Chain tensioners

[dougallen]

I have a 91k 2001 XJ8 with i believe 2nd generation tensioners. Water pump and thermostat just replaced and engine check by main dealer who say car is running beautifully. No noise on start up. My question is whether the tensioners will see me through a year or two as I run it only around 5k each year with regular servicing - or am i worrying needlessly Apply Ametech engine retore annually which improved engine performance

[J44EAG]

My reply is in blunt form.

It is not a question of if the tensioners will fail, it is when.....

Here are mine at 44k miles. The example on the right is from another car. Bottom foot recovered from the sump. Note the cracks on centre and left examples.

You will find many postings on the 308, XK8 and S-type BBs relating to this subject. Replacement ali units are around £90 a pair. Labour of course at extra cost.

The only reliable units are the fourth generation items which appear bullet proof. Note how robust the ali unit is compared to the previous plastic versions.

Mike

[ptjs1]

Doug,

If you use the "Search" function and look for "tensioners" just on the x308 section of the BB, you'll find 140 posts on this subject!

Even a quick perusal through the various threads will indicate some differing views but a general consensus of opinion that 1st & 2nd generation tensioners will all eventually let go and often without any warning.

Spend a pleasant evening reading the various posts, then sleep on it. (Of course, you won't get any sleep as you'll worry that they might be failing even whilst the car is sitting on the driveway!)

Good luck with whatever you decide.

Paul

[malclamour]

Have just traded in my XJ6 300 for a 1998 V8 Sovereign with 78000 on the clock, and after reading about tensioners have started worrying. Is this peculiar to the V8 ?....What other horrors are in store ?.....I am 85 and just travel to the Supermarket, with an occasional visit to the countryside pubs for a meal.....Annual mileage around 3000. The car is an absolute pleasure to drive.......Malclamour

[J44EAG]

I`d strongly suggest you have a competent Jaguar man examine your car and ensure that the ali tensioners as shown in the above images have been fitted. The brown plastic tensioners shown above were from my V8 S-type at only 44,000 miles. The cracks are clearly visible and would have failed had I left the units in place.

This problem is no respector of low mileage or even gentle driving. If plastic tensioners are found, they will need to be replaced. That done, the engine will achieve a high mileage.

Mike

[robv12]

I have to agree, get these tensioners checked if there is no evidence of them being changed, look for an old invoice in any history that came with the car to see what you can find

Lifting the cam covers to check is easy, about 30 minutes a side, lift the left hand one first, as a very well known specialist told me that for some reason this is the one that fails first most often, this has been proven every time I have done this job. if the you see plastic tensioners, either complete or in pieces, buy the ally ones and have them fitted, you will need to hire an engine locking kit from the JEC tools and spares

http://www.jec.org.uk/shop/69/engine-tools.html

I suggest the tensioner kit from this guy, this is the complete upper and lower kit, you will only need the top tensioners and chains

http://www.ebay.co.uk/itm/JAGUAR-V8-TIM ... 439c7736ba

allow 3 hours to do the job, a bit more if it is your first time

hope this helps, ask if you need more advice