Just got my '99 XJ8 back from the shop. After figuring out that I was never going to find the time to change my tensioners, I found an independent Jag shop to do the job. When I picked the car up this afternoon, they showed me the parts they took out of the engine. The timing chains had begun to wear grooves in both secondary tensioners, and the tops were completely gone. I was literally one startup too many away from total catastrophe, and the car never showed any outward sign that the tensioners were gone (no ratlling, rough running or anything else). Both chain guides were cracked as well.

I sprung a coolant leak that I was never able to trace, which caused me to park the vehicle for an extended period. The leak turned out to be a split in the so-called Medusa hose (I had a complete hose kit put on while they had everything apart). Had that hose not blown when it did, I might well have trashed my engine without ever seeing it coming.

The moral of the story is this: If you own a Jag that has plastic tensioners and you plan to keep the car, replace them ASAP. I nearly learned the hard way.

 

That's what I love about Jags. You can actually celebrate a part failure that forces you to deal with another part failure. Where else can you get that?