hi,

i was just wondering what you guys look for when buying a used car off of someone say on craigslist. The two big things are the transmission and compression right? would that avoid most big problems? i'd assume you'd test the transmission by driving it and looking at the fluid. performing a compression test on someone elses car is probably not a good idea. can you tell if a car has decent compression just by driving it?

 

You didn't mention what model year range you're looking at, but actually I would be more worried about slow oil consumption as its common and more difficult to detect. Look for a puff of blue smoke out the tailpipe at startup if its been sitting, or have someone follow you with their windows down and floor it to see if they smell oil. If you have bad compression in a cylinder or a bad transmission you'll usually feel it during your test drive.

Bad wheel bearings are also common and should be an obvious one when you drive Also want to check out the frame to make sure nothing has been spliced indicating it was once wrecked. Cupping on the surface of the tires would indicate bad alignment.

Another subtle thing to check is if you hear any weird whirring when you rev the engine, which would indicate an overtensioned timing belt. I've seen it a few times now. Also look for coolant/staining at the base of the timing belt cover which would indicate a leaking water pump.

Look at the coolant resevoir and make sure its within the correct level and look for any signs of milky coloring which would indicate a headgasket leak. If the engine is cold, I would remove the radiator cap altogether to make sure it hasn't lost coolant. With the cap off I would start up the engine and look for little bubbles which would indicate a headgasket leak.

Also look for signs of oil leakage on the bottom of the engine where the transmission meets the block which would indicate a bad main seal.

 

Any smoke coming the tail pipe or engine bay area is not good. Open oil filler cap and try to feel and see if no smoke or excessive air is coming out. Feel the exhaust temperature at the tailpipe, the colder it is the better. High exhaust temperatures would indicate something not good in the engine. Try also to smell if exhaust smells of unburned gasoline. Less noise and vibration is better. Excessive noise and vibration must be checked for extent of work needed to fix the issue. Listen to the radiator fan turn on automatically and take note of how long it is staying on. Longer periods of rad fan run would indicate an inefficient or problematic cooling system.

Drive it hard to the max and note noise vibrations,temperatures and feel of the car. Hit the brakes hard and see if it stays straight. Do fast sharp corners while accelerating and listen for wheel squeels and axle clunking sounds.

 

thanks for the advice. around here the "AS IS" laws are like legal robbery. I'm becoming more and more convinced that the only reason someone would sell a car is if something is wrong with it.

always ask to cold start right?

 

All my car is purchased used.

Used = $ saved, just be smart on the purchase

 

Something I just remembered. Milage also is important. Although there are low milage cars thats crap in and out and there are high milage cars that were well maintained and runs like new, you have higher chances of finding a good car with lower miles in them.

Try to see or ask the seller what were the parts that have been replaced recently. Few or no parts replaced means all those parts will die on you one by one in the very near future.

 

Along the same lines (though its been a while..), I am about to buy a used 98 coupe EX with the stock vtec. Its got auto trans. which I am am too excited about but I might get a good deal. Its 140k now with regular tune-ups, water pump and timing belt replaced at 120k. Anyone has ideas about particular things to check (for this year -- 6th gen) or ask for. Is taking a mechanic along really necessary?