When choosing a car, you should not neglect the services of specialists, who will professionally check the car and diagnose these or those assemblies and components. However, before dragging the car to the station, it is not superfluous to check the car by yourself. For example, it is possible to diagnose a run-down engine with your own hands, even without special education, skills or serious experience. Probably, the car will be so bad that it will be possible not to ask for help from specialists…
Listen carefully
Any knocking, rattle, grinding and cracking from the engine side is a cause for concern. If some strange knocks are heard immediately after startup, it is likely that the car has problems with hydro-compensators operation. In addition, strong knocks may indicate wear and tear on the pistons. Rattling and rattling after startup is most likely a problem with the timing belt drive. If you hear some strange noises when you try to increase revs, the engine most likely has problems with crank pins. Do you hear a hiss? Then there is a high probability of intake manifold problems.
A look inside
Stop the engine and look into the cylinder head cavity through the valve cover aperture. Ideally, the color of the surfaces should be light. The darker it is, the worse it is. And in no case should black clots be seen – this is a very bad sign. For older engines, the inspected surface may be brown, but there should be no thick deposits on it. When inspecting the cylinder block it is a good idea to use a flashlight. Be sure to pay attention to the oil filler plug: it must be free of liquid drops and heavy black deposits. When checking in winter, there may be moisture condensation or white-yellow emulsion.
Pulling the dipstick
When checking engine condition, be sure to pull and turn the dipstick. The lubricant level should tend toward the top mark. Also pay attention to the color of the lubricant on the dipstick. Under no circumstances should it be too black. Too “clean” oil must also arouse suspicion. In this case there is a possibility that the seller wants to present the car in a better light (than it really is) and changed the oil just before the inspection. If there are soot particles or black deposits on the dipstick, this is a very bad sign. Also, under no circumstances should large amounts of crankcase gases come out of the dipstick hole after the engine is started.
Visual Inspection
It is useful to look inside the engine at least through the valve hole, but you should not forget (neglect) the visual inspection of the power plant. First of all there must not be a big amount of oil and antifreeze leaks on the engine. It is also not superfluous to pay attention to the situation with leaks on the cooling system. On a cold engine be sure to check the expansion tank, in no case there must be no engine oil in it! Presence of the latter is already a sufficient reason to refuse purchasing.
What does it smell?
No, you should not smell anything specially. Especially, if the question is about car exhaust. However, it is necessary to look at the color of exhaust pipe. Too black or vice versa white smoke from the pipe is a sign of serious problems in the engine. A bluish smoke indicates the presence of an oil burner.