Yeah, it’s a partial fix. For a keeper, replacing everything (4 metal tensioners, new chains, guides, etc ) is the only way to go. My 2000 XK8 (75k) runs great w/ no cold start noise or chain slap but am shopping for a 2003-2006, I’d like to enjoy my 1st Jag w/o wondering if the engine is going to grenade. Cost for 4 tensioners is 3,200 - 4,000 DIY (2 or 4) isn't really an option for me. If I have just the uppers done, will pull the pan to clean out the plastic bits.

If you’ve replaced just upper tensioners (w metal), does the engine run well? What was the mileage?
How many miles driven (no problems) since the repair?
If the engine broke, what was the mileage? What happened?
Was there any advance warning (cold start noise, chain slap, credit card company raised your limit w/o request)?
Other comments?

Thanks

 

I changed just the uppers on six cars with anywhere from 50-140K mi. and none of them had a problem. The primaries are less likely to fail, but the guides could break up and clog the pick up screen, but it isn't a common problem like secondary failure.

 

Thanks. Much appreciated. If I find secondaries are missing bits, check for plastic at the pickup screen? Is pulling the pan a major project?

 

I've done in the neighborhood of about 50-60 cars for timing chains ( dealer tech ). I can say from the ones I've done, only had 1 ( XJR ) where the primary tensioner failed. Primary ones will most likely give you notice they are about to fail, such as the one I had, which was a loud knocking noise from front timing cover.

You can get away with just changing the secondary ones, but keep in mind that the all the guides and primary tensioners are still plastic. They will eventually fail. Depending on how many miles you have, how often you service, etc. will affect the remaining life. As it was mentioned, if you're planning on keeping it, replace everything. Make sure you lock the flywheel in place if you do the whole job, that crank bolt is tight, risk damaging the VVT units trying to loosen the crank bolt. There are special tools on the market, but if you're able to improvise, more power to you.

As for removing the oil pan, on the XK it depends whether you have the coupe or convertible. If you have convertible, you'll need to loosen one of the lower braces and slide out of the way to lower the oil pan.

 

I did just my uppers, got tired of the paranoia. The pads had disintegrated on the piston end of both and were wearing on the steel. I could slightly hear the slop on cold start. Car actually runs about the same when warm. Biggest improvement was changing the valve cover gaskets, since my plug well seals were seeping and causing misfires periodically between me cleaning out the wells.

 

Thanks for the feedback. Glad it worked out. Agree on the paranoia. Also a lot cheaper (or easier) to do uppers than repair or replace the engine.

 

I recently replaced the tensioners on my wife's xj8. There was a noise coming from the front of the engine. I thought it was the water pump so I took off the serpentine belt and the noise was still there with the engine running. Took the cam covers off and one of the guides didn't look right. Took the timing cover off and the photos show what I found.



One of the guides was completely gone. There was no engine damage and it ran fine.
If you only do secondaries take a light and check the giudes for cracks. I have had 4 or 5 of these apart and on every one the guides were cracked.
If you decide to do this yourself, it's not that hard, give me a PM. Your local and I have the timing kit.

 

Well done, and a sigh of relief for both of you....

 

Well caught...

 

I had just my uppers done at about 88k on my 97 XK8 convertible. Has about 100k on it now and no problems about 4 years later. I was thinking of upgrading to an XKR at the time and now pretty sure I’m not actually going to do that so I am actually regretting not doing all of them at once but I’m definitely not having any problems so far. Also no difference in how the engine runs. Both of my old tensioners had body cracks developing and one had a shoe about to come loose/off but they were still working. They can self-destruct either from use or from age, so mileage is not a very reliable yardstick at this age...

 

I bought this car from a guy that waited a little too long.
He started it one morning and started running rough. I assume it just jumped one tooth. He took it to an unnamed shop to have it diagnosed. They ran the engine trying to diagnose the problem, this shop didn't specialize in Jaguars. The engine eventually froze on them.
I bought it for $800. Before the shop worked on it it was probably worth 6 to 8,000.
This is what I found when I took the cam covers off.

And what I found when I took the head off


This was 4 or 5 years ago. The car is back on the road now.

Moral of the story is definitely change the secondaries, unless you have a coule of spare engines like I do. If you only do secondaries look down at the guides to check their condition. If you can afford it and plan on keeping the car change the guides and primary tensioners too.