Jaguar 1998 Xj8 Noise on startup

1998 JAGUAR XJ8
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TJ1511
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I have a 1998 XJ8. I hear a knocking noise (valve lifter noise) at start-up. If I rev the motor to about 1500 rpm to 2000 rpm or start moving it goes away. It always happens. I mentioned it to the dealer and they said it would be a lot of money to look into.

I have also read a few forums and all I can find is "It sounds to me like the timing chain tensioner(s) are sticking, making the timing chain loose, at higher revs the tensioner becomes unstuck (the clunk sound) and releases, tightening the chain and ending the noise. It is not normal, the tensioners may not have been installed correctly or they may be sticking because they are dirty".

Before I spend the money to look into this I would love to know what might be wrong.

Any assistance would be appreciated
Oct 9, 2006 at 4:20 PM
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K_R_GARRETT
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Hello, I posted the question below yours regarding the noise on start up on a 1995 XJR. My mechanic is almost positive that the problem is the tensioner for the timing chain. He told me that the parts would be around $80 and that it would require 1.5 hours labor. I have an appointment later this week to have the work completed. I will let you know if it solves the noise.
Oct 10, 2006 at 5:29 PM
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TJ1511
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Thanks and let me know.
Oct 11, 2006 at 1:11 PM
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K_R_GARRETT
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Today I picked up my Jaguar and the problem has been fixed. The noise I was hearing was being caused by the timing chain tensioner failing. I was told that the new tensioner was a slightly different design than the old. I am unsure what year Jaguar made this change but I assume the old design was flawed.
Oct 13, 2006 at 4:51 PM
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3TOMMY
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get the tensioners changed asap, or your gonna roast the engine like we did, its really messed up, but if the tensioner breaks, you need to replace a lot more. and regarding the $100 part, and 1.5 hours labour, i think its for 1 tensioner. and there are several, i cant remember exactly how many. but you might wanna change more than one, if the mechanic is bothering to open the whole thing up anyway. also, you will need to hcange the headgasket, when you open it most likely, so bye bye another $100. the plastic tensioners get brittle and snap, so be careful guys.
Nov 23, 2007 at 1:36 AM