Also, make shure the car has no rumbling noises from the rear diff when driven on full lock and there are no rattles/clunks from the suspension. The front and rear suspension are rather complicated multi link independent suspension and prone to failure- only use quality parts (lemforder/OEM or meyle heavy duty) as cheap susp. arms dont last 3 months ! If petrol model, the engines are prone to oil leaks (2.7 and 2.8) and they are rather complicated. There are twin lambda sensors, twin cats, coils wich fail regularly and o whole bunch of sensors. I would advise in getting someone with vag-com/VCDS to scan the car for you- could save you loads of money in repai bills later on ! From my point of view, the 2.5 tdi quattro 180Bhp is the best compromise between power and reliability (will return 40+ Mpg on a motorway trip) and the torque they provide from tickover. Throw a remap in the game and you'll be looking at 210-220 Bhp with no adverse fuel consumption. Be carefull though as the v6 tdi suffer from camshaft wear (especially if its been on Longlife servicing- walk away from those) and the injector pumps failure (cheap to sort out/refurbish by dieselbob for 550+ VAT but very expensive at dealer- 1500 quid + ). The clutch and gearbox are very strong so will take a lot of abuse but the flywheel will be on its last legs if the car has been chipped/remapped or towed with- look for bad vibrations at iddle with the engine hot and judder from clutch on take off. As i said, i'll be putting mine for sale soon so if interested drop me a pm for more details...w reg a6 avant 2.5 tdi quattro, british racing green, 180 Bhp sport, 6 speed manual gearbox, cruise control, dual climate control(usual refinements), sport recaro seats,4 electric windows,chequered fabric interior with no wear or tear, remote central locking, new clutch + flywheel, fully rebuilt engine (brand new cylinder heads, full cambelt kit fitted + water pump and thermostat+ a lot more). Everything is standard, only modifications are a allroad dual exit exhaust with exposed tailpipes (just like the facelifted models) and facelift rear bumper with s6 style rear valance/bumper trim and a slightly reduced compression ratio of the engine (helps with fuel consumption when cruising on motorway) so the car does a minimum of 500 miles on a tank full average- not bad for a 1.7 tonne barge wich can stretch its legs when booted. Only faults are a slow to close passenger front window (goes down nicely) wich migh need adjsuting and the dash is missing pixels- got worse since the cold spell but slightly better whith warm weather. The dash is a common failure on a6 but they cost 150 quid max to refurbish-do a google search... Be aware on wichever car you go for that the thermostat is a belt off job so, if the car does not warm up fully after a 10-20 miles motorway trip then the thermostat is stuck open and will need replacing wich cost big money applies to all v6 engines !
