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Hey guys,
I know this has been discussed before, but I thought I'd add my experience. I have a 99 with 81k. I was changing the oil today and as usual, lifted the car from the rear engine jacking point that so many recommend.
I had seen discussion in the past about whether lifting from this point can cause problems with motor mounts, but never had the problem myself. Well, today I did, and about 1/4 cup of the hydraulic motor mount fluid came out!
Guess I'm going to replace the motor mount now. My take now is that jacking from this point can cause problems if your car is more than a few years old. Just my 2 cents.
One question: is it o.k. to drive on a leaking mount (not sure If I'll have time to replace before christmas). Thanks guys, Scott.
I'm not so sure whether it is the jacking that caused the engine mounts to fail. I mean, it is an eight year old car and the mounts do wear out over time. I just had the engine mounts on my 2000 Carrera Cab replaced a couple of months ago when I went in for my 100k service.
My take now is that jacking from this point can cause problems if your car is more than a few years old. Just my 2 cents.
I think Scott's (very valid) point is that while the jacking alone may not be the sole cause of the mount failing, it can be the straw breaking the camels back after several years.
So the new question becomes...where CAN we jack the rear from?
I agree that in this case, jacking the car up from the engine probably was not the root cause of the failure, especially on a car that is 8 years old. It would have probably failed on its own without the owner even knowing that it had failed. Now at least you know it had failed.
The good news is that these type of rear mounts are replaced mostly from the inside of the engine compartment, and is very easy to do. Essentially you take the bottom bolt of the mount off from the rear engine carrier, and then take the 2 bolts that hold the top side of the mount to the chassis off, pull it out, drop in the new one and replace the bolts.
I do not see how this would change the accepted way of lifting the rear of the car up from the engine case.
I think Scott's (very valid) point is that while the jacking alone may not be the sole cause of the mount failing, it can be the straw breaking the camels back after several years.
So the new question becomes...where CAN we jack the rear from?
Point well taken. The 8 year old engine mounts would have eventually failed and jacking the car probably made them fail sooner rather than later.
I am not an expert on the matter, but my Porsche mechanic adviced me to NEVER lift the car from the engine, not only because of the engine mounts were not designed to lift the weight of the car (only hold the engine) but because of the stress that it creates on the transmission-engine..
O.k., I've replaced the mount, and I've got to say, based on the amount of trauma visible to the rubber elemet of the mount, I can't believe this was "caused" by engine jacking. In a nutshell, the mount was utterly destroyed, as in, I could move the bolt up and down and squish it around as though it were a plunger in a toilet bowl...nothing like the replacement mount. The rubber looked like it had been bad for a very long time.
Based on this, my very unscientific guess would be that the mount was already bad, and when I jacked from the engine it changed the angle of the mount in such a way as to release the mount fluid. This conclusion is supported by the fact that I don't think you will see a visible leak when the engine is not elevated (the leaking stopped the second I let the motor down). The car also seems to be riding a little less harshly now that I've replaced the mount (although this could just be my imagination).
Thus, I no longer believe that the engine jacking "caused" the mount to fail," or even that engine jacking was the "straw" that broke the engine mount...more like the "straw" that revealed a pre-existing problem.
By the way, changing the mount was as easy as many noted...about 35 minute job.
I bought new engine mounts after looking under the car to see the okd mounts (original I think) were weeping Oil.
Jacked the engine up to take the weight and undid the mount. Easy to retract and replace. The engine fell about an inch and as it did the other original mount gave way and oil gushed out onto the floor.
big heart stopping moment - was it the mount finally leaking or an oil line sheered.
thankfully once the other mount was removed and replaced you could see the oily mess around the mount bracket on the chassis. Thank goodness.
ool cleared up and both mounts replaced - all good.
inspecting the original mounts afterwards they were oily, leaking and as loose as anything.
key takeaway - make sure you jack the engine up to take its whole weight so once one mount is removed the engine does not fall.....
I jack the car using the official mounting points and then put jack stands under the largest suspension part - it’s a 1”+ wide metal piece and that seems fine. I leave the jack somewhat snug as a backup in case.
In the future, you may want to consider Jack Point Jack Stands, which are designed so you can lift your car on the factory jacking location with a common floor jack and support your car on the Jackpoint JackStand using the same location used to lift the car. The jackpoint jack pad is designed to fit securely on the lifting plate of your jack. The pad is then aligned with the jacking location on your car, and the car is lifted with the pad in place.
Last edited by Formerly996fried; 05-27-2024 at 11:29 AM.
Since this is a 17 year old thread with some confusion back then approving of jacking the car up by the engine, to clear 2024 things up for those that might attempt this,,, this is not the way to go. Ever.
.Don't mistake taking the engine weight off the mounts by supporting the engine as the same as jacking up the car off the ground from under the engine.
Never jack up any car/truck by its engine. Conventional front engine mounts will stretch the rubber and rip it immediately/eventually. Some front engine mounts have steel tabs on both half's that interlock when rubber gets stretched, but imo still don't jack up car by engine.
The 996 mounts are designed for a 'hanging type pressure, not a compressed thousands of lbs pressure.
12-22-2007, 01:01 PM
Engine jacking resulted in motor mount leak!
