The Top Two Reasons Timing Chains Need Replacement

Timing chains don’t get a lot of attention – mostly because they are intended to perform for the life of the vehicle. But as vehicles continue to last longer, timing chain repair is becoming more common. That’s because eventually over time, the chains will wear out and cause one of two issues that flag a replacement might be needed.

• Reason 1 for Timing Chain Repair – Noise
  A vehicle owner or technician might notice considerable noise coming from the front of the engine, especially upon warm up. This is an indication that the timing chain guides and tensioners are worn past the service life. We strongly recommend a technician perform the following diagnostics BEFORE determining if a timing chain repair is necessary.
  First, inspect the engine. Then, review oil change maintenance with the owner – a vehicle needs to have had regular oil changes. Finally, remove at least one valve cover and inspect it for sludge and carbon deposits. If the inside of the engine is clean, a quick compression and leak down test can verify engine integrity. As long as everything comes back clear, a tech should move forward with timing chain replacement.
  However, if the engine is showing signs of sludge and deposits, it is not a candidate for timing chain kit replacement, as the customer likely needs a new engine.

• Reason 2 for Timing Chain Repair – Chain Stretch
  A system that is experiencing chain stretch will usually trigger a PCM code, like P0016 or another code related to cam/crank correlation. Before recommending a timing chain kit replacement, it’s critical that a technician first diagnoses and repairs the codes, and verifies that the cam/crank sensors in question are functioning properly. The VVT solenoids also need to be inspected.
  Once you have verified the integrity and function of crank, cam and other sensors related to the engine timing system, it is safe to proceed replacing the timing chain system. Our team has seen timing chains replaced only to find poor connections or non-functioning sensors as the actual cause of the PCM code.