There's no secret that the timing chain tensioners on the 5L V8 2010-2012 engine were prone to premature failure and as a result, Jaguar/Land Rover "redesigned and improved" the guides and tensioners. When replacing and installing new tensioners, there is a discrepancy in the Land Rover technical manual vs that of the Jaguar manual. The LR manual indicates that one needs to pre-load the tensioners, whereas the Jaguar manual indicated if the tensioner are new, pre-loading is not necessary. Another discrepancy follows pulling the grenade pin. LR state no mechanical force should be applied, whereas Jaguar and others on this forum have indicated "considerable force needs to applied again the guide" to allow the tensioner piston to extend as far as possible. Jaguar also describe in the manual that if the guide can be pushed back, the tensioner hasn't been installed correctly. I have tried both methods (LR & Jaguar), and am not sure if these tensioners are operating as they should. In this video, you can see the tensioners flexing back. Is that normal? Does one need to pre-load the tensioners new out of the box? If so, anyone have a video of them actually doing it?
Here is a video:

 

That is 100% not correct.

You have missed the final step of levering the timing guide blade against the chain until it "clicks" - this hits a ratchet stop on the tensioner so you can't push it back in - see Step 18 of the attached Workshop Manual section.

You mention "considerable force" - Jag are not f**king around here - I had to use a long 1/2" drive extension bar and a LOT of force to get it to click. The click wasn't as audible as the manual might make out, but you'll know you've got it right because you won't be able to push it back in again.

 

This may also help - you can ensure the tensioner is set correctly by removing it and resetting it, then holding it until installed using a small allen key

 

Having davetibbs say you forgot to do something has gotta really hurt...
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Current Hers: '13 Lexus ES350
Current Mine: '15 XF (X250) Portfolio AWD
Jaguar - making mechanics out of customers since 1935

 

Thanks for your response. I ordered new tensioners and will apply major force, though I've already done that to no avail. So part of the issue I am having is with resetting the tensioners once the pin has been pulled. Dispite watching the video several times, I have not been able to successfully reset them. Regardless, step 13 states "If a new timing chain tesnioner is installed do not deploy the pin and proceed to next step." I assume the tensioners purchased from Atlantic British, are pre-loaded and ready to go out of the box. I am not clear as to how much flexibility the tensioner should have as illustrated in step 19 once the first stage ratchet mechanism has been applied. Should there be absolutely no movement at all?

 

It beats having to go into this engine a fourth time

 

Since your now an expert, can you share any details on removing the crankshaft nut (the one with the crazy high torque)? Most of this job seems OK but that bolt has me worried, even with the correct tools. How did you find the task - easy, nightmare, etc. Also, any chance you take some pictures or video (even better) when you re-install. I'd like to know what I'm in for when I eventually have to do this. And good luck with getting this sorted.

 

Dave, stupid question. How are the tensioners "reset"? Other types of tensioners I've worked on have a similar spring loaded piston and ratchet mechanism but they also had a way of releasing the ratchet so the piston could be pushed back in. On these Jaguar tensioners, once the piston starts to extend and the ratchet engages, how can it be pushed back in?

Thanks in advance.

 

Atlantic British has a youtube video on how to remove the crankshaft nut and related parts to get to the timing chains. You will need to identify what bolt you have to determine direction of thread. Mine was reverse thread and had relatively no problem removing it using a high power impact gun. Removing the crankshaft pulley itself, I used the following technique: Lastly, since my engine had seized, I rigged up this plate with a lever to turn it over with much force. This likely will not be necessary in your application.

 

Yes - the tensioners should arrive with a pin with a ring attached installed in them, preloaded. This is what I did:

1) Install guides
2) Install chain
3) Install tensioner
4) Push guide against chain with hand, pull pin
5) Lever guide hard against chain, getting enough movement that the tensioner hits the ratchet stop.

You'll know you've got to this point as you won't be able to push the guide and compress the tensioner pin into the tensioner body.

Basically none. Certainly not any kind of perceptible movement. You should not be able to push the tensioner back by pushing on the guide/chain at all.

To reiterate: I'm not the strongest guy out there but I was really surprised at how much force was required against the back of the guide to get the tensioner to ratchet. Think crowbars.

