944 S Models: Tech Notes
944 S Models Chain Tensioner
The timing belt on the 944 S models only drives one camshaft. A sprocket drives the other camshaft with a chain and hydraulic tensioner. The plastic ramps of the tensioner become grooved over time. The hydraulic tensioner will also retain less and less pressure, similar to a hydraulic lifter. While most owners tend to the timing and balance shaft belts regularly, they often forget (or simply don't know) about the need to inspect the chain and tensioner (after about 80,000 miles). Among other possible problems, chunks of plastic can come loose from the tensioner and lodge in the chain. Failure of the tensioner and/or chain almost always results in quite costly repairs. (It is necessary to replace the complete tensioner assembly as the plastic ramps are not available separately.)
Here is a prime example of a dangerously worn chain tensioner. The upper pad is completely missing and the chain wore halfway through the metal pad surface. Approximately 80% of the lower pad is missing. This tensioner had about 160,000 miles on it. It was finally examined due to noise symptoms, and replaced.
Chain tensioner kits can be purchased online from the following sites:
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