While trying to discover the clunking in the middle of a turn type noises today I had my 2001 XK8 up on a lift.

The rear subframe mounts, the square rubber mount that is bolted to a plate with 5 torx bolts, appears to be dry and in poor shape in need of replacing.

Parts Geek as them for $90, but before tossing another $200 into it, I'm uncertain what they even do? Any ideas?

By the way, my clunk turned out to be an upper shock mount plate on the right top side that needed their bolts torqued.

Thanks

Doc

2001 XK8 Convertible

 

A square rubber rear subframe mount.............?

Graham

 

Well, perhaps my "Square" description wasnt accurate.

But it looks like this:

 

I'd first check out the sway bar bushings. They are active during turning, and are a known source of clunking. Next I'd examine the upper A-arm pivot bolt and bushings, then lower, then shock bushings and upper shock mounts. Otherwise, it could be all most anything in the front end. The mount you show could be the cause, but there are many other sources I would check before spending the time and money to replace them.

 

You missed the tail if my original post. The clunk was found to be traced to the right upper shock plate nuts needed torquing. Each one took about 1/4 turn to tighten up. Ive been chasing this for months.

Sway bar bushings replaced 2 weeks ago. They were both bad. End links removed and inspected. They were in good shape. Lower shock bushings replaced 4 months ago. Upper and lower ball joints good shape.

But I'm trying to determine if the subframe mounts are critical from a safety or future noise generation problem. Or how immediately they need to be replaced? Or especially their purpose?

Thanks,

doc

 

Sorry... I missed the gist of your question. The subject items are the subframe mounts. They attach the rear of the aluminum crossmember to the unibody frame rails. The crossmember supports the engine as well as the front suspension... So yes they are an important part.

The four smaller bolts attach the mount to the subframe and the center larger bolt attach the unibody. The rubber holds everything together.

 

Ah! Now I get it. The Front Crossbeam Vee Mounting (item 3):



Jaguar used to fit metalastik Vee mounts on earlier models. These are prone to de-laminating, in the worst case ending up with metal to metal contact between the body and the suspension resulting in transmitted vibrations.

The XK8/XKR Vee Mountings are an alternative design to try to remedy this failure. Instead of metalastik, the mountings are gel filled. They last much longer but can fail with the gel leaking out.

Graham

 

I am looking at a spare crossmember right now in my garage. The rear 'vee' crossmember mount is not silicon filled. The center mounting hole is bonded to a section of solid rubber cushion about a half inch thick. This is rubber is then bonded to the perimeter 'square' section containing the four bolts which join it to the crossmember proper.

The front round mounts might be silicon filled, but not the rears... it is plain to see they are solid rubber. Regardless, we are splitting hairs here... they are a critical piece on the car, and if they break, there will be fearful noises, probably some vibration, and lots of gnashing of teeth going on.

 

I knew there was a reasonable explanation, and this explains it all now.

The front ones look decent. The rears are far from it. Although there's No strange vibrations that are out of the ordinary yet. I will bite the bullet and toss more money and parts into it.

I love the car, but hate the constant parts replacing.

Thanks for the great reply and information!!


Doc