I'm picking up our new (to us) 2001 xk8 tomorrow in Daytona Beach
and driving home. I've read enough about the timing chain secondary tensioners
to be totally freaked. The car has 33500 miles on it. How fast do I have to
get the tensioners replaced?

 

Most secondary [and primary] chain or tensioner failures which I have read about do not occur until after owners have first heard the characteristic tensioner/chain rattle of death on cold startups. It sounds like a battleship dropping the anchor. AT 35K miles, I would not be overly concerned about the tensioners; certainly not on the drive home.

If it were my new purchase, I would take some time to simply drive it around and enjoy it in order to uncover any other defects or problems. After you have made up a work list, then take the car to a couple of independent Jag specialists and obtain a quote to get all the work done at one time. The work list should include any problems you have uncovered plus all the fixes to upgrade the items you know you'll need, like metal thermostat housing and metal tensioners. That way your labor costs will be minimized.

If you are really freaked out about this... give Bob Sellers a call and bring the car around to him. He'll give you a quick inspection, listen for signs of trouble and won't overcharge you for anything. He's a great guy fixing Jags for 30 years. Here's his link w/ map.

http://maps.google.com/maps?oe=utf-8&rls=org.mozilla:en-USfficial&client=firefox-a&um=1&ie=UTF-8&q=bob+sellers+daytona&fb=1&split=1&a mp;view=text&latlng=14539167556457835936


gordo

 

Good advice Gordo. Thanks! By the way, I talked to Bob Sellers and
am taking the car over to him after we pick it up.

 

I had my tensioners (upper & lower) replaced about 9 months ago at 61K miles. The uppers had a slight beginning crack and the lowers were totally intact. I don't think you have anything to worry about real soon.

 

at 101,000 miles my 2 generation "red plastic" secondary tensioner's were about to fall apart. and the Primaries were fine.

 

Picked the car up yesterday and took it straight to Bob Sellers. He said it sounded OK but to be sure they'd have to remove the valve covers. I decided to chance it and drive home to Port St Lucie from Daytona. Took US1 the whole way and what a ride!! The car is amazing. I'll deal with the tensioners as soon as I find a mechanic around here. However, if I ever have trouble near Daytona, the car's going to Sellers. Smart guy who obviously knows Jaguars.

 

Don't fix what isn't broken - the tensioners willwill let you know when they need replacing. It's not a catastrophic failure anyway, you'll hear the need in plenty of time.

Enjoy the car!

 

Hi Spurlee,

Inmy shop aretwo destroyed AJ27 engine blocks, both with destroyed left cylinder heads, both from 2000 model year XJ8. At 105K on the first, and 96K on the second, the respective secondary timing chain tensioners failed andeach broke a secondary timing chain. Presumably these failures occurred at higher engine RPM, as the openexhaust valve pairs on each engine smashed their respective piston crownand deformed the piston so badly that the respective bore was damaged. The broken valve heads also seriously gouged the combustion chamber of the affected cylinder in each of the two junk heads.

I have not had the experience of operating a Jaguar V8 at the time of a tensioner failure or secondary chain break, but I have read reports by others who claim to have not heard any advance warning. The two extreme cases I cited were probably operated by their drivers until they ground to a halt: I have repaired other engines were valve damage occurred from the same failure, but the piston crowns were barely marked. Many times the chain breaks and no valve damage at all occurs.

So I can't say with certainty that your first point is correct, though I have heard many engines with chain noise that had not yet suffered a failure. I can say with certainty that catastrophic failure can and does occur as a result of secondary timing chain failures in some instances.

 

Spurlee,
I took the car to a mechanic yesterday who specializes in Jaguars. He said That the problems was far less common in the 2001 models and with only 33500 miles, I had some time before I needed to worry about it. I figure I'll probably get it done before 40K.

 

If the build date of the engine (engine number) is late enough in '01, then yours already has the latest style tensioners and is not anything to worry about. If not, a guess that 99% of the earlier tensioners last 40K miles is probably close. I know of one '97 that broke at 37K.

 

Chazaroo - That's good. Just don't run it into the ground after you hear them asking to be replaced and you'll be fine.

 

Hi Jagtech...

Would you happen to know the cut-off number (date) when they started using the latest style tensioners?

Thanks...

 

The conversion to the metal bodied tensioners is reported to be on August 13, 2001. Thus an engine serial number 010813XXXX or later. That is sorta the start of '02 MY production. However, it is not totally true that all '02 cars had the metal tensioners. My '02, by VIN and EPA certification, was manufactured in June of '01. By inspection it has the red plastic, spring assisted tensioners. The manufacture date is displayed on the driver side (US) 'B' column label. If your manufacturer date is close to the change over an inspection is in order. Assembled engines moved into vehicle production in an undocumented manner.

Your dealer can provide your engine serial number via VIN look up as reading it is very difficult.

Reports on this forum and others would indicate that the chain 'rattle' was, at least to some part, eliminated by the spring assist of the '2nd generation' tensioners. Reports of their failure involved the 'slippers' coming apart and causing chains to break.

Today is the day to change my tensioners. Bought them from the Ford store for about half the price of any Jaguar source and the Ford box had 'JAG' after the part number.

Wish me luck.

 

Well, a few hours later and the new tensioners are in. The right one was cracked about 3/8". All slippers and the left one looked good. That is in 8 years and 47k miles with well documented maintainence and no overheating/waterpump/thermostat issues in its history. It would probably have lasted many thousands of miles more but might not have.

I feel better anyway. Besides I got to join the 'did it myself' club.

 

That is one DIY club I rather not belong too.