Trying to determine a cause of engine ticking in '95 XJ6, 122K miles. Normally I would think it to be valve lifters but it DOES NOT seem to be coming from valve cover area, rather from lower left of engine. Not relishing the thought of opening valve cover, particularly when I am not sure I need to be. Not much info that I was able to locate on this topic for this Jag and I am close to wit's end here. Suggestions are very welcome at this point.

Also, I hope I did this right but if not, my apologies up front.

 

Lee,

I've moved your question from General Tech Help to X300 forum. Members here with the same model will be able to help.

Graham

 

Lower left of engine, looking at the front of the car, or from the drivers side?

Also does the ticking happen at startup, after warm-up/running, and does it go away or sustain?


If on the RH side of the engine (while sitting in the car), and only happens at startup, it may be your upper timing chain tensioner. There is a TSB and replacement part for this.

.

 

Thanks for responding Al. The ticking comes from lower left of the engine while looking at the front of the car. There is a pulley down there but I have known them to squeak not tick. This happens at start-up, is continuous, and increases with RPMs. It is not as fast as a lifter would move.

 

So front lower RH corner is the "car talk" here. Always based on sitting in the car facing forward is what I was taught a very long time ago. This drivers side/passengers side is also flawed, depended on which side the steering wheel is fitted.

The a/c idler pulley, and or that flat belt that drives the a/c compressor.

The belts can crack and cause a tick.

The bearing in the pulley can tick, but usually just rumble.

The longbolt that secures that pulley to the adjuster bracket is known to come loose and the noise it makes could be called a "tick" I suppose.

The exhaust manifold is on the RH side of that engine, and they crack, and the noise of the xhaust gases escaping via that crack could also be heard as a "tick".

 

Note also that DOHC engines like these do not have lifters so it would be futile to remove the valve cover.

 

Thanks Grant for the info on a consistent reference point. Thanks Mikey for the 411 on the DOHC / Lifter things.

I'll look into the pulleys because I don't think it would be exhaust; the location of the ticking doesn't seem right. On the other hand though, I won't rule that out just yet. I changed the belts last year and they have less than 4K miles on them.

 

Oh, one more thing that might be helpful. The actual sound of that ticking sounds just like an arcing spark plug wire from an old Mazda truck I had -- just not as loud. I already checked into a bad spark plug or an arcing coil and found nothing abnormal.

 

Mmmmmmmm.

Out on a limb (my usual place), is the plastic drive adaptor INSIDE the power steer drive coupling. These can crack/fall apart and cause a clacking noise which I have never heard, only read about. You will need to remove that pump to check that plastic piece. Not a big, or hard task.

Lower timing chain dampers and guides are known to "break" and they do cause quite a strange noise, and "ticking" would be appropriate. Timing cover off for this one, so allow a day to do that.

Understand that the belts are new, but certainly worth a look, especially that A/C idler, as it was loosened to do that belt change.

 

Might be easier to suggest anything if you could take a short video and upload it to youtube or similar media sharing website?

I have also some sidenoise when cold

so is yours similar or not?

the sound does not increase in _volume_ when revving but the sound frequency is tied to the engine revs-

usually goes away when warm, so might be piston slap or not.

 

Hi leezcat, I would remove exhaust manifold heat shield and check manifolds for cracks, I've heard sounds from cracked manifolds that can sound very mechanical and as they heat up the sound either changes, softens or goes away as the crack closes up a little . My x300 manifold was cracked but welded up easily, but you need to read up on this. Failing that I would look into timing chain tensioner issues as both these items are known problems, hope this is of some help

 

Thanks for all who responded. I took the easiest place to start and that was the idler pulley. I replaced that it is sure was worn strange. I guess I should have paid more attention to that when I changed the belts after getting the car. Lesson learned there. Additionally, had to replace the AC belt again as it had started to split.

 

Well done.