Sunday, April 24, 2011

Pre-Owned, Used, and Just Plain Junk

Find A New Ride With Less Worry
Everyone is afraid of something. Some people would rather die than give a public speech. Some people are afraid of the dark, or pain, or spiders. And some people are deathly afraid of buying a used car. Some people are so afraid of buying a used car they over extend themselves financially in order to purchase a new one. They tell themselves this is justified because with a new car they have a warranty in case something goes wrong. If they were to buy a used car they likely would not have a warranty to fall back on if repairs are needed. Nevermind the fact that paying for car repairs on a used car is almost always cheaper than making payments on a new car.
Buying a used car does not need to be a frightening proposition and most people can pick out a decent car on their own if they will follow a few simple rules. People become forgetful when they go to buy a car. Part of the reason is buying a car can sometimes be very exciting, fun, or scary (as I said before). If the experience fits into one of these categories then that means emotions will be involved. Our emotions get us into trouble, whether it’s a fit of road rage resulting from being cut off in traffic, or the excitement of test driving an expensive sports car that is not only too expensive, but doesn’t really fit our needs. Emotions don’t often help us make sound decisions.
The first rule when buying a used car: Do your homework. Find out what kind of options you have in selecting a car. Don’t select a car based on looks, or family tradition (my daddy drives a Ford, his daddy drives a Ford, so I have to drive a Ford). Take the time to find out which cars have what options. Should you get a sedan with a four cylinder engine or a sedan with a V6? What in the world is a V6? Figure these things out before you go looking. With the amount of information we have available to us online it is just plain silly to begin searching without checking out some great websites that have great information for used car buyers. Check out
If you are going to buy the car with cash, then congratulations on being so abnormal. If you are a normal person and you will be financing the car, get your finances in order and get you approval upfront. This will help you to determine how much you can spend. Remember that the amount that the bank approves should never be the amount that you spend. You should always spend less. In the long run you will be much happier when trying to make the payments. Usually it's best to get a bank loan rather then arranging the financing through the dealership but this is not always true.  The thing is, if you arrange through a bank or something like that you have more latitude in your shopping. Once again, do your homework, it's not all about monthly payment. Interest rates mean things.
Find out how much your new car will cost to insure, and find out how much the new car will cost to service. Both of these amounts together should figure into the amount that you arrive at when determining what kind of monthly payment you can afford. Not only can you look at routine maintenance costs but there is information out there that will give you an idea of how much the particular car you are after will break down in a given year, and how much it typically costs to make these unscheduled repairs. Even the cost for a year’s worth of fuel can be determined.
The second rule when buying a used car: Do NOT shop model year. Many people will look at their situation, set a dollar limit on how much they can spend, and then set off to get the newest thing that they can buy for $10,000. How new a used car is has nothing to do with whether or not it will be a good car. This may come as a shock to some of you unless you have owned one of these cars, but some cars were junk even when they were brand new. This is not as much of a problem as it used to be because all cars are so much more reliable than they used to be, but machines still break, and sometimes it’s for no reason. Do some research and find out which makes and models have had the most problems during the time that they have been on the market. This is information that you can never get on a brand new car because they are brand new, and nobody has seen any problems yet.
What the car is has more to do with whether or not it’s a good car, than how new it is and this is something that is quite often reflected in the resale value. Honda and Toyota have really high resale values and very low depreciation. This is because they are perceived by the general public as being  reliable cars. Something like a Suzuki usually has a very high depreciation and can be purchased cheaply when it’s only a few years old. For example, if you are comparing a 2005 Ford Fusion to a 2005 Chevrolet Malibu, the Ford may always be more expensive if all other considerations are equal (this may not really be true this is just an example). Some might argue that just because the Ford will go for more money doesn’t mean that it’s a better car. You can make this case if you wish but do some research on known problems with any two similar makes and models and you will find that when comparing apples to apples, the car with the higher resale value is usually more reliable. This means that you have to compare midsize sedan to midsize sedan, and luxury SUV to luxury SUV, and so on. Don’t compare a four door Ford to a four door Mercedes. The luxury car will usually have a higher resale value no matter what.
The trap here lies in the fact that people will shop model year and they will say to themselves, if 10,000 dollars will buy 2005 Ford Fusion or a 2008 Chevy Malibu then the Malibu is the better choice, or the choice that gets you more for your money. Getting a newer car is not getting more for your money; it’s giving you a false sense of security. When buying a used car you want qualitative advantage, model year doesn’t necessarily give you this.
The third rule when buying a used car: Mileage doesn’t mean as much as you think it means. Sometimes a very good car at a very reasonable price might be skipped over because the mileage is too high. Much of this relates to the second rule. A car that is reliable will usually maintain its reliability even into very high mileage ranges. A car that is very old is likely to have high mileage, but if it’s a car that is good to begin with, the risk of major failure at any mileage is lower, this includes failure at high mileage. A good car that is well taken care of can be a reliable car all the way up to 300k miles. Buying a car with over 200k miles might seem crazy but if you only have 3 or 4 thousand to spend, you might need to check out some of these reliable high mileage vehicles.  Note: I have never had a vehicle myself that had less than 150k miles on the odometer. I have had more than a few with well over 200k miles. These cars were all perfectly reliable and I would drive them any distance with confidence. I was very picky when purchasing these cars and bought exactly what I was looking for.
The fourth rule when buying a used car: Open your eyes. Anyone can spot a fluid leak. Anyone can see what a bald tire looks like. Anyone can see when interior upholstery is trashed. If you are the kind of person that knows nothing about cars except for how to put gas in them, and how to drive them, you must still take the time to go over the car with a thorough visual inspection. Get down on your hands and knees and look under the car. Look under the car at the front, the back, the side, look at the tires, look under the hood, look at the oil, look under the radiator cap, look at everything.
Under the engine and under the hood you should not see any fluid messes. Some people think that any engine will have some oily spots or greasy spots because that’s what engines are full of, but this is not true. If there is greasy fluid residue on the outside of the engine then it is the result of a leak. The untrained individual may not be able to tell where it is coming from but they can certainly spot it when it’s there. If any of the warning lights in the instrument cluster are on while the vehicle is driving, this is a problem. Sometimes the person who is selling the car will even tell you that the light is no big deal and doesn’t mean anything. If one of these lights stays on then something on the car is broken.
If the interior of the vehicle is a pig sty, what does that say about the interior of the engine? If a car owner doesn’t take care of the interior of the vehicle then its safe to assume that they might not take care of the vehicle maintenance needs. Scratches, dents, and dings can happen by accident, but old drink cups from two weeks ago still sitting in the cup holder, and French fries in the glove box are not an accident.
Typical underhood label that will be missing if
the car has been in wreck that smashed the hood.

