First post here. I bought a 2006 x300 last fall with 110,000 miles. I’m planning a first extended trip from Minnesota to San Francisco. The car is performing just fine and no unusual noise from the engine, but many posts cautioning about chain tensioner has me wondering about determining the condition BEFORE it causes a problem. Any thoughts would be much appreciated. (I’ll look thru the existing postings too.
Well 65,000 to 100,000 and thats pushing it to the edge.If your chains go the motor blows up, bent valves and crashing gears , its fatal.
Get it done YESTERDAY. Add in fuel pumps and filters and you should be fine.
gtjoey1314
Guy I bought from had some, though not all earlier maintenance records. Maybe more importantly, has a previous owner name and dealer who serviced the car. Fingers crossed, I can get verification the chains were done when they were supposed to be. Thanks much for your comment. I appreciate it.
Anytime Enjoy the ride!
2006 should have the latest upgraded tensioners unless you are hearing any undue noises I would just drive it.
Robin I agree, 110,000 miles is still alot of miles for any mechanical parts.
Im not saying its bad but still miles.
Robin and j, Thanks for both comments. The car runs very smoothly, quiet and no engine noises of concern. I’m looking at the manual and service recommendations and see nothing about timing chain or tensioner concerns. Drive belt wear, yes; but nothing about chain/tensioner. So, just trying to decide whether a longer trip is problematic or not. I realize there are never guarantees, but seems if chain or tensioner were true wear items, Jaguar would recommend replacement ?
X300 2006 don’t match up.
Where is the typo?
Sorry Andy, it’s an XJ8 Kevin
Hi Kevin, I have the earlier incarnation in a 1999 XJR 4.0 S/c
The car had the 1st gen tensioners replaced just prior to my purchasing it a few years ago, since then I have done classic trials on a few race tracks around the North Island of NZ, participated in a few Targa Tours as an official car, one involving driving to the bottom of the South Island from Auckland, then doing the tour and driving back home, another trip to the same location for our National Jaguar Rally.
All of these trips were accomplished with just normal oil changes. The only mechanical was a real hub bearing failed on the way home from the SI Targa which lead to some interesting handling on the corners.
The Targa tours I was in was limited to 130klm top speed for safety reasons but you were still flinging the cars around the corners in a spirited fashion, impressed a few Porsche drivers 
Just my 2c worth.
Regards Robin
if chain or tensioner were true wear items, Jaguar would recommend replacement ?
Not really. Those documents probably don’t mention that the thermostat housing is prone to cracking or that the water pump impellors like to break up. They may also not be aware of the effect that high sulphur-content fuel would have on the Nikasil engine liners. Nor…you get the idea: these are things that have been noted over time and with experience.