Tensioner bafflement

Hi, I just acquired a 1998 XJR, complete but not running. I love working on cars but haven’t had the chance for the last few years so I bought this as a (hopefully fun) project. The body is sound and straight with no rust anywhere. The exhaust system looks great. Paint is British Racing Green and looks okay. After some compounding and a little touch up, it should look very sharp. Upgraded front brakes (Brembo with 15 inch discs). The interior color is oatmeal. Passenger and back seats look great. Driver’s seat left bolster is split although the rest of it looks serviceable. Mileage is 200k. It gives the impression of a car that was well-kept (at least until recently, as it has three different brand of tires on, none looking too great).

I started my project after seeing no fuel pressure. Both fuel pumps were dead, and the fuel filter was completely clogged. I wonder if the latter caused the former. After fuel pump pressure was restored, it still wouldn’t start. I took out the coils and plugs. Plugs are fine, NGK platinum. I really don’t know how to test the coils. Since I was already into the engine, I decided to take off the cam covers, having read about the secondary tensioner failures. Here’s my bafflement: the tensioners are the original orange plastic ones. From what I’ve read about them, it seems an impossibility that these tensioners could still be intact at 200,000 miles.

Is it possible there’s been an engine swap? Or is this just a freak occurence?

Explanations, theories and wild guesses are welcome.

Hi Royce,
I also have a 1998 XJR and have owned it since 2008. Been dealer serviced, relentlessly, since new, but by myself since 2008!

In 2009, based on X308 folklore(aka common sense) at 180,000+ km I decided to change the secondary tensioners for the latest metal variety. This is a reletively simple job compared to changing the primary tensioners as well.

Anyway, when I got the original secondaries out they still looked good, fresh but did have some very small cracks in the plastic(phenolic) but not at all close to the point of affecting or impeding the piston action required to tension the timing chains. But… I’m glad I did it!

Another so called “must do” is to change the transmission fluid and filter…this is a “sealed for life” system. I had this performed in my car by a specialist at 190,000+ km. The filter was perfectly clear of swart(metal particles) and the old fluid looked ok(not burned etc) and the the transmission internals looks clean and new.

Talking to many knowledgeable Jaguar mechanics and owners it would appear that in these performance cars it is important to observe the very routine, banal and frequent maintenance schedule. It cannot be overlooked or overstressed how important it is! For instance frequent oil and filter changes using the correct grade and quality oil and filter, coolant system etc. Do all the coolant fans run when they should? An X308(XJR) gets VERY HOT after just a few 10’s of seconds when driven hard if only one of the two fans doesn’t run or the coolant is low or rad is leaking or blocked or the water pump is on it last legs etc…

I still own the XJR and so far at 235,000km…no issues at all since I bought it, no rattling, no cooling issues, no transmission issues, no codes, no electronic issues, no limp home messages. I have regularly greased all the nipples in the drive system, changed the front suspension bushes and ball joints as a precaution, a couple of rear brake lines, front brake disks and pads all round, O2 sensors with Denso’s…soldered the dry joint in the ABS computer(cost more and took longer to bleed the brakes after!).

Pamper it from new or confirm that it has been and it should be fine with normal regular maintenance. If it hasn’t been…start replacing critical stuff and start pampering…it is worth it…these are fine nealy 400hp saloon cars with blistering performance that are actually well engineered

Kind regards,

Chris R. Gates

Tel. :- (+47) 915 62627

Apparently good oil changes can keep the plastic ok.

It’s possible plastic has been swapped with plastic.

Leave a spark plug out and see if you get a spark.
Do a compression test. If bad put a tiny bit of oil down the bores