I have 1998 XJ8 3.2, that seems to have developed a small rattle.

It starts about a minute after startup, and lasts about 30 seconds or so and then disappears completely, until the next restart, then the same again.

I know the car has had a replacement engine fitted by jaguar, and has only covered approx 20,000 miles since then.

I have had the rocker covers off, and checked the tensioners fearing the worst, but they are the later metal bodied ones, and look in really good condition.

The noise appears to be coming from the front passenger side (driver side in the us).

The car drivers great, very smooth, no error's or warnings, but I do also seem to be loosing a very small amount of coolant over time, and there is a smell of it from the same area in the engine bay.

Could it be a water pump / tensioner ?

Or am I missing something completely obvious ?

 

Guessing VVT for rattle; although It may be the metal tensioners pumping up. Although stronger than gen II, not as sophisticated. Mine does it too and started after changing secondary tensioners.

Coolant leak will take some searching unless you are able to pressurize the cooling system. If smell is stronger in the front, check the water pump and TST housing. In the back, that funny hose . . .

 

I may be wrong, but I suppose the 3.2 engine has no VVT.
My personal experience with start up rattles is as follows: I got my xk8 with original plastic tensioners. The engine has been rattling since the first days of my ownership. At about 45000 miles I replaced the old tensioners with the metal ones. The old tensioners only had barely visible cracks that could not affect the functionality of the tensioners very much. When I had installed metal tensioners, all the rattles disappeared. But after a week of driving the same rattle came back. This rattle is not getting any worse, so I decided not worry about it any more.

 

As said there is no variable valve timing. Symptoms of that start sounds typical tensioners and chains.

If the expansion bottle is the original that would be the first place I would check. Usually at the back and is hard to see,starts as a small leak and grows. Easy one to remove and check too.

 

Can you be certain the primary tensioners were replaced?

 

Short of pulling the front apart to check the primaries, no, but as I said jaguar did replace the engine under warranty.