Being able to tell if a car has been in a wreck or in a flood is usually fairly easy as well. To tell if a car has been in a wreck there are certain labels that you can look for. Every body panel on a car has a label with the vehicle identification number on it. Lift up the hood and look at the top of each front fender for this label. If it’s not there then you know that this body panel has been replaced. Look for the emissions labels that are almost always found on the underside of the hood. When a car is in a wreck that is serious enough that the hood requires replacement, the body shops never replace these labels. If the fenders and the hood are not original then this tells you that the wreck may have been serious enough that other problems might be hiding elsewhere. Remember however, that just because a car was in a wreck does not mean that it can’t be a good car; it just means that if it wasn’t restored properly then you might have problems in the future.

To tell if a car has been in a flood look at metal pieces on the interior of the vehicle that should have never been exposed to moisture. Things such as seat tracks under the driver’s seat are good. Check for any hint of rust or corrosion on these parts. If you see any there could be a problem. If you a feeling really adventurous you could look at one of the many electrical connectors under the hood. Disconnect it and have a look at the pins. They should be totally dry and free of corrosion. A car that has been in a flood could still be a good car if it’s repaired properly but there is more risk with this kind of a car because it is hard to tell is all of the corrosion has been taken care of. A tiny bit of corrosion in one connector somewhere on the vehicle can cause all kinds of electrical gremlins to come about, and these problems might not manifest themselves for years after the initial incident.

So is it better to go to a dealership or to buy the car from a private individual? This really is not that important. The important thing is the vehicle itself. Many people have been taken advantage of by both private sellers and used car dealers. Private individuals are more likely to rip you off by selling you something that has had the odometer tampered with or the emissions control equipment messed up, but the used car lot is more likely to sell you something that has been cleaned up on the surface but underneath its got problems. Used car lots are also more likely to sell you something for way too much money.

