The Audi S4 is the high-performance variant to the brand’s more plebeian counterpart, the Audi A4. The Audi S4 first appeared in North America in 1992. Back then, it had a bi-turbo 2.7-liter V6 under the hood and was, and likely forever, be one of the most sought-after S4 models on the market.
For the next two generations of the S4 (B6/B7, 2003-2009), the Audi S4 was completely refreshed and the bi-turbo V6 was replaced with a 4.2-liter V8 engine that produced 340 horsepower and 302 lb-ft of torque. The bigger engine was able to get the car to 60 mph in about 5 seconds and was a worthy replacement, in theory.
Over time, this beautiful V8 would eventually rear its ugly head in the form of maintenance issues. Leading any uninformed prospective buyers of the B6/B7 Audi S4 to ask, “How bad could it be?”
It’s bad, very bad
A sedan or convertible with a V8 engine and all-wheel drive sounds fantastic on paper and it may be tempting to buy an Audi S4 from this generation. In fact, a quick nationwide search on Cargurus.com for a 2003-2009 Audi S4 will net results with prices in the sub-$10,000 range, even as low as $5,000, depending on the mileage. However, buying one of these cars would be like getting a screaming deal on a house not knowing that it’s the most haunted house in America.
The main issue is that when Audi designed the 4.2 V8 engine, they used a timing chain instead of a timing belt. The chain itself wasn’t the issue, though, as it was meant to be “maintenance-free.” The kicker is that they used plastic timing chain guides and tensioners that keep the timing chain in motion when the engine was on. As you could probably guess, the heat and friction over time would cause these plastic parts to eventually break.
The only audible symptom of this major issue would be a rattle from the engine, which some enthusiasts aptly call “the death rattle.” Upon diagnosing the issue, it would mean that everything involving the timing chain would need to be replaced.
That doesn’t sound that bad
On any other car, a typical timing belt/chain service would be pretty easy; just move some stuff out of the way and replace the parts. Unfortunately, the timing chain assembly in the B6/B7 Audi S4 is located in the back of the engine, right up against the firewall. In order to replace it, the entire engine needs to be dropped out of the car. If you get this done at a dealer or even an independent shop, expect to pay anywhere from $5,000 to $8,000 for the service. An average garage mechanic could tackle the job, but the parts alone cost about $3,000.
How do you like that Audi S4 now?
This issue might sound terrible, and technically, it really is. It doesn’t take much to find the horror stories, just type “Audi S4 timing chain issue” into Google and have fun reading. If that’s no convincing enough, Carcomplaints.com ranks the 2005 Audi S4 as the number one car with the “Worst Audi S4 problems” noting the main issue as “engine rattle on start up.” Of course, if none of the literature you read stops you from buying one of these S4 models, just make sure you can afford the cost of this major service.
If you don’t have the funds, then we suggest staying away from it.