Continues off and on for about 30 seconds, then all is well. Drove car and no noise on warm start. Car has 43,000 miles with secondary tensioners replaced at 25,000 miles, to be on the safe side. Not sure if I should tow or assume it's starter or water pump, and just drive to repair shop?

 

Vvt? Lower chain guide? Your right Water pump is probably a good suspect.

 

Have someone start it cold while you stand ready with your stethoscope. And maybe you'll catch it! The shop will have as hard a time locating it as you will.

 

Perhaps only continues until oil pressure builds up. Are you using an oil filter with a non-return valve like the OE Jaguar filter? Filters without a valve allow the oil to drain into the oil pan as the engine cools down. On a cold start, the filter has to refill before pressure builds up to normal.

Any starter motor sourced noise should cease when the engine fires. Worn water pump bearings usually squeal rather than make metallic noise.

Serpentine belt tensioner is another possibility.

Graham

 

What car are discussing????????????????????
AJ26 or AJ27??????????????????
More info please.

The AJ26 is known to actuate the VVT every so often at idle (CLACK). I can't remember if it was a TSB or a TECH TIP. Maybe we discussed it in a Jaguar training class??

bob

 

I had that sound you describe..
Cold start. metallic sound, would then go away...

Turned out to be the tensioner pulley AND the idler pulley .
Pull the belt and start it up..Good place to start in my opinion, and a cheap fix.

 

+1

Mike,

I can see you have put Vehicle Details in your forum Signature (mick99 1999 xk8 convertible) but have then chosen NOT to display this in your post #1.

As a Moderator, I can check your profile to see all your details but members can't do this. Please include your Signature in future posts.

Graham

 

+1 on the idler pulley. Youd be surprised how many different noises they make when bad. Easy check. Release belt tension spin pulley by hand. It should be smooth. Mine gave a stuttering ratchet feeling when defective.

John

 

3 days later, no noise on cold start! ..Does that eliminate any possible causes?

 

I agree on idler pulley. If it gets worse on cold days, a sure bet.

 

Here's what my car sounded like on cold start.. I dreaded the worst..
It was loud and metallic.

Turned out to be the pulley.