Engine Belts And Pulleys problems of the 2000 Jaguar Vanden Plas

There exists a condition with the secondary timing chain tensioner in 2000 Jaguar xj8, Vanden Plas, or xk8 models that can and does lead to catastrophic engine failure. To date Jaguar does not admit that this is a serious design flaw and safety issue. There are no recalls or even a service bulletin on this however failures are documented on the Jaguar club of north America and possibly others have been quietly fixed by Jaguar. This plastic tensioner can fail upon start-up, as it did in my case, or in the worst scenario it can happen at speed. The plastic housing of the tensioner simply fails resulting in the timing belt breaking and or jumping off. Without any warning the result at speed is sudden and complete engine failure, which can lead to an extremely dangerous driving condition. At startup the result is the inability to start the engine stranding the driver wherever the car has stopped. In my case the failure occurred on startup, breaking the timing chain, and resulting in a $2000 repair. The car was a 2000 Vanden Plas, VIN sajda24c5ylf04959, with 42,067 miles and failed without any previous noise or indication. Upon engine tear down to repair there was no apparent sign of excessive wear or any oil sludge. The failed tensioner plastic housing simply broke. The other good tensioner had a clearly visible crack in the plastic housing and indeed would have also failed. I have the failed parts. Replaced was: secondary chain, both chain tensioners, boss seal, 2 timing seals, and 2 cam gaskets. (failure at speed requires complete engine replacement. ) pictures are shown below.