Motor Mount

[bar10dah]

When I changed my oil last week, I noticed a little bit of oily clear-ish fluid dripping from the front driver side of the engine. Yesterday, I took the engine cover off to inspect. Appears the last time I checked my power steering fluid, I may not have screwed the cap back on tight enough. So, cleaned up the mess and tightened the top down.

While in the engine bay, I noticed a bit of a wet spot on the top of the joint of my oil filler tubes. Both sides of the tube are new, mated together correctly, and the hose clamp is on correctly. The only thing I can guess is the engine was moving enough to create a gap at that joint? Okay, so my '99 with 75K miles more than likely has a bad motor mount. I'll have to order the motor mount, water pump, and low temp thermostat when I get back from my 2,000 mile trip. (going to SE VA for the weekend, attending Pancakes & Porsches in Chesapeake, if anyone else on this forum will be there too!)

How much should the engine move? I started the car up, and with the brakes on, revved the car up and slowly let the clutch out in first gear. Appears the engine would move up from it's relative location about two inches. Is that normal? Or another sign the motor mount is worn?

[harryrcb]

2" ist too much, your front motor mount is most likely the culprit, these have been upgraded a few times. Mine went at 40 k - fairly ease to change out. lots of write ups on this forum

[bar10dah]

Thanks Harry. I went to get a motor mount from the local dealer today. $149, not as bad as I thought. They said it's not a stocked part and would take 2-3 days to get one in. I'm busy on day 2 and leave at the crack of dawn on day 3.

Oh well, just have to replace it when I get back.

[bar10dah]

I forgot to mention, I've noticed when I accelerate quickly and upshift, when I push the clutch in, I hear/feel a thud coming from the rear of the car. Must be the engine dropping back down from rising up the ~2".

[bar10dah]

My motor mount arrived today. I ordered 987-375-023-05. However, 987-375-123-02 is what showed up on my door step. Any concerns?

[Wayne 962]

That's an old part, it's been superseded by Porsche to the more modern, updated version which is the -05. It doesn't look like you ordered it from us - we have that one (Genuine Porsche in stock for $142), and that one should be the -05 version.

Pelican Parts - Automotive Parts and Accessories - Porsche & BMW

-Wayne

[bar10dah]

Thanks Wayne. No, didn't order from Pelican this time.

I'm debating just using this older part instead of sending it back. I have another long trip coming up next week and would like to replace the motor mount before doing it.

Is there anything I should be concerned about, using this older part?

[bar10dah]

The rubber part says made in Korea on one side and 997.375.055.01 and 987.375.057.02 on the other. I wasn't able to find those part numbers in the PET or Pelican.

The metal says made in Germany and 987.375.123.02.

Correct part number for the most recent version is 987.375.023.05. Is this the wrong motor mount?

[Wayne 962]

I can't tell you as I didn't sell it to you. Don't mean to be rude, but you should ask these questions of the place you bought it from. The current correct mount should be 987.375.023.05. We have these proper ones in stock and can ship next-day air if need be.

The part numbers on your part may be casting numbers, or it may be an old part. Only the place that sold it to you would know - you'll have to ask them. I know that regardless of what the casting numbers are on the ones we have, they are the correct -05 part.

-Wayne

[bar10dah]

No worries, Wayne. I understand. The question wasn't really a Wayne, or even a Pelican, question. Just a general question for whoever may know the answer.

The metal mount part that came out had 986.375.123.04 stamped on the back and had 98 in a circle, so must be the original mount. My car is a '99. The rubber center has 996.375.055.05 stamped in it and also had a 98 in a circle.

I'm wondering if the part numbers on both the new and the old parts are the numbers for the individual parts, the mount alone and the rubber alone? And when you combine the metal with the rubber, that's where Porsche gets the 987.375.023.05 number from? None of the stamped part numbers listed on the actual parts come up in PET or Pelican.

Who knows, maybe I did get the most recent version of the motor mount. My invoice, from a dealership, does show the correct part number. I was just worried it was just an old mount they had on a back shelf somewhere. It does match the picture in my 101projects book, p. 36 photo 5.

Some additional info for those that are tackling this job with Wayne's book by your side, Project 10:

In photo 2, if the studs come out (all 4 of mine did) you can put them back in with a 7 mm socket. I wasn't sure just how tight to make them. I asked an ASE mechanic and he said just lightly hand tight.

The motor mount does come out/go back in without having to remove coolant hoses. Takes some creative maneuvering along with pushing hoses out of the way. Not easy, but it's very doable.

The rubber stops, as they're called in Bentley, are reinstalled with the tongue facing downwards, from the perspective of the mount as it sits on the car. If you're looking at photo 5 in the 101projects book, the tongues are pointing upwards. If you have an older style mount, they don't fit properly this way, as the center metal piece has been rotated on the newer mounts. But, just slide them on the best you can and they'll fit. The tongue keeps the mount from contacting the yoke.

In photo 4, retighten those bolts that attach the mount to the yoke to the tune of 48 ft-lbs.

When reinstalling the mount into the car, tighten the bolts that attach the mount to the engine to 34 ft-lbs. These are the horizontal bolts in photo 3.

Next, reattach the yoke to the body to 48 ft-lbs. These are the vertical bolts in photo 2.

Torque values taken from Bentley p. 10-16.

[bar10dah]

Old mount:



The top and bottom portions of the rubber are cracked all the way through. I'm sure this contributed to my motor lifting up and down as much as it did.