The advantage of the car dealer is that they are a bit more accountable for what they are doing. They run a business and therefore they must have a license which includes a special dealer’s license in most states. They can give you a temporary license for your car the minute you purchase it and they will get your permanent plates for you so you don’t have to hassle with the DMV. They may have a large inventory, and access to more cars if the one that you want isn’t found in their current inventory. In most states dealerships are not allowed to sell a car on the lot that will not pass local emissions and safety inspections. Many of them may sell a warranty of some kind with the vehicle which may come in handy some day. Used car dealers that are part of a new car dealer also may sell certified used cars, or as they like to call them, pre-owned. These are cars that are sold with extended warranties issued by the vehicle manufacturer. These are the best kind of warranties. In order to certify the used car the dealership service department must go through a check list and inspect and replace anything that needs service or might need service soon. For example, if the battery is still good but is over a certain age than it must automatically be replaced before the car is sold.
The biggest advantage of buying a car from a private seller is that they are not selling the car in an effort to make money; they are usually selling the car in order to just get rid of it. This means that many times you can find the best deals by purchasing a car this way. Many of the other conveniences are lost however, and in some situations these conveniences might be worth paying a little extra.
If all of this is still confusing and you still don’t have confidence about going out and finding some new wheels for yourself then there is one more thing that you can do, and perhaps you should do this regardless of your level of confidence. Take the car to a third party expert and have them check it out from top to bottom. Most shops will do this for less than $100. This is a small price to pay if it means that you can buy with confidence. If they find a problem with the car then you can be glad that you didn’t spend the money on something that was on verge of failure, or you can use the new information as ammunition in the negotiation of a lower sale price for the vehicle. Either way you win.

All of the above rules and tips could be followed perfectly and it’s possible that the buyer might still end up with a piece of junk, but that’s life. Nothing every works out perfectly. However, when a person is confident going into a situation it makes the situation mush less uncomfortable and not so scary. Be confident with the purchase of your next car, and not scared. You can find a good car, and ignore all of the junk.

Tuesday, April 19, 2011

Performance Tuning

If you don’t like the way your car runs then tune it

Most people have heard of tuning a car but most probably don’t know what that even means anymore. Most people, who think they know, probably don’t because the whole concept has changed so dramatically even in recent years. Tuning a car can be compared to tuning a musical instrument. If the goal is to make sweet music on all the right scales then the thing must be tuned according to the rules. Fundamentally, tuning a car means the same thing that it always did, but the means whereby a car is tuned today is completely different from what it used to be.

Tuning a car is not really the same as performing what is commonly referred to as a tune-up. When you take your car to the shop for a tune-up they are usually going to perform a bit of routine maintenance to systems that generally relate to engine function. Things like spark plugs, distributor caps, and other such things get replaced as part of a tune-up. This is fundamental to engine tuning but it’s not tuning.
Tuning involves making changes to the way the various engine performance systems perform their various tasks at the most basic level. In the old days this meant changing things such as carburetors and distributors with different parts to help you get a desired result. If parts were changed then usually they also had to be adjusted. Tuning does not always involve replacing parts; it might just involve adjustments to engine performance systems.

There are many different reasons to tune a car but the one that is most common, and the one that is the most fun is tuning the car to increase performance. Just about every driver out there wishes that they had a little more power. The other thing that some people go for when tuning is higher fuel economy but this is a distant second. Usually tuning is not done to the daily driver or the commuter, this is something that is usually done to the project car, the Sunday driver, or the midlife crisis type car. These are the cars that people like to upgrade in some way so they can be driven fast and their owners can have fun doing it.

Since today’s vehicles are so advanced, there are really no adjustments that can or need to be made anymore. Parts can still be upgraded but once they are bolted on there is not much more that can be done because as far as adjustments are concerned they are all taken care of by the computer that is in charge of controlling the engine and all of its functions. In order to tune the vehicle in any way the computer must be changed in some way.

In the early days of computer controls this involved the changing of the programming within the computer by either replacing the entire computer, or just replacing or reprogramming the read only memory chip inside of the computer. While it’s easy to replace the computer it’s expensive to change hardware that isn’t really bad, just to get a new set of instructions to the engine. Replacing the PROM chip in the computer is easy as well, but if the programming wasn’t exactly right then it meant getting another chip, or taking the chip somewhere to get it programmed. The term “chipping” the car came from the practice of swapping out the PROM chip in the powertrain control module.

