2003 XK8 w 93k miles.

For several months now the engine is making a moaning, groaning, growling noise. It varies w the RPM and is detectable at lower speeds but wind noise drowns it out at higher speeds. It's not getting worse, it just suddenly appeared maybe 20,000 miles ago. It runs perfectly and has good power. Just a low level noise.

An indy mechanic doing other work said he felt a little vibration on the oil lines and deducted it MIGHT be the oil pump. I've been reading this forum and the XJ8 forum for years and never heard of an oil pump doing this.

Being a 2003 it has the upgraded cam chain tensioners. The serp belt tensioner was replaced a few thousand miles ago.

Any ideas? Thanks.

 

Hi Norm

Are you able to get a video to hear the noise at idle and when revving, etc?

Have you had a listen around the engine area, coming from top, bottom, left or right, etc. ( Possibility idler pulley or water pump pulley for example )

And this is only coming from the engine, and not anywhere else while driving?

 

I'll see if I can post a video of it tomorrow. I put my stethoscope on it about a year ago and thought it was coming from the serp tensioner. The serp tensioner indeed was bad but that wasn't the problem. I'll post tomorrow if I have time. Thanks.

 

Do you still have the belt tensioner with the plastic pulley or metal one, the idler pulley should have been updated to the metal one as well.

Have you also tried removing the belt and starting the engine to see if the noise goes away?

As for the oil pump - I've never seen an oil pump fail on these engines, not to say it couldn't happen. They are pretty basic in nature how they operate.

 

The belt tensioner was replaced with the OEM part a few months ago so I assume it was the latest edition (my indy did the work).

Indy removed the belt and the noise still persisted.

I agree about the oil pump.

Thanks.

 

When you had the chain tensioners replaced, was it just the secondary chain tensioners, or was everything replaced ( primary chains & secondary chains, guids, etc. )

 

I had the serpentine belt tensioner replaced as it was noisy. The cam chain tensioners are stock. My understanding is that the 2003 models did away with the plastic cam tensioners.

 

Ok, the Jag dealership says the noise is from oil caveating in the oil lines leading to and from the oil cooler. The oil lines are aftermarket (due to a leak) BUT my wife was complaining of the noise while the car still had the OEM lines.

I'm having a hard time believing cavitation in oil lines to the oil cooler could be the source of the whining noise. ? ?

 

Not sure how the pickup works on 4.2, my Land Rover 4.0 motor has two bolts, the bolts can loosen and you will siphon air at the pickup, that’s the only way I could imagine. I thought the jag 4.2 lines are pressurized , so wouldn’t you simply have a leak instead?