WHAT TO LOOK FOR
The Quattro’s in-line fifive-cylinder engine was built in three forms; 10-valve 2144cc WR, 2226cc 10-valve MB (from 1987) and the 2226cc 20-valve RR (from 1989). Most troublesome is the WR, most reliable is the RR (but it has the priciest parts). The MB gives the best balance of cost and reliability. Engine rebuilds are expensive, but if looked after a WR unit will do 150,000 miles; the MB and RR units will give at least another 50,000 miles. A synthetic oil change is needed every 5000 miles, along with Audi oil filters (WR engines have two), complete with non–return valves. The cylinder walls erode and become oval. Once worn, a rebore using a new set of pistons (£750) is the only sensible alternative. Key WR weak spots include a failed turbocharger, given away by poor performance and blue exhaust smoke.
Rebuilds and parts
Ticking from the exhaust manifold as the engine warms up indicates a cracked manifold, with replacements unobtainable. There aren’t any problems specific to the MB or RR engines, but all three units can suffer worn valve guides and hardened valve seals, given away by blue exhaust smoke on the over-run. If the engine has been thrashed, a top-end rebuild could be needed in just 60,000 miles, costing up to £1300. Look behind the offside corner of the front air dam, at the oil cooler and the unions on its pipes. These corrode, leading to oil leaks. If the engine runs badly or won’t start, check the boost gauge. A permanently high reading means the inlet manifold pressure sensor has packed up; replacements are £150 and fitting is easy. The cambelt should be replaced every 45,000 miles or fifive years, but it’s not that straightforward so it’s often overlooked.
The transmission is incredibly durable. The synchromesh wears eventually and with a gearbox rebuild typically £1000, most owners live with it or fifit a used gearbox for around £300, plus 10-12 hours’ labour to fifit. Clutches typically last 150,000 miles, but if abused they can last much less, so check for slip. Check the pneumatically operated diff locks haven’t seized up; activate the switch in the centre console, then ensure the light on the dash has lit up to say they’re activated. If not, they’ll need freeing off and lubricating; an easy job.
The suspension bushes wear with the front and rear subframe bushes bearing the brunt, along with the wishbone bushes. A new poly wishbone bush set is £100 and they’re an easy swap. Abused 20v Quattros can suffer from a cracked rear subframe; replacements are £800. Vague steering and uneven tyre wear suggests the wheels are out of alignment; each corner can be adjusted for camber and toe in/toe out.
On MB and RR models, pull the connectors off the low servo pressure warning switch mounted on the brake servo. With the engine switched off, but the ignition on, attach a continuity tester. Press the brake pedal repeatedly on a 2-3 second cycle – if the switch closes after fifive or fewer depressions the braking system’s hydraulic accumulator has failed; new ones are £250.
The most common problem with the earliest cars is corroded connections. Tracing dodgy connections can be a pain, so check the fusebox, which can crack. New interior trim is extinct, so it’s worth paying a premium for a car with a really good cabin. Most parts are available on a used basis though.
Pre-galvanised Quattros suffer from corrosion around the windscreen, on the boot floor and in the inner sills. Take proper care and attention to properly inspect for accident damage too – rust on late cars points to poor repairs.