A replaceable program chip installed in an old engine control module

Over the past ten years this tuning process or reprogramming process has gotten much simpler. All vehicles built today, now have an engine control computer that can be easily reprogrammed with the proper software installed on a laptop computer. Some companies even make special scan tools that can be cheaply purchased specifically for tuning and reprogramming engine control computers.

This has all come about as a result of a federal mandate from the EPA. Independent auto shops need to have the tools and ability to reprogram engine control computers. According to the feds this is primarily for the purpose of updating software to help cars stay clean and efficient, and reduce air pollution caused by excessive emissions. The EPA mandate is that reprogramming capabilities be standardized in such a way that the aftermarket shops and tool manufacturers can program computers on any car. This means that independent software engineers can more easily crack the code used by each auto company in their engine control computers.

Of course tuning for performance has nothing to do with this EPA mandate, it’s just something that has gotten easier as a result of the action by our government. People out there who are tuning their cars without knowing what they are doing are likely creating situations where their car is polluting much more than it should, but more pollution is not necessarily the result of tuning. Many times when a vehicle with performance modifications is tuned for optimum performance, the tuning will also result in making the car more efficient in every other way. More power quite often goes hand in hand with low emissions levels. This means that an engine can be modified to produce more power, and still have emissions levels at the tailpipe that are very similar to what was there before the changes were made, and the vehicle can still easily comply with county, state, and federal emissions standards.

Tables that make up the basic operating instructions deep within
 the engine control module can be changed
The things that get changed in order to tune the car are things like fuel delivery tables and spark timing schedules, throttle control and other things. This does not mean that more fuel is added to make the car faster; it means that the proper amount of fuel will be added to go with the amount of air that is entering the engine. This air fuel ratio must be within specification in order to make the engine run efficiently. These ratios are essentially the same for high performance engines as they are for stock engines. Automatic transmission shift patterns can also be changed to help optimize the performance of the engine.

As mentioned previously tuning a vehicle with today’s advanced technology should not be attempted by just anyone. If a vehicle is tuned improperly it can lead to anything from terrible fuel economy or high emissions, to major engine damage. Some companies manufacture a device that can be hooked up the vehicle’s datalink connector, and new programming can be up loaded into the engine control computer. These programs are pre set and cannot be changed or altered in a way that would be detrimental to the vehicle. This is a simple way to tune but it might not do exactly what you want, or exactly what needs to be done. If anything custom needs to be done to properly tune the vehicle then a more complex process will be involved. Many different companies out there can teach you to custom tune a vehicle for performance but one of the very best is The Tuning School.

Based out of Florida, The Tuning School offers easy to learn curriculum that allows the eager student to learn how to properly tune modern vehicles using such programs as HP tuners or SCT, both of which are leading tuner programs that are on the market. The thing that makes The Tuning School great is that they offer DIY courses that can be done at home, and they also offer courses in different places around that country, that take the form of a two day seminar with hands-on training. These seminars happen at places where modern chassis dynamometers are used to run the vehicles being tuned in a controlled and safe environment. Using a chassis dynamometer is the best way to run the vehicle because as mentioned it is safe, legal, and the dyno can measure things such as horsepower and torque to help track tuning changes. Tuning can be even more fun when you have received instruction to help you do it properly. For more information on The Tuning School, check out their website:

Friday, April 8, 2011

Hot Bags of Gas

Cars are getting safer, technology is the reason

Despite the fact that many people die in automobile accidents every year, the modern auto is much safer now than it has ever been. In a study released by the U.S. Department of Transportation, 2010 saw the lowest death toll on U.S. highways since Harry Truman was in office. 2010 saw 1.09 deaths per 100 million vehicle miles traveled. This is the lowest this statistic has been since 1949 when the Department of Transportation first began to compile such data. This stat is especially significant if you consider that every year Americans travel more and more miles in more and more vehicles.

The reasons for this good news are varied. People pay more attention to safety then they used to. Seat belt use is the norm. The parent who fails to buckle their kid into a car seat is viewed as neglectful, and kids are no longer the seat surfers that they once were. People think about things such as distracted driving, drunk driving, and drowsy driving much more than they used to. Perhaps the biggest reason for this decline in traffic deaths is the abundant technology that is now incorporated into the modern automobile for the purpose of making them safe.

