Q: I'm looking for a quote to replace the timing chain on a S4 4.2L

Hi there, thanks for writing in. He was correct in saying that the chains are on the back of the motor. The engine and transmission must be removed completely, then separated form one another on a workbench, where the chains can then be replaced. The chains on your car are extremely labor intensive to replace, and because of that, the price is usually very high. Depending on whether just the chain guides are replaced, or everything timing chain related is replaced, the price can vary quite a bit, but starts at several thousand for most reputable technicians. Jobs that require engine removal cannot be performed on a mobile setting, so you will need to find a traditional shop or dealership that you trust, or consider getting rid of the car and replacing it with another one. The chains are a common failure point on these early V8 S4’s and many cars get dumped due to failing chains.