Under the Hood

from The Car Book 1998 by Jack Gillis

While many of us find the engine compartment to be a rather intimidating place, these simple checks can help you steer clear of lemons. Items 1 through 8 should be done before starting the car. Items 9 and 10, checking the oil and automatic transmission fluid, should be done after starting the engine.

Before You Start the Car:

1. Check the radiator. While the engine is cool, open the radiator cap to see if there is a shiny oil film on the top of the water in the radiator. If so, engine oil is probably leaking into your cooling system through a cracked head, cylinder block or a leaky head gasket. All are expensive repairs. If the coolant mixture is rusty, you may need to replace the radiator. Stick your finger inside the filler neck and check for sludge. This usually means that somebody added a "stop leak" product to plug up holes in a leaky radiator.
   Caution: Always make sure the radiator is cool before making these checks.
2. Examine the engine compartment. Check the overall cleanliness of the engine, but beware of perfectly clean engines. That's a possible indication that the engine has just been steam cleaned in order to prevent you from seeing various leaks. In either event, inspect the engine carefully and look for leaking around the various components.
3. Look for maintenance stickers. Look around the engine compartment, air filter, underside of the hood, or doorframes for any maintenance stickers put on by a service station. This may provide a clue to how frequently the car has been serviced. A key factor is frequent oil changes. If the owner regularly changed the oil, then your chances of getting a well-running car increases dramatically.
4. Examine the belts. Check the fan belts for cracks or shredding and make sure that they are not too loose. When you push down on them, they should give only about half an inch. It's okay for the belts on a four- to five-year-old car to look as though they need to be replaced -- they probably do. While you check the belts, wiggle the fan blade and other pulleys connected to the belts. If any are loose, the bearings may be gone and they will have to be replaced.
5. Check the wiring. Check any wires for frayed or worn spots and cracks. If the car is more than two years old and all of the wiring looks new, the owner could have had a major problem. This isn't necessarily bad, but it's something that you should inquire about. The wires going to the spark plugs (known as the ignition wires) should have no cracks, burn marks, or wear. If so, they most likely will have to be replaced. This isn't a major repair. It's more an indication that the car has received poor preventive maintenance.
6. Check all the fluids. Inspect the brake fluid, power steering fluid, and windshield washer fluid. Low power steering or brake fluid could indicate a leak in either of those systems, which should be checked out by a mechanic. If the windshield washer fluid is low, put some water in and test the system to see if it works. In general, low fluids may indicate that the car has been neglected overall.
7. Look at the battery. A brand new battery on a car that's less than two or three years old could mean electrical problems. If the car is four or five years old and you're convinced that it has the original battery (it bears a date), you can assume that the electrical system works fine.
8. Check the air filter. If it looks particularly dirty, then the owner probably did not do much preventive maintenance, because changing the air filter is one of the easiest things that can be done to keep a car in good shape.

After You Start the Car:

9. Check the oil. After the engine has been running, find the dipstick to check the oil level. If it's low, then the car is either an oil burner, has some kind of oil leak, or the owner has not replaced what was naturally lost. If the oil is fresh, it will be a clear, amber color; if it is dark, it usually indicates that the oil has been in the engine for some time. The color of the oil is not very significant; in older engines it will rapidly turn dark. Gritty or gummy oil is a sign of infrequent oil change, which could signal that the engine has not been very well maintained. If the oil is milky brown or grey or has small bubbles in it, then water is present and the car could have a cracked block. Very thin oil that smells like gasoline also indicates severe engine problems. Very thick oil could indicate that the owner is trying to quiet the noise from a failing valve lifter.
10. Check the automatic transmission fluid. The automatic transmission has a dipstick, which is usually located at the rear of the engine. Put the emergency brake on, and with the transmission in park, start the car and check the color of the oil on the transmission dipstick. It should be reddish. If it's dark brown and sludgy, the transmission has been poorly maintained. If it has a burned smell, it means that the transmission has excessive wear and could quite possibly fail shortly. If you notice any metal flecks, actual parts of the gears are being ground up. If the fluid level is low, then the transmission leaks.
    (Note: This is a very important check. If you can't find the dipstick, put it on your mechanic's checklist.)