Consider the following video. This was produced by the Insurance Institute for Highway Safety. They are the people that do all of the crash testing and safety scoring of each vehicle sold in the U.S. In this video they run a 1959 Chevrolet Bel Air into a 2009 Chevrolet Malibu. The results are startling.

A popular misconception is that the old vehicles were safe because they were heavy, and solid, and made of steel, not plastic. This is not true as this crash test clearly shows. People who used to get in a wreck while riding in an old car used to get decapitated on the steering wheel, and get their bodies smashed to bits slamming into a steel dash.

Modern vehicles have things like crumple zones. These are areas of the body and chassis that are meant to absorb the impact instead of passing it through the vehicle into the passenger compartment. New cars are built so that if a head on collision is serious enough to break the engine loose form its mounts, it will actually dive under the vehicle instead of ending up in the laps of the front seat passengers.

Modern cars have all sorts of electronic safety measures built in. Anti-lock brakes allow the driver to steer under maximum braking. Anti-skid control is now so advanced that it can take control of the accelerator away from the driver, and also take brake control away from the driver in order to counteract steering inputs, and get the vehicle going straight down the road again. Cars are even smart enough to tell if you are wandering in your lane. They can also see a sudden stop of the vehicle in front of you and begin to apply the brakes before you do.

All of these things are passive; they require no action on the part of the driver and will just do their thing whenever necessary. Of all of the passive safety systems, the one that is perhaps the most controversial, but maybe the most effective, is the supplemental restraint system (SRS). This is the system that controls the airbags. The controversy centers on the fact that an airbag going off in your face is a scary thought. Many people have been in a wreck, had an airbag deploy in there face, and came away with a bloody nose, minor burns, or abrasions. This is nothing compared to a fractured skull and massive concussion from hitting the dash. In a few incidents children have been hurt by airbags but in every case the child was in the front seat, not restrained at all, or sitting in rear facing child seat. These are all primarily the fault of the adult driving the car, and in some cases the child probably would have been launched through the windshield anyway.

So what makes the airbag work? The controls and actuators essentially boil down to a computer controlled, pyrotechnic device that burns a propellant and inflates a bag with nitrogen gas if the vehicle is involved in a wreck at 15 mph or faster. This small explosion is hot and powerful but very effective. Some types of airbags will use a pyrotechnic charge to release a canister of highly compressed gas to inflate the airbag. The typical inflation time for an airbag is about 30 milliseconds (1000 milliseconds in one second). In less than half a second the airbag deploys and is already beginning to deflate. White smoke can usually be seen after airbag deployment, this smoke is essentially sodium carbonate which is totally harmless. This powder protects the airbag while it remains packed into the assembly over the years.

The airbag must be triggered by two different sensors in order to deploy. Typically these sensors are mounted in the front corners of the vehicle to deploy the driver and passenger airbag, and in the B pillar to deploy side airbags. The SRS control unit which is usually mounted in the center of the vehicle near the floor also may contain a sensor that can sense the rapid deceleration that occurs with a major impact.
Airbag sensor
Besides the driver and passenger airbag which became mandatory starting in the 1994 model year, vehicles now must also have side airbags that come out of the seats or the doors to protect occupants in the event of a side impact. New cars also have side curtain air bags which pop out of the roof liner to protect the occupants head and shoulders from slamming into the windows, doors, and side pillars. Some vehicles also have knee airbags that come out of the lower part of the dash, center airbags for rear seat passengers, or even shoulder strap airbags that come out of the seat belt itself.

