With all these cars out there loosing tensioners and causing 3k dollar repairs to blown motors I think Jag should have done something about this issue. I am sure they knew early on that the plastic tensioner was a f'up. They should have did some good will and fixed these and recall the damn things. Because as the years pass and these cars sit out there and folks learn of this little dirty secret this is going to be the modern version of the electrical issues of the 80 through early 90's models.
I say SHAME ON JAG!

 

It's the same ball they dropped for the hydraulic hose system for the convertible top!


Doug

 

I don't know if it is the same drop of the ball. A BLOWN MOTOR vrs a hose issue. The cose to repair is pretty diff.

 

Not really... it's more the exact opposite. They found out the tensioner had problems... they replaced it with a newer version, still plastic... then that had issues so they finally made them out of metal. Later XK's have this issue corrected.

With the hydraulic hose, they got it right the first time. 97-98 models don't fail, or failure is very rare. After 98 they changed hoses twice, with the second model still failing. So they went good to bad.

 

Believe me when I say Jaguar engineers know the Ford accountants were in charge. Their little plastic mistakes (Tensioner, water pump and thermostat housing) cost them $ millions and $ millions in new engines in warranty claims. And, their reputation for problems cost them thousands and thousands of new car sales.

It took'em from 1988 until 2005 to get their parts re-engineered. Now, Jaguar/Tata is at the top of R.L. Polk's list fewest inital problems--with Lexus and Honda.

Their problems cost Ford $ billions to bail out of Jaguar. What a screwup.

I put 1 million+ road miles on Ford vehicles, before my retirement, without a single ABS light. I just don't understand why someone cannot come up with a Jaguar electronic box/ABS motor that actually works.

 

why o why do we love thes deedfull cars, With the sme issuse we would ridecule any other make, Just like we are with women we let the little head rule the big head.

 

And didn't Ford actually improve reliability considerably from before the purchase?

I've heard from quite a few people earlier Jags were even more unreliable...

 

What could Jag do that would be pragmatic, not bankrupt them, and return some semblence of confidence? It's easy to talk about, but what is a real world fix?

 

I need to re-research this issue. My mothers 96 shows no record of the tensioners ever being touched, now with almost 170k on the odo.

Same for the water pump.

Dumb luck? Probably, but I would like to see this car reach 200k+

I recommended updating the chain tensioner when she purchased the car (from the original owner) with 60k on the odo.

 

What is the problem!
You know about the existence so if you are worried just change them out for the rev 3 ones and the problem is solved.

The XK8/R is a pretty reliable car and considering the only thing which fails on these engines is the tensioner which can be changed upfront if you missed the telltails.

 

This why I was able to buy a $74,000 cream puff for $8400 and with the help of this group fix all the problems before they did any harm.

Behind every dark cloud is a silver lining.

Charlie Pace

 

Let's see. I'm an auto manufacturer who needs to come with a relatively cheap small part whose sole purpose is to keep tension on a timing chain. Failure of that small cheap part results in significant damage to the engine, and inspection of and replacement of that small cheap part is difficult. Oh yeah, the small cheap part is operating under conditions of high heat and vibration. Bingo--let's make the part out of plastic (RIGHT!!!)

The lack of forethought that went into making something like this out of brittle plastic versus a more robust material goes beyond boneheaded. Similar thought breakdown for supplying a hydraulic hose that must see pressures of 1000psi+ and is also subject to heat and vibration and is extremely difficult to replace.

Oh yeah--these parts are not going into some cheapo econobox. They are going into a high end car that sold in the $70,000+ range when new.


Doug

 

differant engine, not the same issue. Although your monms does have a tensioner that bled down oil pressure and causes chain buss on startup. Mine has done it for years even though i installed the newer updated tensioner for 6's. But with time it becomes an issue with the oil pump chain slack too.
Also other than a plastic bodied tensioner, you need a plstic slipper and blades to give a sacrificial and quiet surface for a metal chains to slide over. Just like nikasil, porche has used this for years without issue, so why wouldnt jaguar think they could do the same??? Get out in the real world and not on a engineers pc and differant stuff comes into play. What would you rather them do, build a engine with timing belts instead of chains that have to be changed every 60k???
V8's from many manufacturers having been using plastic for decades to provide quiet engine operation. Think about plastic coated gear teeth for timing chains. Those go away and chain jumps time and bends valves too and costs engine repairs/replacements. Chevy ford, and chrylers have had these type issues for decades. Timing belts jump or break like on my ex's car and took out the engine on her car too and it was due for the 2nd belt at 120k, 1st done at 60k, so its not supposed to break right at 60k!!!!!
An irresponsible manufacturer would not change or redesign a known issue for a known problem, they did. Same on hoses doug. We had issues on all xk's with top hoses, even though they tried to produce a retrofit kit to reduce customer costs/and theirs for the short time that the splices were found to not work either. So in light of this they produced a much better convertible top system for o7's and up that we have very very few problems with. Problem fixed with a redesigned new car. Same on the air suspension of the xj's. But as many know, many times you fix 1 issue only to creat a differant 1

 

In the early 70's when I hired in at International Harvester Company, one of my friends, a design engineer was told by his supervisor to design parts to wear out. In those days, without much competition, the big money maker for these companies was the sale of parts, they made all of their own. I believe that philosophy has changed in the corporate world, and many of the auto manufacturers were forced by foreign competition to create a quality product. And Brutal's right about the plastic coated gear teeth on American engines, My 1967 Chevy 3/4 ton had a 283 with the plastic coated timing chain gear. Overhauled the motor at 275,000 miles. So these plastic parts have held up under these conditions.

 

The plastic tensioner does not look any cheaper to produce than the metal tensioner. In fact, it looks to be a better design that would have been bulletproof in metal. The problem in the plastic tensioner is the stresses from the keyway between the plastic body and the metal piston barrel. That is apparent from the way all failed tensioners showing the same crack in the same area.

One of the stories behind the cam drive on the V8 was the desire for a short engine. It resulted in using a single chain instead of a double chain so that the precious inches could be shaved down.

Another factor was the push to reduce weight. One ounce at a time.

And finally, there are pictures on the web in articles discussing the newest oils which show chain guides on other cars in the same type of material which show the same type of wear as the plastic tensioners on the Jaguar V8. These would be the low viscosity, fuel economy rated oils that the manufacturers relied on because of EPA mandated CAFE ratings. That is a separate matter from the reduction in ZDDP targetted at the EPA mandated catalytic converter warranty.

 

^^^ also the plastic slippers are thicker with more wrap around the metal pad its bonded to. There are really more slippers that come off the full tensioner failures. they can be just as damaging since if they gets crunch between the chain and sprocket it will either snap the chain or streach it. this always leads to chain breakage down the road

 

^^^

Yes, the slipper on the plastic tensioners are a lot nicer than on the metal tensioners. Waiting for someone to try putting the two parts together as sometimes the piston and slipper come out in almost mint condition even after the body has cracked.

The metal tensioners also have a lighter spring that suggests less ability to control chain whip at initial cranking.

 

no i was reffering to the metal tensioners plastic slipper being better

 

Sorry, I don't know what I was smoking - it's a 97

 

The failure I see is that Jaguar has failed its most valuable asset and that is its customers! A failure that will be a long and hard road to recover from!