Wait, Timing chain? I though these had a timing belt?!
The quick answer is Timing Chain. The B6/B7 S4 4.2 liter engine utilizes a chain driven timing system which is located on the backside of the engine facing the firewall. So, service position on a B6/B7 S4 does not mean removing the front clip, it requires engine removal unlike the older 4.2L V8’s found in the A8, A6 etc.
A question you might ask is: If this car doesn’t have a belt doesn’t the chain mean this is maintenance free? No it does not. You see, the timing chain itself may not really ever require replacement but its other parts that are a part of this timing system that are the weak points.
A quote straight from the Audi TSB on this issue
This noise is considered “normal” by Audi and claims this does not necessarily mean that you will need your timing system serviced soon. However, it does hint that your tensioners might be worn and in need of replacement.
Does this failure happen to all of the B6/B7 S4’s?
No, but take that answer with a grain of salt. No matter how many problems plague some engines, not all of them suffer from the same failures. No rhyme or reason to it, its just the way it is sometimes! When you think of how many S4’s were sold in the era between 2004 and 2007, only a portion of those cars had issues. But we also must come to grips with reality here, nothing lasts for ever. So now that these cars have surpassed the decade of age mark, things start to fail because well lets face it, mechanical items fail. Now these issues are starting to gain in popularity… and not in a good way.
I have heard all the rumors. Do these cars really have high dollar failures at or even before 100k miles?
There is no set mileage where failure is to be expected. We have seen some engines fail in as little as 40-50k miles and others well over 100k miles. There are a bunch of cars over 140k miles who have had no issues at all. But, are you willing to take that gamble? We have even had customers come to our shop requesting the full timing chain service with the threat of such failures. These owners typically don’t even have rattle at cold or warm start. The majority of the B6/B7 S4 we have take apart for this service, rattle or not has had broken timing chain guides. They are plastic and are resting in a high friction, high heat and high vibration environment. All things considered and the guides being made of plastic, you can certainly expect to see cracking.
Tips to ease the start-up rattle and to get the most out of your vital engine components
Tips to help prolong experiencing cold start rattle. You can also take this advice as increasing your chances of avoiding issues all together. Something that we cannot express enough, keeping up on maintenance.
- Frequent Oil Changes: Keeping your engine operating with clean oil is a benefit but not at all a solution but merely a piece to the puzzle in keeping your engines timing components in good working condition. This also isn’t going to change the fact that the timing chain guides crack either.
- High Quality Oil: The oil is the life blood of your motor like that of your veins. We highly recommend to use quality oil during oil changes. Our motors use 0w40 or 5w40. A couple popular brands include: LiquiMoly and Motul
- Proper Care: If you want the maximum life out of your motor you have to take the necessary steps to take care of it. Allow proper warm up, don’t beat on the car when it is cold and expect it to last forever. Keep up with scheduled maintenance and address issues as they arise.
What should i expect to pay?
The cost of having this job done is going to vary. Keep in mind this service is a very tedious and involved that should be completed by someone with plenty of experience. Our shop performs half a dozen if not more per year
The motor is out for the Timing Chain Service, what else should I do?
With the motor out of the car there is an opportunity to take care of maintenance, modifications, and other failing parts that are far easier with the motor out. Here are some items to consider. All of our timing chain service kits include the updated RS4 timing chain guide. This guide is still plastic, but is reinforced for superior longevity being less prone to cracking.
Contribution from Audizine member joeycuccaro and this thread.
Add on Maintenance and Performance Options.
- Clutch and Flywheel
- Motor Mounts
- Engine Components (Starter, Compressor, Alternator, PS Pump)
- Serpentine Belt and Tensioner
- Valve Cover Gaskets
- Spark Plugs
- JHM Headers / Aftermarket Downpipes
- JHM Intake Manifold / Spacers
- JHM Oil Cooler
- JHM Crank Pulley
- Snub Mount
- JHM Shifter Trio