SRS systems on the most modern cars are more intelligent that the airbags that were mandated back in the mid 90’s. Before an airbag will deploy in will look at things such as the position of the seat to determine how the airbag should be deployed. If the driver is sitting very close to the steering wheel like your grandma does, then it will deploy the airbag with less force. If there is a short person sitting the passenger seat it will deploy the airbag with less force, because it can sense how tall the person is. If a small child is sitting in the passenger seat and seat belt is buckled it will deploy the air bag with less force. If there is a child in the passenger seat and the seat belt is not buckled it will automatically turn off the airbag.
Plenty of airbags to go around
This system that is so intelligent is known as the occupant classification system (OCS). The system uses strain gauges built into the seat mounts, or something similar, to weigh the passenger. It also uses sensors on the seat track to see how close the seat is to the dash. The system incorporates special antennae in the seat cushion and seat back to classify the height of the passenger, and determine the position of the passenger in the seat. If the passenger is leaning against the window taking a snooze the system will see this and it will disable the side impact airbag. Indicator lights on the dash will tell the occupants of the vehicle which airbags might be disabled in certain situations. Pickup trucks have an off switch on the dash that allows the passenger airbag to be completely turned off. This allows kids to be buckled safely into the passenger seat and it also allows the use a rear facing child seats.

Devices known as seat belt pretensioners are also controlled by the airbag system. These devices are found in the shoulder strap retractors or in the seat belt buckles. They are there to tighten the seat belts against the occupants to more firmly restrain them in their seats. These pretensioners use a much smaller explosive charge to accomplish this task very quickly.

The SRS system is continuously monitored by the computer that controls everything. When there is a failure or break-down in the system that might cause the airbags to fail to deploy, the control unit will illuminate the airbag or SRS light. This alerts the driver that the system has a fault and ought to be checked out by a qualified technician. The technician will be able to interface with the SRS control unit and find out what the problem might be.

Cars are probably not as safe as they can be but they are much safer than what the used to be. Supplemental restraint systems are a large part of the reason for the increased safety. Despite the controversy, airbags have proven to be safe when they are used correctly. The future of auto safety is hard to predict. The devices of the future are likely just things that we haven’t thought of yet. Considering the downward trend of deaths from traffic accidents cars are likely to only get safer.

Wednesday, April 6, 2011

Needles and Scales

Back in the old days the instrument cluster on the average vehicle was much easier to understand. The main reason for this is that cars were simpler. You might instead say that back in the old days cars weren't very smart. Today cars are both more complicated and much more intelligent. Gauges are no longer displaying a value based on a sending unit attached to the gauge. All gauges are now computer controlled and the computer receives the info that it commands the gauge to display from all sorts of different places. Not very many people really understand what all of the needles and scales refer to when they go sweeping back and forth. Some might have an idea but they don’t really understand all of the implications of each gauge.

Most likely the speedometer and the fuel gauge require no explanation. There was a brief period when a few manufacturers got rid of all gauges except these two because they figured that nobody cared about the others. The thinking was that lights could be used to alert the driver if a major problem was imminent but it wouldn’t show the driver how bad, it would just turn on a light. Perhaps this is true for some drivers but not for all so most cars and trucks again have more than just these two.
170 mph...I don't think so!

If your car dies and will not restart, take a glance at the fuel gauge. If the needle is pointing to the E, go ahead and put some gas in the car before you have it towed to the shop for repairs. More than once a distraught car owner had their car towed into the shop as a no start and it was just out of gas. Even if the gauge is not all the way on the E, it might still be out of gas because none of the gauges in the instrument cluster are totally accurate all of the time. Speedometers are usually only accurate within a few miles per hour, and the faster the vehicle is traveling to more inaccurate the speedometer may become. Some speedometers will show a top speed on the scale of something that is really unrealistic. The highest number on the speedometer has nothing to do with the vehicles top speed.
A special fuel gauge for people who drive a car that's a gas hog.

The tachometer is the gauge that tells you how fast the engine is turning. At idle the gauge will usually read around 600 or 700 revolutions per minute (RPM), and when driving down the road it will read whatever speed the engine is turning. Towards the top of the scale there may be an area that is colored red. The area of the scale where this red coloring starts is referred to as the engine “red line”. The red line is where the engine is turning too fast for its own good and may suffer some kind of damage if it remains at red line for too long. Usually there is never any reason to run an engine so fast because by the time it reaches red line it’s no longer producing any more power, and the vehicle won’t usually continue to accelerate, unless the transmission can shift into a higher gear and the RPMs drop back down into the range where torque can be further multiplied. Generally speaking, when driving the vehicle, the lower you keep the RPMs the better fuel economy you will have, as long as you don’t let them get too low.
A red line of 8500 RPMs is very high. This must come from a performance car.
I think the 138 MPH confirms it.
A coolant temperature gauge is found on almost all vehicles. This gauge tells the driver how hot the engine is. Many times, this gauge will not have any numbers or delineations of any kind, or it may just have a C at one end and an H at the other. Whether it has numbers on it or not, the driver of the vehicle should remember where the needle usually sits because if the needle moves up it means the engine is getting hotter. Running an engine too hot will cause serious damage. Many temperature gauges will have an area near the top of the scale that is red. Never let the needle get into the red, and if you can help it never let the needle get anywhere near the red. Pull over and watch the gauge with the engine idling. If the gauge continues to climb shut the engine off and let it cool down. Just for reference, and incase your gauge does have numbers on it, the engine temperature should be between 190° and 200°. If it gets as hot as 220° that can still be acceptable. If it gets above 230° it would be time to get nervous. If the gauge needle hardly moves off of the lowest point even after the vehicle has been running for some time, there might be a problem with over cooling. This can cause a lack of power and poor fuel economy. Ideally the temp gauge should never move once the engine is warmed up.

