Buying Used Cars: Quick Ways to Spot a Lemon


by Colette Cooley, Cars for Keeps Office Manager

Lemon or lovely – that is the question when you consider buying a used vehicle. It may look gorgeous on the outside, but the inner workings determine whether or not the car will be a money pit. Here are a few tips on what to look for when test driving that little beauty:

1) Pull out the oil dipstick while the engine is running – be careful not rev the engine! Watch the dipstick’s hole as the engine idles; if you hear or see any air, gas or oil escaping the dipstick holder it means the rings are worn. A slight escape of air from the dipstick is the first stage of ring failure which is not a serious problem but will get worse until gas and oil start escaping the dipstick holder. The result is less power and leaking oil in the sump. Look for white emulsification on the dipstick which would indicate a cracked cylinder head, which is a serious problem.

2) Look at the exhaust pipe while the car is running. White smoke from the exhaust indicates there’s engine oil remaining on the bore that the rings haven’t scraped off, which means oil could be leaking. Black smoke means the fuel injectors are dirty on a diesel engine.

3) Remove the radiator cap and check for oil. Oil in the water also means a cracked cylinder head.

4) Have a pre-purchase inspection performed! A compression test should also be done for failing rings on any used vehicle. This test requires a trained mechanic because of the equipment used and the test is complicated. The readings must be done ‘dry’ and ‘wet’, and it even depends on if you are above or below sea level.

At Cars For Keeps, we do a bumper to bumper inspection on used vehicles before you buy it, and we have saved a lot of people from buying a ‘money pit’.