants are made from a chemical known as ethylene glycol. This chemical is mixed with water in order to make the coolant that is found in the engine. Ethylene glycol is used because it does a few different things to benefit the cooling system.

The first thing it does is raise the boiling point of the coolant mixture. The engine typically runs somewhere between 190° and 220° f. Water boils at 212° so something must be added to water to increase the boiling point. If coolant were to boil, it would lead to pockets of air in the coolant which could not be compressed by the water pump. Excess heat in the engine could not be removed, and the engine would get so hot it would melt down into one solid lump of metal alloy (not really but it might as well). These pockets of gas also lead to a highly damaging form of corrosion known as cavitation. The cooling system will also operate under pressure which further increases the boiling point and prevents the formation of vapor bubbles in the system. This is the coolant part of coolant.

Ethylene glycol will also lower the freezing point of the coolant mixture. If the coolant freezes then it will not flow once the engine is started and the engine will then overheat. If the coolant freezes inside of the engine it may also lead to engine damage because of the expansion that occurs when water freezes. This is the antifreeze part of antifreeze.

The last thing that ethylene glycol does is protect the differing metals that are used to construct the engine. Some engines might have a block made from cast iron, cylinder heads made from aluminum, with steel bolts holding them all together. Such a combination of dissimilar metals, and with a fluid flowing between these metals, the conditions are right for the fluid to become very acidic. This would lead to corrosion of everything that the coolant touches. The coolant also protects any of the metal parts that contain iron from rusting.

So the coolant mixture can resist boiling at temperatures up to about 260°, it can resist freezing all the way down to about -40°, and it can avoid becoming overly acidic. This is a lot for the coolant to handle, but with a good mixture of 50% ethylene glycol and 50% water the coolant will be up to the task.

Like every other fluid in a car, the coolant will break down over time. The typical service interval for the regular old green coolant is about every two years or 30,000 miles. Automotive engineers are constantly working on ways to reduce the need for service of the vehicles that they design and build. For the newest cars a newer formulation of ethylene glycol is used in the coolant mixture. This new coolant is referred to as extended life coolant. The service interval for extended life coolant is about 5 years or 100,000 miles.

The problem with all of the different colors is due to every manufacturer coming out with their own version of extended life coolant. General Motors was the first company to make wide use of extended life coolant beginning back in the mid 90’s. The GM extended life coolant is referred to as Dex-cool, and is usually orange. When GM released Dex-cool onto the market they made it clear that only Dex-cool should be used in their vehicles. In subsequent years other manufacturers have come out with their own formulations of extended life coolant and each formulation has been given a different color to make owners and technicians more likely to stick with the factory coolant formulation when servicing their cars.

Extended life coolants work well with one exception, the GM formula Dex-cool. Vehicles that use this formula have a tendency to suffer from major corrosion in the cooling system in as little as 3 or 4 years. The cooling systems on GM vehicles have been known to fill up with a thick, sticky, brownish-orange goo. A nation wide class action lawsuit was filed against General Motors, by owners of GM vehicles because this problem has been so pervasive. Nobody seems to know for sure what is going on with Dex-cool but GM is standing by this product and they continue to use it.
A radiator core from a GM product showing the build-up that is common on newer
low mileage vehicles. This sludge blocks the flow of coolant through the radiator.
 My personal opinion is that Dex-cool is terrible stuff. As an automotive technician I have seen many cooling system failures and engine failures on just about every kind of car out there. I have personally seen GM vehicles with only 40k miles and a cooling system plugged up with this nasty mud-like slime, and Dex-cool that now looks like rusty water. GM says that the problem stems from a radiator cap that doesn’t seal properly, and allows air to get into the system. Whether this is true or not is irrelevant because I have seen many vehicles that have compromised cooling systems in some way that allow air in, and they never suffer the same fate as these Dex-cool filled engines. GM should acknowledge that if their coolant can’t stand up to a bit of exposure to regular plain old air then it is no good. If I had a GM vehicle with Dex-cool in it I would get the cooling system flushed and replace the coolant with regular green coolant or with a good after-market universal coolant.

So what do you do about the various color coolants? The short answer is, don’t worry about it. When you are servicing your cooling system it is perfectly okay to use a good after-market universal type coolant. Companies such as Prestone and Peak, manufacture products that can be mixed with any of the colors without any harmful effects on the engine. The fact of the matter is that even if you mix the old green stuff with the extended-life coolant, your engine will not be harmed in any way. The worst that will happen in such a situation is that the extended-life coolant that is in your system is no longer extend-life anymore and the system will have to be serviced after two years instead of five.

Another alternative to regular ethylene glycol based coolant is propylene glycol coolant. Propylene glycol has many of the same properties as ethylene glycol but it is far less toxic. The reason that this really matters is due to the fact that ethylene glycol has a very sweet taste that attracts the attention of animals. If your vehicle has a coolant leak your cat might notice and drink some of the coolant off of the garage floor. This will obviously kill the animal. Also, considering all of the toxic chemicals that we surround ourselves with, it may be good to eliminate at least one from our daily use. Most manufacturers do not condone the use of propylene glycol based coolants in their vehicles, but the owner of the vehicle has the option to use it if the benefits of its use are important to them.

Stick to the owner’s manual when it comes to servicing all the fluids on your vehicle and you will never go wrong. Service interval is the most important thing when servicing the cooling system, fluid used for the service is less important. Learn how to check your own coolant level so you can perform a routine check. The more you know about maintaining your vehicle, including the cooling system, the better off you and your car will be.