Noises
When you start the engine listen to the noises, they will tell you a lot about its condition. If there is something wrong internally, you hear noises that should not be there. These noises give the professional enough information to deduce the probable cause. In this paragraph we discus two of these noises.
Squeaking noise: a high pitched noise coming out of the engine bay. This noise is coming from the drive belts and the tensioners. These belts drive parts like the alternator and the power steering pump. When a car has not been driven for some time these parts get a bit dry. This causes friction or slipping, which generates an irritating noise. When the drive belts are tightened or greased a little, the noises should disappear. If not, one of the tensioners could be crooked, which prevents the belt from running smoothly. All in all, no reason to panic.
Rattling sound: a rattling sound coming out of the engine bay is a bad sign. This can mean that there simply is not enough oil in your engine or worse: internal wear. Therefore, you should start by measuring the oil level in your engine, before dismissing the car completely. If there is sufficient oil, you have to track down the source of the rattling. You know it comes out of the engine, but from which part? Start the engine and let it run idle. Now rev the engine a little. Do you hear the rattle accelerate at the moment the engine is revving up? If so, it is very much possible that the crankshaft bearing is worn out. If this is the case, you need to overhaul the crankshaft or replace it. The costs for the crankshaft and the labour can go well over a thousand pounds. This shows you what to expect when you buy car without making a test drive or having the proper guarantees.