My 2000 XJR was in for its regular service at the local dealership and the service advisor pointed out that all the front 5 mounts in my vehicle were in need of immediate replacement. I have changed the 2 Engine mounts coupled with the Transmission mount, but still feel a clunk or rough ride over any and all bumps. I have been searching on the forum and Google and needing some direction as to how many subframe mounts are in the front. I am coming up with a V mount and round mount in my search so am arriving at 4 mounts. Also, what might be the best way to ascertain which one is the offender?

My second problem is faint fuel/gas smell from the engine bay, more concentrated towards the passenger side of the engine. Is there any correlation between the damaged subframe mounts resulting in all the bumps and movement that is causing the smell? I had the vehicle running whilst stationary after getting home and not picking up any smell. If this is not tied to the mounts and is an injector problem is it something that can be tracked at the dealership with a scanner? I am just trying to avoid 6-7 hrs down on the diagnosis.

Appreciate any input.

 

Mr Brit,
This might not be the same as your car since the gas smell comes from the engine compartment but I had a gas smell from my 99 xjr that seemed to move around a little. Sometimes it seemed to be up front, sometimes the rear. It was definitely more prominent on the passenger side though.
I got under the car and found there's a vent solenoid on the second charcoal canister, located on the passenger side. Above the solenoid is a vent tube and filter, probably to make sure something doesn't get into the canister, rather than out.
I replaced that solenoid and the gas smell is gone. You might just see if you can pin-point the smell a little closer. Could be the same issue I had. BTW, there were no codes for evap leaks, just the gas smell.

 

4 mounts is correct. Jack up the car while watching how much the sub frame lowers as the wheels leave the ground. You will be able to tell if the front V-mounts are torn or intact. Doubtful that the rear round bushing have failed but you can check them the same way.

Rough ride and clunking is common when the upper and lower shock bushings and/or the anti-sway bar links have failed. Have you checked them?