How to Adjust an Overly Tight Timing Belt?
2 Answers
Timing belts can be adjusted using a hex key. The optimal tension is achieved when the belt can be pressed down with 10mm of play, flipped 90 degrees, and the engine runs normally without any abnormal noises. The steps for inspecting a timing belt are as follows: 1. First disconnect the negative battery cable, then disconnect the positive cable. 2. Unplug the alternator's electrical connector, then remove the engine wiring harness from the cylinder head and take off the cylinder head cover. 3. Remove the upper timing belt cover. 4. Rotate the crankshaft pulley counterclockwise and check the belt for cracks or stains from oil or coolant, which should be thoroughly cleaned if present; inspect the belt teeth for wear and replace if necessary.
Adjusting the timing belt too tight requires proper technique. I've experienced this situation several times and found that an overly tight belt increases bearing wear and may even snap the belt, causing internal engine damage. When handling it, first park the car securely and turn off the engine, allowing all components to cool for at least half an hour. Then open the hood, locate the timing belt cover, and remove it. Find the tensioner device, which could be a pulley or gear, and loosen its fixing bolt without removing it completely. After letting the tension adjust naturally, check the belt tension standard—usually pushing the midpoint of the belt should result in 10-15mm of sag. If you don't have a tension gauge, manually press it to feel if the elasticity recovers quickly—that means it's OK. If it's too tight, slightly adjust the tensioner position, slide it to the appropriate spot, and then tighten the bolt. After finishing, start the engine and listen for any reduction in noise. I strongly advise against doing it yourself unless you're experienced; it's safer to have a professional shop use specialized tools. Otherwise, improper adjustment could lead to more serious issues. Regularly check the belt condition during every 50,000 km maintenance to avoid aging-related problems.
