so I had the car at my local indie jag specialist to have tierods and left front lower control arm done. ive had the car a couple of months now and have detected a vibration through the floor at about 50mph upwards. at certain speeds its it a throbbing vibration. I asked him to have a look at the driveshaft couplers and trans mount which he said looked fine , however he noticed one motor mount starting to leak and in general the both of them sagging a bit. he said that driveline vibe may be due to the change in geometry due to these mounts. question... would motor mounts going wonky be the cause of such a vibe? other than that , I have a bushing on the right lower control arm that holds the wheel carrier that is shot , and the rear links and tie rods all have boots with the rubber in bad shape - but no play yet. no sign of pinion bearing play / leaking. could it be rear half-shafts as well?

 

I think you would be well changing those engine mounts if they are leaking or fading away. 118k miles is a lot, (although these cars can, and do, get to 250k or more miles), and one must keep up with maintenance and replacements to keep the original ride. A supercharged V8 like yours will test the engine mounts much more than my fairly weak 3 litre V6.

There is also a rubber coupling at the rear of the prop shaft that can wear out.It is identical to the one on the S-type. There is apparently no separate part number quoted for the X350 cars. This could also cause vibration.

As you are finding out, the higher-powered X350 cars do stress the suspension components more. Which bush do you mean on the lower wishbone, the trunnion bush at the subframe end of the arm ? If so these are easily replaceable although some labour will be needed as it is a bench job to swap them. Usually the front one on the "banana" arm goes first, and can get so worn out the arm bangs on the subframe. Tyres also suffer wear on the inner shoulder as the wheels tow-out at speed.

Wear in the rear lower wishbone bushes is very common, and normally it is cheaper to just swap the whole arm as arm prices are now reasonable, (same as Lincoln LS), and it is quick so labour charge is less. Swapping out lower arm bushes has been known to crack the casting.

It has to be said, and is my experience also, that the suspension bushes are not long-life items on these cars. The steel ball joints do last a very long time but the other bushes can be wearing out after 30-40k miles.

 

the rear bushing is the lower are / outer one at the wheel. my plan of attack is to do the motor mounts first. mechanic said the shaft couplings looked good, but since they are inexpensive maybe I will replace them for good measure. those control arms are still almost $400 each side... so baby steps I guess

 

I replaced the large front bushings on both front lower control arms and did not damage the arm in the process. It was a simple project of pushing the old bushings out and pressing in the new ones. The bushings were inexpensive and I carefully marked the camber bolts before disassembly to keep the front alignment correct. It was an easy job with a press.

 

speaking of engine mounts, do any of you guys have recommendations on aftermarket replacements? or should I spring for it and go with the OEM? I saw a bunch on ebay but im hesitant to go through the trouble and put junk in there.

 

bump

 

I don't think you can get after-market engine mounts, as they are not a particularly fast seller. Mounts for my V6-engined model are around £95 (= $117) each from reputable UK Jaguar suppliers. Of course you have to add on shipping and tax. The SNG Barratt website for the USA has them for $150 each incl tax.

 

are a bunch floating around on ebay. various manufacturers such as "deutcheparts" etc. price difference is significant to oem , so was wondering.