I really know that this topic has been beaten to death on here, but I cannot seem to get any straight 100% credible answer:

Were the third generation metal timing chain tensioners factory installed on any X308 cars? If so, from which date/VIN? If not, at least I'll know!

Thank you.

All AJ27 ENGINES assembled after August 13, 2001 contained the metal tensioners. While there may have been a short pipeline interval between engine assembly and vehicle assembly anything after August '01 most likely had the later tensioners.

If you fall into that narrow window of late August based on the vehicle assembly date found on the driver 'B' Column it would be best to ask your friendly local Jaguar dealer to produce your build sheet based on the VIN. The engine assembly date is encoded into the engine serial number (yymmddhhmm).

Straight enough?

And jaguar considers this a maintenance wearable item, total bs.



There should never be plastic or nylon inside an engine.

On Fords, the timing chain tensioner guides would strip of the nylon plastic, pieces would get inside the engine, cause rod knock and engine failure from clogging up the oil pump as well.

But in small claims court, that would not fly.

The above referenced date is correct,.......however. My cat is down (see my post) due to the loose chain on the second generation tensioner. When I bought the car, the seller claimed that "all important updates" were performed, and produced the receipt that showed the replacement of the tensioners. She ran beautifully (without ANY rattle), and I was too confident (and maybe lazy) to open her up and check.

The ONLY way to know for sure, is to open her up and check. When one is changing the spark plugs, half the work is already done. Few more bolts, and the cam cover comes off. Visual inspection is the ONLY sure thing.

Many people were in the situation I am in today. I know better, than letting this happen. Feel like standing in front of the mirror, and slaping myself multiple times!

OPEN IT UP! Look, and replace if necessary. All you need is 7mm and 10mm sockets. Takes about 10 minutes to unbolt the cam cover.

Many of the early cars had the tensioners replaced with the external spring assisted plastic tensioners between their introduction sometime in '99 and the metal ones in '01. The plastic bodies and chain slippers just as reliably fail but the spring tension masks the chain rattle often reported as a warning. Therefore, I consider the spring assisted ones even more dangerous that the first generation.

The spring assisted 2nd generation ones were sold from stock and places like eBay as recently as a couple years ago so the fact that a car's tensioners were replaced within the last few years is no guarantee that it was with metal.

i agree totally you need to take cam cover off....and see for yourself......the use of plastic tensioners is not just a "jaguar"oversight....many cars from the same period used plastic....hard to believe you wonder just how much....money are they saving with this practice?nor does it sound like an elegant engineering solution for keeping things together.
I can take it a step further as this very problem....hit me on my maxi-scooter....and no metal replacements available (need two).....the difference being if your off on the sprocket even one link....the ecu shuts down the scooter............preventing further damage.....with the jag...maybe not so lucky.

The date given is NOT the automobile build date, but rather, the engine build date. The engine seriel number decodes to the build date and time.

Since we are both in SoCal mountains, I'll give you a neighborly advice.
Go on Ebay, and look for Christopher's Foreign Autoparts. They have a complete kit (which I purchased about 20 min ago for $299), and they also have a video showing how to do it. The kit includes valve cover gaskets, metal tensioners with bolts, and two secondary chains that have master links in them. The stuff can be purchased cheaper in pieces elsewhere, but one has to drive, and spend time looking for it. To me,.....three bills are well worth it, and I don't have spend any time on the phone, or in traffic.

Heck, since we are neighbors, you could drive to my ranch, and we can do them both at the same time!

In that particular circumstance where you relied on a positive statement by the seller to your detriment, you would have legal recourse. If you wanted to bother and could prove that the receipt was shown to you.

Just a thought.

I still have the receipt. AND I am an attorney by profession. However,......at the time of the purchase I did not know that there are three generations of tensioners in these cars! I've heard (from my mechanic) that in order for these cars to be worry free (like ANY machinery ever is!), certain things need to be done. One of them was "secondary timing chain tensioner upgrade". They were upgraded. From the original plastic ones, to the plastic ones with an external spring. They are not metal. Seller didn't mispresent anything. I doubt HE knew what generation tensioners were installed. The receipt simply says "timing chain tensioners replaced". Nothing else,...... and NO recourse.

I was telling the OP, not to relay on the paperwork (no matter how descriptive it might be), but to open the covers and look. And I should've done the same a year ago. Looks like I got lucky, and the whole fiasco will cost me only 300 (it would cost the same if I performed the upgrade before the failure) which I consider the "dinner money". But I learned!

Since I plan to buy the Range Rover, I think I should join the forum BEFORE I buy it, and learn as much as I can. I fall in love (cars, women, whatever), and THEN I do my "research"! A$$backwards.

I installed MANY MANY second GEN tensioners. We were issued TSB 303-30 and the spring added seemed to be the answer to 'RATTLE AT STARTUP'.

Yes the second Gen tensioners fail the same way the first Gen ones fail.

It was early in the 4.0 evolution.

bob gauff

I can't refer to any particular thread, but I recall seeing some posts in the past couple of years warning that chains with master links failed.

Totally agreed. It IS the engine code you need. And yes the magic date is August 13, 2001 at midnight. Thus engine code: 0108130000.


Last four digits represents the time of day in military time as indicated above. Thus 0000 = Midnight.

There are more than a few documented cases where the car build date (on the door column) is September 2001 BUT with an engine that was manufactured before the cut off date. I know, I got one.

A Jaguar dealer will usually give you the engine build date (engine code/number) over the phone if you give them your VIN. But you also need to be aware that some of the engines in these Jaguars have been switched out. So there can be a case of a failed engine (for any reason) that has an engine that may be months, if not years, older than the vehicle production date.

My comment on chains was perhaps too negative. I owned and worked on Alfas back in the 60's. They had chains with master links and a slip on keeper, just like bicycle chains, and I never heard of a failure. So, it's not like you can't make a good chain with a master link

LOL....don't we all!

I'm sorry I know this has been beat to DEATH (isnt there a gif for that somewhere??) but there's a deal that just popped up in Socal on a XJ8. He's had the tranny rebuild but as the second owner wasnt sure about the tensioner. I found this:

In their Technical Service Bulletin No. X303-68 of February 2005, titled “Rattle From Engine on Start-up and Idle,” Jaguar states:

This Technical Bulletin has been issued to address customer concerns of a rattle emanating from the engine on start-up and idle.

Cause: Failure of a primary or secondary timing chain tensioner.

Should a customer express concern, and the fault has been confirmed as a timing chain tensioner, new primary or secondary timing chain tensioners must be installed.

Engines subject to this problem include XJ8/XJR engines with the last six digits of their VIN numbers between 812256-F41862, and XK8/XKR engines with the last six digits of their VIN numbers between 001001-A24195.

Ok that being said is there any way to know for sure if the tensioner has been replaced? Carfax? Dealer history? Or just crack it up and check?

Thanks guys. This n00b owes y'all drinks for sure!

Welcome to the forum!

The ONLY way to be sure is to remove BOTH valve covers. There has been more than one post on finding only one tensioner replaced.