So as mentioned my 2000 S Type is at the mechanics getting a full tensioner kit install with 4 new metal tensioners, new idlers, guides and chain along with some other unrelated work (ball joints, new shift linkage, heater valve, exhaust manifold).

Anyway my mechanic just called me to say that despite almost no rattle when we took it in (I decided to do as a matter of maintenance) that when he took the timing chain cover off, one of the tensioners was already cracked in two and just resting in place by sheer luck not causing any major damage. In fact of the four, 3 (both uppers one lower) show significant fatique or failure!

Mechanic did say that the car internals look very good and that he can tell the car was not mistreated, no gasket leaks, no worn or scared metal and no hint of overheating. He said that is probably the ONLY reason those tensioners lasted 119k. He says he cannot recall replacing many sets over 100k that had not broken causing damage.

Is he accurate that 119k is an extreme upper end for original 2000 tensioners to last?

When have others had them changed and what condition were they?

I am counting my lucky stars today, seems I dodged a bullet and have a decent Jaguar moving forward (crosses fingers).

 

Wow, lucky you! You didn't dodge a bullet you dodged a heat seeking missile!

 

Yes. You were running on borrowed time!

Exact mileage to failure is always uncertain. It really does not matter much if the car has been maintained or not because the failure is a design problem.

DOHC engines have a very unique and rough load pattern on the timing chains as the valves open and close in odd patterns. So you get wild harmonics going on. It just pounds the tensioners to pieces and even Jaguar took three tries on the tensioners before they got them to last. Then they did a complete redesign for the 2003 and up cars that included a double chain for added strength and life on top of the improved tensioners.

But you did not have anything let go so no harm and no foul!

After replacement you should not need to touch them again for the life of the car.
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That is good to hear. I know these cars are not instant classics and the 1500 hundred or so I am going to put into it I will never get back, but then again I am not looking to sell it

I'd like to believe (and hope!) that I have now done everything I can to take this Jag to 200k which given my stable of rides and the fact that this baby will be a pampered garage queen probably means the rest of my life!

Also just learned that previous owner had replaced the exhaust with a Catco all stainless steel cat system. Mechanic says its looks almost brand new but putting it on improperly is what probably broke my manifold in the first place.

Not sure if a new Catco system is something I should be happy about or not! lol

 

Update:

Got the car back, runs amazing. Went ahead and had the control arms replaced so my total bill for the 4 cam tensioner replacement, new timing chain, new guides and idlers, new control arms/ball joints up front, new heater valve (my part) and shift linkage adjustment came to $1,789.00

Not cheap, but it was fix it or trash it and the car is beautiful and in great shape.

One question lingers. I was certain I had a cracked driver side manifold, but mechanic said upon inspection that there is no leak in gasket or crack and that the "fluttering" sound on heavy throttle is not from the engine. He suspects it is the all new (and not stock) exhaust and catco cat system on the car.

Does this sound right? The noise - to me at least - sounds exactly like an exhaust leak, but mechanic says no... i am puzzled.

Any feedback appreciated.

 

I've got the same ticking going on only mine is at idle aswell. It sounds very much like an exhaust leak. An added problem to my situation is it smells like fuel in the cabin. Maybe the charcoal cannisters rubber hose has dry rotted? Or possibly the purge control valve?

 

I took my car to a very reputable jaguar mechanic today who was recommended by someone on this forum. I asked the guy to just check to see if I had the orange tensioners because I hadn't had time to. He said that would require them to pull the engine out and it would take about 8 hours just to see if I had the old ones or not. Now I know this isn't true and I was surprised as there were plenty of other S-types and Jaguars in the shop so I know he's worked on them a lot.

 

It actually will require something approximating 8 hours to pull both the upper and lower tensioners because the engine must be lift up partially out of the bay.

However just checking the uppers - which should only take a few hours - would tell you if you have the plastics (while turned orange to heat) or metal.

 

It is true that checking the lower tensioners is not easy. But you can check the top ones with little time or effort.

Just remove the cam covers. The secondary tensioners are visible with them off. Now it is possible that just because the upper tensioners are still plastic it does not mean the lower ones have not been upgraded. But the odds of someone doing the lowers only is very small. Once you tear the front of the engine down far enough to get to the secondary ones you would be a fool NOT to change the uppers (or secondary) tensions too.

Here is an old style plastic tensioner from a 3.9L Lincoln LS engine.



It does not require the engine to be removed to do this repair. It would make it easier but everyone I have seen has been done in car. You just need to take the entire front end of the engine apart.

Here are the updated metal ones. They still have plastic where it touches the chain but the rest of it is now metal.


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