Re: Buying Audi 100/5000 - what to check/avoid?

[Wallace White <wallace@remdesign.com>]

Here's the checklist I used, based entirely on suggestions from the
list. Some of these won't apply to the 100 (non-turbo), but most of the
stuff is the same. This doesn't cover everything, of course, but it
should help. 

It seems that there have been a few requests for this of late, so I'll
just go ahead and send it to the whole list again:

'86-88 5kcstq Checklist
-----------------------

Under Hood:
- check steering rack and pump leaks; look for broken bellows on rack
- check hydraulic fluid reservoir, look for Pentosin (green fluid) leaks
anywhere
- check radiator for plastic breakage
- check turbo coolant pump for leaks
- check turbo hoses for cracks
- check timing belt condition (can't really tell, though)
while running:
- listen for lifter noise at startup, not unusual
- listen for P/S pump noise
- listen for fuel pump at rear (some noise acceptable)
- listen for exhaust gasket / manifold leaks at throttle
(tick-uh-tick-uh sound)

Under Car:
- check inner and outer CV boots for small tears
  - look for splattered grease where it may have shot out
- check bushings (probably cracked, not a real big deal)

Interior:
- check all switches for windows and sunroof and high beams
- check power locks
- listen for noises from frayed cables in window regulators
- check seat heaters (if you care)
- check A/C flow through center vents (vacuum-controlled flaps)
  - if failed, defrost will blow through on AUTO
- check trip computer

Driving:
- check for 1.2-1.3 bar max boost 
  - check WOT switch and fault codes if necessary (after running)
- listen for no turbo whine
- listen for CV joints and wheel bearings while turning
- check differential lock engagement when stopped
  - 'ABS OFF' light should activate for 1 or 2

After Driving:
- check brake bomb ($280 + easy 1 hr labor)
  - run engine several minutes, then shut off
  - >20 pumps to stiff pedal good, 10-15 weak, < needs to be replaced
  - after shutoff, brake light will come on after ~1 min. if bad
- listen for radiator fan and turbo cooling pump after-run

Service History:
- timing belt and water pump (90k)?
- clutch master/slave cylinder ? clutch?
- steering rack and/or pump?
- brake bomb (hydraulic pressure accumulator) (~5 yrs)?
- CV joints?
- wheel bearings?
- radiator?
- ISV (idle stabilization valve)?
- starter?