Hello everyone. I have a new issue that just arose yesterday. Took my 2004 xj8 out for a nice drive and after like 15 minutes, out on a country road, I noticed my temp gauge had went from steady in the middle straight to the red zone so I pulled off and waited a few minutes then hit the key to see what the temp was doing. It was bright back to the middle but the fan was running. Parked and walked thru the park for awhile then drove home. The needle never really moved much again. I've noticed recently that just driving around the block with the engine cool, I'd pull back into the driveway and the fan was running. Can anyone give me any tips on what's going on here? Thanks, Larry. p.s. kinda concerned I may have a water pump issue as after flushing and filling I looked at the top b4 replacing cap and can't really notice or see that it's circulating the coolant, idk. always thought you could tell by looking for the movement and see that it was circulating but idk if that's true or not...ALSO lol, my enigine coolant keeps coming on and it seems to keep losing some coolant and I keep topping it off but I do not see any evidence that it's leaking out anywhere? headscrather lol.

 

You'll need to get the cooling system pressure tested. even if it's steaming from somewhere, there's no way you can see it as tight as everything is under there in front of the motor. Mine had a cracked radiator tank, right at the hose attachment, which led to a daisy-chain of replacing next-weakest-link, documented in the link in my sig.

It doesn't help that the underbody tray will catch drips, and any water that finally runs off of the tray won't be anywhere near the actual drip point. Finally, the valley hose is very a likely suspect piece. In my situation where I decided to replace EVERYTHING I could get at, the valley hose was the only one that was actually deteriorated to the point of obviously needing to be replaced. Of course, it's by far the most difficult hose to access, as the intake manifold MUST come off to get to it.

 

Thanks for the tips! First thing I did was order a pressure tester which is driving me nuts, waiting for it lol. And I had already removed the undercarriage tray while fixing the headlight issues and left it off until I was certain I didn't have any other issues to address b4 reinstalling it. Which of course I do lol. Thanks, Larry