Hello,

I am new to this forum. Please bear with me for novice questions. Recently my 1998 XJ8L wit 120k miles, started rattling on start up. I thought it's just the cold weather and an ageing belt. But when browsed this forum i realized it might be the infamous tensioner issue. Can anyone please listen to this clip and confirm if it's the same? The sound vanishes once the vehicles moves 10,20 yards. Thanks.

Link : Jag rattle - YouTube

 

don't know about the rattle noise, I never heard one before my chain skipped, but that "diesel engine" sound of your is exactly the same that I had, and yes it's tensioners, that actualy is the sound when a bit loose primary chain slaps into chain guides...

 

Thanks for the reply.. How did you fix it? Is it an expensive fix?

 

I did the job myself so it wasn't expensive, but the job would cost me about 300 GBP (that's in my country) and the parts are about the same, you can check here- TIMING GEAR SERVICE KIT

 

Replacing the chain tensioners is not difficult. If you would change spark plugs or serpentine belt or water pump you will not have a problem with the tensioners. Total parts cost is under $200 but about $800 is the lowest you are going to get quoted at an indy, $1200 at a dealer.

You really need to do this TODAY as the penalty for skipped timing is a damaged engine. If you have the ability to do without the car I would not even start it again.

The Lincoln LS and Ford Thunderbird used the same (almost) engine for several years '00 and up so parts in Ford boxes are much less than Jaguar boxes with the same parts inside. Your car cannot use the valve cover gaskets from Ford but everything else fits.

Here are links to information on the work. Any questions just post back.

. . . and welcome to the forum!

Cam Chain Tensioners - Removing Valve Covers Only
https://www.jaguarforums.com/forum/j...17/#post316489

Cam Chain Tensioners
Help - sudden fail - Jaguar Forums - Jaguar Enthusiasts Forum
I just changed my own timing chain tensioners........ - Jaguar Forums - Jaguar Enthusiasts Forum
Ford tensioners for Jaguar??? - Jaguar Forums - Jaguar Enthusiasts Forum
Tensioners, when are they a "must replace" item? - Jaguar Forums - Jaguar Enthusiasts Forum
Free File Sharing Made Simple - MediaFire
DIY ~ Jaguar 4.0 (R&R) Timing belt, Tensioners, Water Pump, etc. - Calguns.net

Cam Chain Tensioners Lincoln LS Part Numbers
https://www.jaguarforums.com/forum/j...34/#post330655

 

Thank you. I see from the service records that primary chain and Timing chain were replaced long ago.. So I assume it would be metal tensioners now. Do they break as well like the plastic tensioners? From the sound clip, can the issue be confirmed?

 

I will use the current topic to ask few things related to the "rattle noise" and the tensioners that I never was able to figure out.
1. When the noise is coming from broken tensioners does the rattle sound appear only in the beginning (while idle after cold start) or it continues all the time - even when driving at high rev?
2. How can you check if the engine has skipped the timing?! Is it visible somehow when you open the cam covers? Does it have any symptoms?
3. Can tensioners bring to unstable work of the engine only after the start up and calm down after the engine is warm?!

 

First generation tensioners relied on oil pressure alone to keep the non-driven side of the chains tight. In December '98 Jaguar announced the 'second' generation tensioner which was nothing more than the original one with a spring installed to add some tension to the chain.

If you have the first generation the chain is slack until oil pressure builds up to the point of having designed tension on the chains. That is what causes the 'rattle' that goes away as pressure builds. Therefore, the 'rattle' is noticeable only on low oil pressure.

If you remove the valve covers and manually rotate (clockwise) the engine with a socket and breaker bar to the point that the cam flats are best aligned the right side will be almost aligned but both cams will be tilted to the center just a bit due to pressure from the valve springs. If you go past 'best' keep going, do not back up. The left side will be almost perfectly aligned.

The symptoms of a single tooth jump is running rough with no CEL/MIL codes or rough running with codes for misfires on one side. The symptom of a two tooth jump is bent valves and a ruined engine.

Failing tensioners can run for many miles due to significant oil pressure after warm up and above idle rpm's. They can also fail at any time, under any conditions.

First generation tensioners 'rattle' when failing, second generation may, or may not rattle. Both will destroy your engine. If you have either . . . change them or see the engine swap section.

 

MKK,

Sorry, I skipped you.

. . . replaced long ago . . . .

Many cars had the first generation tensioners replaced with the second generation ones. They fail at the same frequency as the first generation. Remove a valve cover and look for plastic tensioners.

Your '98 is a perfect candidate for having failing replaced second generation tensioners.

 

I'd second all of that above. It also seems to me (from reading your thread) that this 'noise' has happened quite suddenly. If that is the case something has had a sudden failure: use your pushbike to go & get the parts.

Seek out Brutal or motorcarman on this Forum to get advice as to where to go & what to get as replacement parts – the Ford Lincoln tensioners are a metal replacement which are much better, and check/replace the chains at the same time. Don’t cut corners to save a few bucks: you’ll end up spending more in the (short) long run. A good engineering supplies/workshop can make you very good quality ‘Morse’ or ‘Reynolds’ chains if one of the Forum Supporters cannot supply them.

And while you are there, check the thermostat housing for seepage. Originals are made of Bakelite and gradually warp. The problem is that the seepage evaporates before hitting the garage floor, so most times near complete failure is the first sign of a problem. If that happens on a freeway or similar a deep and abiding sorrow can set in to your wallet as well as your head. There is an aluminium ‘non-genuine’ replacement part available for the housing which overcomes the problem. And no, it is not made in China! Someone on the Forum was told by a Jag Dealer that the new (Bakelite) genuine parts are better than the originals & that the aluminium ones don’t fit properly etc. Utter crap. The only problem that aluminium suffers from is corrosion and that only if someone puts ‘additives’ into the cooling system which are not supposed to be there.

Cheers

Languid

Prevention is better than cure, and usually cheaper, too.

 

Thanks for all the reply guys.

I looked into the repair history. Metal tensioners were put in 2006. So i guess that would be the latest. In 2008, again the car was taken to a different service station for "noise under the hood on start up". they found the issue was with inner pulley and updated that as well. This service center has checked the tensioner as well and marked that they are updated.

I am going to open it up anyway. But collecting all the info I can before i jump in.

 

My 98 VDP had that same noise coming from the right bank forward side. Using a tube in the ear like a stethoscope i listened and pinpointed this noise coming from the forward cylinder area. Tapping/clicking noise was NOT coming from the "bulge" area under the valve cover where the tensioners are located. I changed the oil to the correct specs. Mobile 1 Full Synthetic 5w 30... Drove 40 miles and at the next cold start the knocking had stopped. Determined it was a sticky valve... I did pull the valve cover off to see those metal 3rd gen. tensioners with the white, or slightly orange oil colored slippers. Some would say add a can of detergent to quiet the valves down then change the oil. Remember to change that oil to manufacturers specs.