 

Thanks Dave, I’ll be receiving the replacement tensioners this week and will record the process of installing as you have outlined. At this stage I’m willing to apply enough force no matter what.
According to Atlantic British the tensioners are pre-loaded.

 

Well, here is the verdict. I installed the tensioners according to the Jaguar manual to apply "considerable force" against the guides to ensure tensioners have hit the ratchet stop. There was no movement in either guides and the chains were taut. The chain on Bank 2 was super tight as that tensioner was extended nearly an inch. Truck started up and ran fine for 2 miles before breaking down and not being able to start. Took front end apart and found timing skipped on bank 2 due to the intake camshaft bearings failing. I suspect I had applied too much force against the guides (using a ½-breaker bar for leverage) and the excess pressure on the camshaft restricted lubrication of the bearings, causing it to bind and eventually seize. Needless to say, the cylinder head on bank 2 is toast.
So now I have to do a head gasket and timing job again. What aggravates me is not so much the cost and time it takes to do this job, rather the uncertainty of how to install those damn tensioners correctly. "Considerable force" is too vague of a description on installing such a critical part. Some say use a crowbar, some say use your palm, and some say don't use either. I have tried all three. Some say to apply force until you hear the second click on the ratcheting mechanism of the tensioner. That click is not always heard. I’ve tried it on 8 (yes, eight) tensioners and could hear a pin fall in the shop but no second click. The click I hear is from the tensioner cylinder hitting the guide after pulling the pin, and the second click would be from the tensioner cylinder locking into the grove of the guide

 

What a complete flipping nightmare! A horrible job just became a soul and wallet crushing job. Dealing with a bad head may now make the job to repair it cost more than you just just buying another XF and selling this one for parts.

Both of my XF's are gone before having to deal with those chains, thank goodness!

p.s. "Truck started up and ran fine for 2 miles..." You on the wrong forum??

 

Yes, it is a nightmare but I'm not giving up on it. I have a replacement head in place now. Though my vehicle is a Land Rover LR4, it has the exact same engine as the XF hence I am addressing this forum on this subject.

 

Ah, I missed that you had a RR SUV.

How did you come across a head? Hopefully it's isn't a warped one from an overheated engine since there's a ton of overheated JLR V8's floating around after their plastic coolant pipes let go (the other huge weak point of these cars).

 

Assuming my logic isn’t too faulty, the tensioner should be able to accept being one ratchet stop too loose.

The whole point of the tensioner is to adapt as the timing chain stretches over time, maintaining tension. At some point your chain will stretch and the tensioner will be a little loose, extending maximally 0.99 stops from its previous ratchet position. That’s okay, that’s why the ratchet intervals are spaced as they are. Eventually hydraulic pressure will push the tensioner to click into the next position.

The ratchet stop is there to prevent the tensioner from being too loose when the car is off and the hydraulic pressure is relieved. It is not there to apply hundreds of pounds of force to the chain. I think the suggestion to apply considerable force is to mimic the force that would be applied by the hydraulic mechanism (something more moderate) to make sure you aren’t very close to the next click position. The internal tensioner spring doesn’t push hard enough to verify you are within one ratchet position of optimal tension when you are first setting up the new tensioner.

Even if you did it wrong and didn’t push quite hard enough, the hydraulic pressure should eventually push the tensioner into the correct position.

Again these comments are merely based off the logic of design, not my personal expertise.

Best of luck.

 

I found a good used head on ebay, cleaned it up good and had it checked for any warping at my local machine shop.

 

Nedoerr, I believe in the logic behind your description of how the tensioners are to operate. They are hydraulic and primarily dependent on oil pressure.
After installing the replacement head past weekend (had to do that job twice as the heat shield got wedged between the head and block and didn't realize until filling with coolant), I noticed my oil filter was dry. There is little to no oil pressure in this engine. I am amazed that engine hasn't seized. The culprit is either a faulty oil pump, or a clogged oil intake pipe. I sincerely hope it's the later as I'm not looking forward to pulling the engine again.

 

Wow the nightmare gets worse!

Did you use a new head gasket after pulling out the heat shield? They are single use aren’t they?

Your engine may not have seized, but you could have bearing damage that will cause an engine failure soon from that oil starvation.

 

Ouch. Assume your oil level is okay?