The oil pressure gauge is one that is commonly found on trucks and performance cars. This shows the oil pressure on the main oil galleries deep inside the engine. Oil pressure must always remain at a level that will allow the crankshaft to be properly lubricated in its bearings. This gauge usually just has a normal range in which it should operate. The rule of thumb for oil pressure is a minimum of 10 psi for every 1000 RPM. When the engine is cold the pressure will always be at the high end of normal. Once the engine gets hot the pressure will be high when the engine is running at high RPM and low when the engine is running more slowly, but it should always stay in the normal range. If oil pressure drops too low engine damage will occur, especially if the oil pressure drops low while the engine is turning quickly or under a heavy load. If all oil pressure is lost pull over immediately and turn the engine off.

The last gauge that is common is the volt gauge or battery gauge. This gauge displays what the voltage is in the electrical system with the engine off, and with the engine running. The scale will usually just show a “normal” range rather than numbers. Regular electrical system voltage when the engine is running is anywhere between 13.5 to 14.5 volts. The needle should usually stay in the normal range but will usually be lower when at idle and will go up when the engine accelerates. Movements of the needle should not be too drastic however. If the gauge falls considerably when the engine is running this can be a problem and could eventually cause the engine to stall. If electrical system voltage falls too low then there is not enough electricity to run the fuel pump.

Old cars and trucks had an ammeter instead of a voltmeter. Because of the way the ammeter functions it’s easier to hook up a voltmeter on modern cars. Both gauges give an idea as to how the alternator is functioning, and whether or not it is charging the battery and providing power for all of the electrical systems while the engine is running, but the voltmeter will even work when the engine is not running. When the key is first turned on the voltmeter still shows how much voltage is in the electrical system but it only showing voltage from the battery and not from the alternator. A fully charged car battery should have 12.6 volts, but with the battery installed in the vehicle and the key turned on, the battery ought to have somewhere between 11 and 12 volts.
Oil pressure, oil temperature, coolant temperature, and fuel level.
 Some other gauges that you might find on a vehicle would be an engine oil temperature gauge. This is another way of monitoring engine temperature. A transmission temperature gauge is somewhat common. This is to show how hot the transmission is, and is usually found on things like big pickup trucks that may do a lot of towing. Vehicles with a forced induction system such as a turbo charger may be equipped with a boost gauge. This gauge displays how much pressure is building up in the intake manifold. The more boost, the more the turbo is working.

Because everything on the vehicle is computer controlled, including the instrument cluster, and because the vehicle shares so much information back and forth between all of the different computers on the network, some vehicles have customizable displays that can show many different types of gauges. Computers such as the engine control module receive all kinds of information from various sensors and inputs. This control unit also performs many calculations related to vehicle function. The computer that controls instrumentation can easily pull all of this info off of the network to display it for the driver. Even though most gauges have an analog needle that points to numbers or ranges on some kind of scale or dial, they are still digital gauges because the controls are digital.

Numbers and pointers mean things. The things that these gauges display are important. Every driver out there should be able to read and comprehend all of the gauges on the cars that they drive. Not only should the driver be able to read the gauges but they should also watch them constantly as they are driving. A simple part such as a $10 thermostat can destroy an engine by allowing it overheat. If the driver of the vehicle sees the temperature go up and takes action to prevent over heating, then all they have to pay for is a thermostat rather then pay for a new engine.