01VQ20DE Timing Chain Tensioner Wear
The hydraulic timing chain tensioner on the VQ20DE loses clamping force as internal seals degrade with age and oil degradation. This allows chain slack, producing a cold-start rattle that persists for several seconds. Continued operation causes the guide rail to wear through, and in advanced cases the chain can jump a tooth or contact the timing cover. The VQ20DE uses a smaller tensioner than its VQ30 sibling and is more susceptible to failure at high mileage.
Symptoms to notice
What to check
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