Make sure the inside parts have no chips or dents, which may indicate a wreck.
If some parts are obviously dirtier or cleaner than the others, they must have been replaced.
If the engine has been replaced and the owner didn’t inform you about it, that’s a warning sign.
Removing the radiator cap check the engine coolant. It should be green or red, but not rusty!
Check the level of the transmission oil. It should be red (not brown) and should
not have burnt smell.
Inspect the inside of the engine where you add oil. It should be clean.
Check the color of the oil. It shouldn’t be coffee, creamy or white colored.
Don’t even continue inspection in this case.
Black is acceptable, but this is an evidence that the car has been driven hard or the oil hasn’t been changed for a long time.
Check the oil level. Does the owner keep it correct?
Check the brake fluid container. You can find it behind the engine compartment on the driver’s side.
Low level indicated brake wear or leakage. Focus your mechanic’s attention on this.
Stand behind the car, ask the owner to start the cold engine and
see if smoke goes from the exhaust pipe at startup. Blue smoke (oil) usually means that the
engine is worn down and will need to be replaced soon.
Much white smoke means coolant leakage.
Check the tail pipe. If it’s black inside and it’s not diesel, that means
high gas consumption because the gas isn’t burned normally. For diesels, black is normal.
Start the engine yourself. Does it turn and off on easily?
Listen for ticks, clicks, growling sounds in the engine.
The motor must be running smoothly, no shaking or tucking.
Check the blowby. All worn cars have blowby, it’s normal.
But if large amount of colored smoke is coming out and puffing sounds are produced,
that means that one of the cylinders has bad compression or the engine is worn down.
Ask when the timing belt has been changed (if applicable)
Ask when the battery was changed (if at all). A five-year-old one is junk.
Switch on air conditioner. Open the hood and look at the compressor (on the passenger side).
If you can hear frequent clicking sound it may be low on freon.