Hydraulic Motor Mount

[Chuck996]

In the process of a brake job --- tried putting a floorjack under back area of the engine. A solid area -- jacked up a little and noticed oil leaking out of what appears to be left motor mount. Lowered the car and found new jacking point. Oil quit leaking.

Did I do much damage????? Everything looks ok when engine running.

Thanks,

Chuck in Myrtle Beach

[RFM]

The engine is not a jacking point, you have to replace both engine mounts. There are instructions on this board concerning jacking points, do a search.

[londoner06]

Chuck,

This is probably the most popular of the 'jacking' threads:

http://www.renntech.org/forums/index.php?s...ost&p=16250

As RFM suggested you can get tons of info doing a quick search, just click search and enter:

jackstands

The main point about using the jack to raise the back of the car is that it is done just long enough to put jackstands under the rear jack points.

Alex

[Chuck996]

I did follow the above procedure. When using the rear of the engine point is when I experenced the hydraulic fluid. How much fluid does the motor mounts hold????

Has this happened to any one else????????

Thanks,

Chuck

[Orient Express]

The liquid filled motor mounts on Porsches, Audis, and VWs, are notorious at failing. The usual indication of a failed mount is that you will see a greenish or purple fluid stain on the mount. The majority of these types of liquid filled motor mounts will fail by the time the car has been driven 100K miles. Even less if the car is driven consistently in an aggressive manner or in adverse conditions.

Now contrary to the "experts", temporarily lifting the car by the engine to place jack stands on the rear lifting points is not the root cause of the rupture of the mounts on a 996/997. The root cause is simple fatigue of the elastomeric material used to manufacture the mount.

If a mount actually fails during the lifting of the car, that is the preferable way to have the mount fail, as it was going to fail regardless.

It is better that the mount fail when it can be noticed, than it fail silently and it be many miles until it is discovered. Indications of a failed mount are:

- purple or greenish fluid stains on the mount or rear engine cross-support.

- Increased vibration or engine harshness

- The engine sitting lower on one or both sides.

Good news is that replacing the mount is a simple half hour DIY job, with each mount costing less than $125 each.

The mount is replaced from the engine compartment, with 2 bolts holding it in place on top, and one on the bottom. Simply hold the engine up with a floor jack, remove the lower bolt, then the 2 top bolts, lift the damaged mount out from the engine compartment, drop the new mount in, and replace the bolts.

The mounts should always be replaced in pairs as if one has ruptured, the other is not far behind.

I recommend that any 996/997 with more than 40K miles on it be inspected for mount failure during routine maintenance.

[juddtaylor]

I did follow the above procedure. When using the rear of the engine point is when I experenced the hydraulic fluid. How much fluid does the motor mounts hold????

Has this happened to any one else????????

Thanks,

Chuck

Me too, at about 65k miles. Following the same jacking procedure. Mine failed, and I happen to know that a hot 3-day summer track event (in TX) caused the failure. Those things usually get hot, and due to the oil and rubber inside, hold the heat inside for a ridiculous amount of time (3-4 hours, at least).

I replaced them with semi-solid units, which lasted like a week before I put new OEM mounts back in. Happy ever since.

-Judd

[londoner06]

OP.

Thank you for your excellent, informative, and well-written post. I have followed your DIY directions for raising my car several times this year without any problems.

Alex

[bmohr]

i replaced my motor mounts today and after I was done the left side sags a little down more than the right:( Whats up with that? Also the left side extends further from the car now too. Wtf did i do wrong? All i did was remove and replace. Anyone else have a similar issue?

[Purplxd]

That happened to me too and I went with the solid RS mounts. My exhaust tips are a bit off in alignment now so will need to fix that...

Cheers

Aaron

[bmohr]

is it possible that i bent the cross member that holds the mount out towards myself when pulling on the wrench to break the bolt free on the mount? I had to pull with all my strenght for 15 minutes before it finally gave. Hmm...I now see that piece of metal is fairly "loose" or it wobbles a bit when i un screw the mount. Is that normal? Or did i do some damage torquing those nuts off? Another easy job turn PIA.

[Benjamin Choi]

Anyone have the part numbers for all the motor mounts needed to do a full replacement of the originals? I'm just going get new ones at 57K miles.

[Loren]

Anyone have the part numbers for all the motor mounts needed to do a full replacement of the originals? I'm just going get new ones at 57K miles.

993.375.049.06 Motor mount -- US MSRP $155.30 each (2 required).

[Benjamin Choi]

Anyone have the part numbers for all the motor mounts needed to do a full replacement of the originals? I'm just going get new ones at 57K miles.

993.375.049.06 Motor mount -- US MSRP $155.30 each (2 required).

Here's what I was quoted by Phil Coy at Sunset:

993-375-049-06 mounts $129.55 ea. X 2

999-084-215-09 locking nuts $1.15 ea. X2

Loren and Phil both work at light speeds. :) Thank you!

[perryinva]

Is it OK, or even possible to use an impact wrench to remove the MM nuts? One of mine looks to have oil on it, but it may not be leaking.

[Orient Express]

Anyone have the part numbers for all the motor mounts needed to do a full replacement of the originals? I'm just going get new ones at 57K miles.

993.375.049.06 Motor mount -- US MSRP $155.30 each (2 required).

Here's what I was quoted by Phil Coy at Sunset:

993-375-049-06 mounts $129.55 ea. X 2

999-084-215-09 locking nuts $1.15 ea. X2

Loren and Phil both work at light speeds. :) Thank you!

This is correct. 993.375.049.07 are GT2 and turbo mounts.

[vrex]

is there a problem using semi solid mounts in a 2002 c4s? what mounts are even available? i would suppose anything gt3/rs would fit, but not turbo items? instructions for this procedure said support the engine with a floor jack... need i add a 2x4 between the engine and the jack? where should the jack pad be centered on? i am guessing i ruptured a mount because i jacked the engine up from the rear jack point. any helpful hints and tricks to getting this done would be appreciated.