Review on Dorman 420-110 Timing Belt Tensioner: Optimal Engine Performance and Reliability by Ray Mcknight

I really only had to replace the o-ring on my timing chain tensioner but due Due to the high price, I decided to buy the tensioner complete. They usually leak as the seal ages. Remember that with the locking mechanism engaged you install two 10mm nuts and then turn the crankshaft a few turns with the crank bolt using a ratchet and socket wrench. You will hear the ratchet click a few times or more depending on timing chain play, mine clicked 3 or 4 times which lets me know the tensioner is fully adjusted. Do this before starting the vehicle to ensure the tensioner takes up any slack in the timing chain. When turning the engine by hand, a small locking lever releases the tension on the tensioner.