First I want to point out that I have searched all over the forum and I did find a few posts about similar troubles. But the only useful one I read I can't seem to find again so here I am.

I have a 2004 Jaguar XJ8 (just bought it) with 165k miles and no service records (you wouldn't believe the deal I got) and it started making a loud metal clattering noise on startup when it was cold. It would warm up and go away and runs like a dream. It seems to be getting worse and it does it every startup now and has a faint clattering sound as it runs (enough to drive me insane).

I originally read about the plastic timing tensioners going out but that was supposed to have been fixed on this year of V8 (although I know it's still possible) but then I read that it could be the VVT (which is extremely expensive). Needless to say I have freaked myself out to the point where I'm afraid to drive the car now.

I read that the VVT issue isn't going to kill my engine but needs to be addressed if so and I was planning on cleaning the engine with some seafoam and replacing the oil with a good synthetic 5w-40 and better filter (whoever had it before me took it to Jiffy Lube last and I suspect they put the cheap non synthetic stuff in). But I feel like I may be waisting my time and should just replace everything to be safe (timing chains, guides, tensioners and possibly the VVTs). I found the kit for $300 on eBay for all the tensioners and timing chains but the VVT is a whole other beast (anybody know of a way to get them cheaper?) what should I do?

I can't sleep and need help... Thanks for taking the time to read this and thanks in advance for your advice/opinions 👍🏼

 

This happens to me when the engine sits and gets very cold, normally when its in the 30f and below region. Not very often in Texas mind.

Its like somebody hitting the aluminium engine with a hammer for about 5 secs in time with the engine turnover. As soon as I hear it happening, I run round to the lower front and try to isolate the area at fault, typically after a second it's already over. The air suspension faults also arrive around the same time too.

I searched online to see what it was too but could not find anything.

So I left it. 40K miles later, no issues but that isn't going to make the issue go away I know and it's colder for longer where you live and I presume that will make you a little more paranoid about it.

 

Yeah... It's been freezing here so that isn't helping. I decided to try the oil first. Yesterday I ran half a can of seafoam through oil system and put the other half in the fuel system. Then I drove it for about 150 miles. The noises were getting worse! It was knocking on startup even when it was warm and has that clatter sound when idling. Today i spent close to $90 on the best oil filter I could find and 7 qts of castrol full synthetic 5w-40 oil. I drained the old oil out (mind you it was less than 1000 miles old from jiffy lube) and it was black and filthy. I got the job done and started the car. First start it did the clunking for about 1-2 seconds then stopped. No more engine clatter. I let it run for about 10 minutes to circulate and shut the car off and started it again. No clunking or clatter. I've shut the car off and on about 10 times since and nothing!!!

I'm really hoping I got lucky here. But I'm going to drive it for a few days and see what happens next.

 

Yes, let us know, don't leave us hanging. I, too, get a clicking noise when I first start the car (sounds like a sticky hydraulic lifter) but always goes away within 15 seconds of starting a cold car. I learned to ignore it. May be i'll run some Marvel Mystery oil in the crankcase at some point.

 

Please could someone explain to me why I keep reading about 5W-40 synthetic oil for a 2004 XJ8, when the Owners Handbook clearly states the use of synthetic 5W-30?
Have I got this wrong, please?
Regards,
Ray

 

Mine does the same thing at the same mileage under the same conditions. I've owned the car since it had 117k and it has always done it. At 165k I'm giving my 2004 a free pass to make whatever the hell noise it wants to as long as it starts, runs and gets me to work everyday. Old cats get grumpy in the cold weather. I run Motorcraft Synthetic Blend 5W30 because I feel like it treats old seals pretty well while still providing many benefits of synthetic oil.

 

If you've checked for your rather hot area then go with what the manual says. (Usually it lists more than one as OK.)

I think you'll be somewhere that the jag servicing schedule calls "arduous" and wants various extras every 6 months.

 

Have you use stethoscop to isolate the noise? I don't think it's the noise from timing belt tensioner, but you have a bad serpentine belt tensioner.