Engine mounts - how to ID time to replace?
 

This is related to a thread I just posted. I wanted to seperate the topics so the other one can be an ez quick reference for engine noises for folks down the road.

In the last month I have repeated problems of the cruise control's vaccum line dislodging from the bellows at the top of the throttle body. Can't figure out why it keeps happening but easy enough to plug right in when you get the amber engine failsafe an cruise control goes out. Last night it happened after wide open throttle & hard left turn.

I just had the snorkel work its way out of the air cleaner.

It just hit me, these are two items that connect to the engine from a body mounted surface. Could the engine be moving more than it should under hard accelleration? IOW - is this a sign that the engine mounts are not doing their job?

I hope this is pure coincidence, but figured I better ask. How does one diagnose engine mount problems?

Thanks I appreciate your thoughts.

John

That's exactly what's happening. If you want confirmation, the underside of one or both mounts have what appears to be ink running out of some drain holes. I'd replace both because they will cause damage to other things such as your transmission oil cooler aluminum tubes and A/C aluminum tubes on the left side (D/S for US cars) of the engine bay. Ask me how I know this. :D

Try revving the engine and watch for excessive engine movement. Also look for leakage around the motor mount.

The first indication is fluid leakage from the engine mount (the fluid looks black) the next is engine movement. Open the hood so you can see engine movement from the drivers side start the car and put it in gear with your foot on the brake and the emergency brake set gently bring your engine up to around 2000rpm and if the mount is broken you will see the engine rise. Be sure not to hold the engine at that RPM for long. Now this will only test for the left engine mount. I should mention that you do this in an open area and that no one is in front of the car, do not do it in the garage…

Link JagRepair.com - Jaguar Repair Information Resource

I just had my left one replaced, similar problem, the main air intake hose was regularly coming off of the throttle body. I also had a wear spot on the supercharger where it was rubbing against the underside of the hood, as well as fluid spots on the garage floor. Mount ran $188 with labor $220.

Thank you thank you. I just confirmed the mounts are bad. Will get them replaced. I appreciate having a $$$cost reference point as I walk into this.

Please post your costs, as I am working with a shop that only does Jaguars, and they tell me they can beat any dealer repair costs.

I was going through the service records on my XK8 and see that the Jag dealer replaced the engine mounts as part of the inspection and prep prior to selling the car at 7 years old and 84,000 miles (pampered California car). Just for another data point in how long they last. No cost shown as it was part of dealer prep.

My 2001 XKR shows a wear spot on the top left side supercharger body, but I have seen no other signs of engine mount problems. 90k miles. Is this fairly definitive?

I assume you have checked the mounts for cracking and fluid leaks. Even if not there, I would probably proactively replace at 90K miles, but I am no expert.

I have inspected and seen no signs there, and have had no issues with pulling free of hard mounted fittings, but perhaps I should do some more looking at the mounts themselves a bit more aggressively.


It is possible that the wear occurred prior to replacement, prior to my ownership. I have some maintenance records but suspect they are not fully complete.