The other day I went over a bump in the road in my XKR and I heard an expensive sounding "crack".

Visual inspection revealed nothing, but when I got going I heard an expensive sounding "whine". It was pretty well suppressed when driving at speed, noticeable at low speed, and very obvious when the hood is up.

When I was driving the pitch of the noise did not seem to change much - but can't be certain as at higher speeds the noise was inaudible.

Temperature and oil pressure were normal


I have attached a copy of a video and a link to the same video.

From these sketchy details, can you get any idea of what it is? The car drove OK on the way home - but is it really driveable?

 

https://photos.app.goo.gl/RCMAjFnTR2GDrvUr9

Link to same file (might not be allowed...)

 

Hard to tell from the audio, but a high pitched whine that doesn't change with rpm sounds more like a vacuum leak.
When you shut off the engine does the sound die down instantly, or linger for a moment after the engine quits?

 

Paddy - that's some whine! From your mpeg, you can't really tell where the noise is coming from.

Hmmm, I don't have the supercharged engine, so can't really advise on any potential air leak somewhere, as advised above.

But, long shot, try removing the serpentine belt (2min job) and briefly run the engine. That'll check for any potential grumbly pullies.

Another long shot, is to unplug both fan motors and run again.

If it's an internal component to the engine ie crank shaft journal bearing etc, it's going to be expensive! But noise should change with RPM so unlikely. However if it's that, that'll be worthy of a "Whinge!"

 

Wrong trhead....

 

Thanks mhminnich, It stops when the engine's off.

 

Thanks David. My formerly local (they moved miles away without me knowing) jag specialists viewed the video and think it may be a drive belt tensioner and that I should not drive it...

If I am feeling brave, I may do as you suggest....

Regards

DC

 

The drive belt idler pulley bearings can go bad. There are some posts with links to buying a non-oem replacement which will save you a few $$$. You should be able to find multiple posts on the subject with a search.

 

I'm going to go on a limb and say it it is the intercooler water pump. It's electrical, and sounds a bit like that, but normally a lot quieter.

Does it make the noise with the key in position 2 and the engine not running?

Two suggestions:
1) Massage the hoses that go to it. If you get an air bubble in there somehow (like when draining the coolign system) they can make an awful noise.
2) Try unplugging the electrical connector and see if the noise goes away.

 

An easy way to locate the noise is to use a piece of garden hose with a funnel on one end to your ear. Just be careful the hose doesn't get between the pulleys and belt.

 

Thank you.

 

Thanks Charlie. No noise when it is in position 2. Regards DC