Hi Folks, I have a slight vibration at tickover if the car is in reverse or drive. I think it is failing engine mounts, thge vibration goes away on very long runs, I suspect as the rubber components get wamr and soften a bit. Has anybody else experienced this or changed the mounts? If so how hard was it and did it fix the problem?
Thanks in advance.

 

The mounts should be fluid filled.

Are they leaking?
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Hi, Yes, they are hydraulic but I can not see if they are leaking or if they have leaked in the past.

 

You can change them if you want but unless the fluid leaked out they should be fine.
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I've been told that the fluid is purple or blue in color....

 

If they are original to the car they are more than likely bad. If you can get under the car for a look the purple fluid will have left stains on the outside of the mount if it has leaked out.

 

Thanks for the replies, guys, will have a look at some time and see if I can see any leakage. I am a bit doubtful though as the previous owner had it incredibly thoroughly cleaned before I bought it.

 

They seem to last a long time and only a few people have replaced them.

Have you done the old DIY trick to check them??

Did find an interesting bit of Jaguar trivia. The newer XJ's have active motor mounts to counteract engine vibrations especially at idle.

I would hate to see the price for an active motor mount!
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[QUOTE=tbird6;1217161

Have you done the old DIY trick to check them??


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Sorry but I have no idea to which DIY trick you are referring, please enlighten me.

 

I don't have personal experience with engine mount repair but from what I read in this forum from others who've done it, it seem not difficult. The steering rack was not loosened and subframe not lowered. People seemed to have done the replacement simply by loosening the both engine mounts + transmission mount and jacking up the engine enough to get the old engine mount out.

The engine mount top nut is accessible from top side, it's visible with hood open, and the bottom fastener is accessible from bottom side.

Since the torque is applied to the right side mount predominantly, it's likely the RH mount need repair before the LH mount does.

I wish I could speak from experience however to be more concrete.

And tbird6, explain what you mean by the DIY trick to see if the mount is shot.

 

What us shade tree guys do is this;

Open the hood so you can see the engine from the driver's seat.
Then start the car and put it in gear.
Then carefully hold the brake and push on the gas a little bit. This will use engine torque to try and lift the motor out of the car.
Use more gas pedal if you think you see something move.

Watch what the engine is doing. Is it just twisting a bit on the mounts or does it try to raise up? With a broken mount I have seen the engine raise up so far it would hit the hood!

But that will only compress one mount and place the other mount in tension.
Now put it in reverse and do the same thing.
Doing it this way you have pushed and pulled on both engine mounts using engine torque.

Just compare the amount of engine movement in reverse and drive. The movement should be the same in both directions if the mounts are all good.

Now as you might guess this won't be 100% but it's easy and quick and takes no tools.
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I had my passenger side engine mount replaced last year- as tbird6 pointed out my engine was pivoting when idle increase -moved a shocking amount really. I had my transmission mount also replaced as I am getting much drone inside the cabin-that helped a lot but it is still droning under accel- no where near as quiet as when I bought it 5 years ago-I'll look at the other engine mount and well as the diff mount next

 

Did your motor mount leak?

How much was the new one?
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About the only thing that has failed on my STR due to years of racing is a driver's side motor mount. The track was not prepped well and wheel hop caused my motor mount to fail.

As they said, you will see a dramatic lift of the engine when the mount has failed. I purchased a Motorcraft part (~$30 if I recall correctly) and all was as good as new.

 

I think it was $130 from Jaguar and an hour to put it in- and yes it was torn and no fluid inside-don't remember if I saw evidence of a fluid lead, but as I don't do my own work I didn't look at it for long.

 

Thanks guys, will look at it some day when the weather is a bit better. In the mean time I have an intermittent multi cylinder misfire to sort out.

 

Glad to hear the mount was only $30! That is almost cheap.
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The passenger side is easy the drivers side not at all and most r's i have to lower the subframe bolts to to get extra clearance ater the rack is unbolted from frame and engine jacked up. Yes the fluid is a dark purplish color and stains it does not wash off. So dont wear anything good if youre under the car. The trans mount is the same. But they easy to change and cheap too

 

I had an engine mount replaced two years ago when I had the transmission rebuilt. The mount was completely broken.

 

for LHD STR owners

fact 1: subframe does not need to be lowered

fact 2: rack does not need to be dropped

fact 3: when using some brands the top stud is longer than factory and must be cut