The basics of buying a new car are:
Don't rush into anything.
Never trust the seller (especially if they're a dealer)
Get a HPi check
If you're really worried, get an AA Inspection
Inspect ALL the paperwork
Make sure the numbers match
Looks for signs of clocking (check the mileages on MOTs/service records etc tally-up, looks for signs of wear, i.e. worn seats/pedals, shiny steering wheels, etc, etc)
See it when the cars cold, not warmed-up
Test drive it (make sure you're covered re. insurance)
Then if your still interested then look at:
One main thing to check for is if you take off the oil filler cap and you can see a cremy off white substance this will tell you the head gasket is leaking/knackered! (applys with most cars)
But then again it could also be a build-up of condensation from short runs, which is nothing. If you do find the signs of a blown head gasket, it might be better to walk away as if it is gone it will be expensive to fix.
Check for rust around the sills and the crossmembers as they are expensive to fix. Also check under the car for any damage or holes in the exhaust.
Other simple things to look at are:
- does the clutch slip
- is the oil clean
- do the brake pads have life in them
- do the discs have a lip on them
- are the discs warped or have grooves in them
- is the tread wear even on the tyres
The last thing to check is to see if the car is straight. Look for creases in the chasis as it might have been in a accident. To check the body panels, stand level with the car but at least 2-3 feet away from the front and the rear and look for ripples, lumps/dips as they show the car has been hit and there is filler on the car.
To check clutch slip there are two ways that i know
1) on the test drive go up a steep(ish) hill if you need more revs than actually needed to get the car up the hill then its starting to slip.
2) When stationary with the hand brake on put the car into fourth gear, start to slowly take your foot off the clutch if the car starts cutting out when the clutch plates start to meet then the clutch is fine. If the car doesn't cut out then you know the clutch has gone.
If this is the case i would say walk away as the car might have been treated badly. Usually if a clutch is slipping (on low powered cars anyway) the brakes are in a state as well.
Mike