Used car buying guide: Audi S4 (B6 / B7) Car News

“The Audi S4 you should never buy,” shouts an article about the Audi S4 B6 and B7 generations. It’s not an encouraging start for a dedicated model buying guide, but it’s best to tackle that load right away.

It refers to the fact that the engine has a timing chain rather than a timing belt. No problem there, given the reputation of chains that outlast belts, except that on the S4 the chain guides and tensioner are plastic. From about 100,000 miles, the material breaks down. Impending failure is signaled by what victims call the “death rattle” when the tensioner slackens and the chain begins to wander before, in the worst case, pops out of the teeth and, well, you know the trick. after. Get there early enough and you can replace the tensioner kit, but it’s off-engine work so it’s expensive. Budget around £ 2,500.

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The S4 you should never buy indeed, except that many B6s and B7s have been through life without even a glance of the chain. Check their service histories and you will find that they have been treated to regular 0w40 or 5w40 grade oil changes. Either way, this kind of problem can be overkill and you wouldn’t want it to spoil the fun of finding a good S4, especially since it comes with one of those rare things: a naturally aspirated V8.

It was launched in 2003 in sedan, convertible and station wagon bodies (Avant). The 4.2-liter all-alloy engine produces 339 hp at 7,000 rpm and less screaming 302 lb-ft of torque at 3,500 rpm. Equipped with the standard Getrag six-speed manual gearbox (there’s a ZF automatic with optional paddles), an S4 can speed the 0-100 km / h sprint in 5.0 seconds. Quattro four-wheel drive and an electronic differential lock should take some of the credit here. As the revs rise, the engine makes a hoarse howl. This is the heart of the car and the reason why you would buy an S4 B6 or B7-gen.

The B6 S4 is the first generation, and it was replaced in 2005 by the B7. The engine and performance remained unchanged, but the suspension was changed and in 2007 the Torsen center differential was updated. At the rear, quad tailpipes appear. Both generations have ventilated discs all around and speed-sensitive power steering. The latter looks pretty natural but is wasted slightly on a private car of entertainment value by a quattro system that favors the front wheels over the rear. Again, that’s why this engine is the star of the show.

When you start looking for an S4, you’ll find that there are twice as many automations as the manuals, but expect a manual because it’s a nifty setup that also offers much-needed additional driver engagement – in addition, it is easier to play songs with the motor. The mirrors are real alloy on early cars (check for damage as they are expensive) and the seats are from Recaro. The B7s added a Bose stereo. Sedans are the most common, convertibles are fun, and Avants are as rare as houndstooth. Classic status beckons you, so don’t hang around.

How to get one in your garage

An expert’s point of view

Peter Macejka, Audi VW Specialist Center: “The B6 / B7 V8 is a good engine and sounds good, but it could do with more horsepower. The 414 hp BS7 RS4, which uses a highly modified version of the S4’s 4.2-liter V8 engine, is more exciting. But this car is much more expensive. The big problem with the S4 is the timing chain, or rather the tensioner and plastic guides, which break after many heat cycles. In fact, we have an engine here on the bench fitted with a new tensioner kit. The RS4 uses a tensioner and steel guides, so that’s not a problem. Another weak point of the S4 is the rocker cover gasket. It weakens over time and allows oil to flow onto the engine. It’s messy but easy to spot.

Buyer beware …

Engine: With the engine cold started, listen for the rattling of the timing chain. Check the service history for regular oil changes, being wary of cars that have had extended service intervals. Inspect the oil level as it may drop due to a failure of the PCV (positive crankcase ventilation) valve or, worse, scratched cylinder walls. The misfires could be faulty batteries.

Power steering: Check the condition of the steering pump hoses, which run near the engine and can develop leaks. A pump deprived of liquid destroys itself quickly. It’s located at the back of the engine, so replacing it doesn’t come cheap.

Transmission: Cycle through manual or automatic gears, feeling smooth and hassle-free changes. The clutch (it typically fails around 100,000 miles), flywheel and torque converter issues are not unheard of. Have the automatic transmission fluid changed immediately as it is unlikely to have ever been refreshed. Also have the rear differential oil changed.

Brakes and suspensions: Check…