Now that we’ve reviewed the basic principles of engine operation, I’d like to discuss a few of the most common engine problems, how you can identify these problems, and what basic maintenance you should do in order to prevent serious issues from occurring. Even if you don’t have the technical know-how to diagnose or repair your car yourself, having a general idea of what might be going wrong and why will definitely keep you from panicking when faced with an engine issue. Learning to identify common warning signs will also help you to ensure that little problems don’t escalate into bigger ones.
What if your engine won’t start?
First of all, ask yourself: do I hear the engine cranking? If you do hear a cranking sound (i.e. the starting motor driving the crankshaft) but the engine still doesn’t start, then a variety of things could be going wrong.
First, there could be a lack of compression. Remember that if the pistons can’t compress the air in the cylinder, the fuel-air mix won’t ignite. Lack of compression could be caused a faulty seal, either in the valves or the piston ring, or by a hole in the cylinder.
Alternatively, the valve timing could be off, so that the air fuel mix isn’t coming in or the exhaust isn’t going out. There could be a fault in the ignition system, meaning that either the spark plugs aren’t sparking or the timing of the sparks is off. If you’ve run low on oil, then it could mean that the piston isn’t able to move freely in the cylinder. Obviously, lack of fuel could be a cause; this doesn’t necessarily mean that your tank is empty. It could be that your fuel pump isn’t working properly, or the fuel filter is clogged. There could also be a bad fuel mix, meaning that there is either too much air or too much fuel entering the cylinder. This could be caused by the fuel pump or the fuel filter or by water in the gas tank.
If you don’t hear your engine cranking at all or if it is cranking very slowly, then you most likely have a dead battery (lucky for you—this is very easy to fix!). You can jumpstart your car (see previous entry) to get on the road again; if your battery goes dead again, however, it’s probably time for a new one.
What if your engine makes funny noises?
Engine noises can be one of the first clues you’ll have that something isn’t going right. If you notice your engine making an unusual noise, take careful note of the type of noise and when it occurs. For example, does it always happen when you’ve just started the car, or after you’ve been driving a long time? When braking, or when going up hills? Is it a grinding, whining, or clicking sound?
Then, take your car to a trusted service station to have the noise checked out. Since sounds are an important diagnostic tool for technicians, the more detail you can give in your description, the better the chances are that your service station will be able to identify the issue quickly.
Once common—and disturbing—engine noise is backfiring. This is the sound of a minor explosion coming out of your tail pipe. Backfiring occurs when something goes wrong in the combustion process. Possible causes include: a clogged air intake, poorly fitted spark plug wires, incorrect fuel-to-air ratio, and an impurity in the fuel.
If you notice a knocking sound coming from your engine, don’t delay taking your car to be serviced, as this could indicate one of a number of serious issues.
What if your engine overheats and/or you notice smoke rising from the engine?
The most obvious cause of overheating is a lack of coolant in the cooling system. Once you’ve stopped your car, check the level of coolant in the reservoir (I’ll explain how to do this in part two.)
There are a few other common causes of overheating. First, there could be a build-up of deposits in the water jacket around the cylinders; these deposits impede the transfer of heat from cylinder to water. A broken cooling fan or broken water pump would also keep the cooling system from working properly, as would a twisted or broken radiator hose.
What if your exhaust smoke is a funny color?
Ideally, you shouldn’t really be able to see your exhaust smoke, aside from a few puffs on cold mornings. A bit of pale grey smoke is probably also okay. However, if you notice large amounts of dark or thick smoke, it’s a sign that your engine probably isn’t running properly. Do take the time to check the color and density of exhaust smoke occasionally.
Black smoke: This looks dramatic but is likely the result of fairly minor issues. Black smoke is caused when excess fuel is burned in the cylinders, meaning that there is too much fuel in the fuel and air mix. This could be caused by a dirty or clogged air filter. A faulty fuel pump, a carburetor (device that mixes fuel and air, primarily in older cars) that isn’t properly adjusted, or a faulty engine computer could also be the underlying cause.
White Smoke: This white smoke is actually steam that is produced when either water or antifreeze gets into the cylinder and burns along with the fuel and air mixture. This probably means that one of the gaskets, which separate the cooling system from the cylinder, is cracked or leaking. Check your oil as well to see if antifreeze has leaked into the oil (the oil will be cloudy.) See part two for more information on how to check your oil.
Blue smoke: This indicates that your engine is burning oil. Broken or stuck piston rings—i.e. the seals between the piston and cylinder—are the most common culprit. Check your oil levels carefully to see if you notice a leak. If too much oil gets into the cylinder, it will wreck the spark plugs, so it’s best to check this sooner rather than later.
As we’ve discussed, the engine is a fairly complex machine, and lots of different problems can occur. I’ve outlined a few of the most common and easy to diagnose here. In part two, I’ll cover a few of the basic maintenance tasks you can carry out to help ensure that your engine doesn’t develop any of the problems in the first place.
How to maintain your car:
1. Check your oil (once a week)
a. Car at level spot
b. Wait awhile for engine to cool and oil to collect in oil pan.
c. Pull the engine oil dipstick out. (Usually labeled OR indicated in owner’s manual.)
d. Wipe it off, and then insert it again.
e. Oil should be at- or close to- the “full mark.”
f. Oil should be transparent—not cloudy—and a light golden colour. If your oil is a milky white or black color, have your car serviced immediately.
2. Check automatic transmission fluid. Cold engine- “cold” mark (lower one); hot engine— “hot” mark (upper one)
3. Check coolant level (should be between low and full marks.) Add coolant after car has cooled down. (Don’t take the radiator cap off to do so! May be under pressure.) Also check manual; normally a translucent white reservoir to one side of the engine.
4. Check the rubber drive belts at the front of your engine; make sure they aren’t too worn or frayed
5. Have your car serviced: oil and filter change every 5000 miles, full service once a year. More on this in a later entry.
To learn more about this topic, or a broad range of subjects from “How To Change A Tire” to “How To Jumpstart Your Car”, visit DefensiveDriving.com’s Safe Driver Resources website!
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