Hello guys, and maybe gals,

I just bought a 2001 Jaguar XJR with 83000m - I have noticed that there is a ticking noise upon cold starts then after 3 or 4 minutes the noise goes away and the car runs like a dream. I have read some dreaded stories about tensioners and I was just wondering if the tensioners were on their way out would the noise be constant and not just limited to cold starts?

I also have a nocking sound coming from the back of the car - very annoying indeed. I've had the spare wheel out, checked the silencer mountings and they seem to be fine. Any ideas??

 

Mine was the rear stabilizer bushings.

 

It sounds to me like you have a case of "engine morning sickness", I think the engine noise you are hearing is from your lifters. When engines get some miles on them they often get this. What kind of oil are you using? Is it what is called for in the owners manual? Is it a full Synthetic? You may want to start changing the oil and filter a little more often to try and clean up the inside of your engine.

There is a product made by Chevron, I think it is called something like Techron that you put in your gas, this works great at cleaning the buildup of residue from the valve stems, and combustion areas. I'm not sure but I think it also cleans injectors. I have used it in the past and it works great! Clean injectors, a clean throttle body, a clean PVC system, a smooth running engine will help keep the engine insides cleaner, and oil clean longer.

Check and make sure the engine is running at the right temperature, too cold is just as bad as too warm. Too cold and it is more apt to gunk up the engine insides. Too hot, when the engine is shut off, the oil is more likely to drain down from the lifters etc where you would like it to stay. Have you checked the outside of the radiator, it may be full of bug residue. You can check the temp with a hand held infrared thermometer.

After an oil change, and when it is running well, you may want to take it out on the open road and blow the cobwebs out of it. After all it is a Jaguar, and baby they were born to run!

 

PCV

 

The PVC of our X308 can never cause a knock, supercharged or not. All we have is a breather tube that goes directly into the intake, no diaphragms, coolers or valves. Whatever X300/X308 engine. Also, none of the X308s have hydrolic lifters. Only buckets.

Knocking/ticking in our ENGINE can only have 4* main causes:

Non VVT / Supercharged V8:
1. Exhaust leak (ticking)
2. Valve to valve bucket clearance (ticking)
3. Tensioners waiting for oil pressure (more ticking than knocking)
4. Bottom end (keeps ticking/knocking, even when warm; knocking), rod knock $$$

VVT (so 5 causes):
5. VVT actuators/solenoids (ticking)

Ticking noise can also be caused by a cheap/old belt. I've experienced this myself on my old XJ 3.2. A hard tick slightly faster than every second that stops after about 10-15 seconds. This is the tensioner that snaps back because the belt has a kind of "memory" position where the rubber remains in a bend shape for a short time. This causes the tensioner to keep snapping back and making a noise. This often happens at colder temperatures.

My XJR "ticking" noise only happened on cold startup. It sounded very worrying, On accelaration a ticking noise on the left bank could be heard at all times. My issue was nr. 2; valve to valve bucket clearance (ticking) on a handfull of valves. God knows why but probably the previous owner had not properly measured the clearence when replacing valves, springs, cams or whatever.

Also; my engine shake at idle has gone after re-timing the engine (which is necessary to install the correct valve buckets shims). It runs beautiful now! It was a chore but well worth the effort.

 

Hi,
I’ve been having the same issues with my 2001 XJR.
It makes quite a ticking sound and sometimes feels a little shaky when cold started, but perfectly fine in any other situation.

As I’ve also had sporadic P0420 errors when driving around 100kmh / 60 mph, I think it might be the exhaust leak you mentioned.
Where did you find yours? Must be in front of the cats I suppose?
While I’m at it, I would swap the lambda / O2 sensors for new denso units.

 

Reg. knocking sound from the back of the car:
On my X308 the annoying banging sound came from the rear shock lower bushes - I swapped them with my hydraulic press - and while I was there, I also swapped the "REAR SHOCK ABSORBER SUSPENSION BUSHING BUFFER", where I actually did not buy the expensive original parts, but I made something up using generic rubber or PU parts.

This is a picture of the original replacement parts:

On my Fairlane the annoying banging sounds were actually caused by those worn out parts in the picture above (obviously the Fairlane version).

 

I know the knocking sound from the back, which I also have. I already got the bushings and buffers for the rear shock absorbers, which I will change at a later date.

This cold start ticking is clearly from the engine though.
New Denso O2 sensors and NGK spark plugs have not solved the issue, although it runs a little smoother when warm.
The cats looked good from the inside, so the P0420 codes must have a different reason.
I had observed strange readings from one of the diagnostic O2 sensors, will check if these also appear with the new units.

Will probably move on to check valve clearance...