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Porsche 911 Engine Mount Replacement
 
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Pelican Technical Article:

Porsche 911 Engine Mount Replacement

Time:

3 hours3 hrs

Tab:

$200

Talent:

***

Tools:

10mm/13mm/18mm socket, channel locks, floor jack

Applicable Models:

Porsche 996 Carrera models (1999-05)
Porsche 997 Carrera models (2005-08)

Parts Required:

New engine mounts

Hot Tip:

Follow the directions exactly.

Performance Gain:

Smoother shifting, better handling

Complementary Modification:

Replace air filter

One of the most common parts to deteriorate on the Carreras are the engine mounts. They are liquid filled and over time can develop leaks. They collapse once they leak and can cause a whole host of problems and cause wear to other critical components. Replacing the mounts isn't an overly difficult job, provided you have a floor jack and some basic tools. In this article, we will go over the steps involved with replacing the engine mounts on your Porsche 996/997.

Begin by opening the rear decklid and removing the airbox from the car. This will provide you with some of the needed access to reach the mounts. Please see our article on engine removal for more info (Pelican Technical Article: Porsche 911 Carrera Engine Drop). Once the airbox is removed, you'll see the right (passenger) mount easily. On the 996 Carreras, the left (driver's) side mount requires the removal of the emissions pump in order to access the mounting bolts, on the 997 there is no pump, and the mount is easily accessible.

Remove the emissions pump by first using a pair of channel locks to remove the hose clamp on the air line. Once free, pull the air hose off. Next, remove the two 10mm bolts and the 10mm nut holding the mounting bracket to the car. Rotate the pump over to access the electrical connection. Disconnect it and remove the pump from the engine compartment.

Now jack the car up and secure it on jackstands. Please see our article on jacking up your car for more information (Pelican Technical Article: Jacking Up Your Porsche 911 Carrera). Once the car is up in the air, you'll want to place the floor jack in the middle of the engine. The idea here is to use the floor jack to support the weight of the engine while you unbolt the mounts and replace them. Just jack the engine up until you take the weight off the mount.

From underneath the car, locate the two 18mm nuts on the underside of each mount. This nut holds the engine mount support to each mount. Carefully remove each mount when you are confident that the floor jack is supporting the weight of the engine.

Now move back to the engine compartment and remove the two 13mm bolts holding each engine mount in place on the rear engine shelf. Once unbolted, lift the mount up and out of the engine compartment. You may find that it's a bit difficult for the long threaded part of the mount to clear the engine support. Just carefully wriggle the mount out and place the new one in.

Open the engine decklid and remove the airbox.
Figure 1

Open the engine decklid and remove the airbox. Begin by loosening the hose clamp holding the boot to the throttle body (green arrow), then squeeze the tabs on the MAF connector to release it (yellow arrow). Now open the two harness holder clips (purple arrows). Finally, unbolt the 13mm bolt (996 only) holding the airbox inside the engine compartment (red arrow), if you have a 3.8 you will need to remove the wire connected to the vacuum resonance valve and carefully lift the airbox out of the car.

Here is a 997 engine compartment with the airbox removed.
Figure 2

Here is a 997 engine compartment with the airbox removed. You can easily access both engine mounts (red arrows).

Place a floor jack under the engine to support the weight once the mounts are removed.
Figure 3

Place a floor jack under the engine to support the weight once the mounts are removed. Be sure to use a piece of wood, rubber or newspaper between the engine case and the jack. In our case, there is a rubber pad on the top of the jack foot. Jack the engine up enough to take up the weight of the engine.

From underneath the engine, use a 18mm socket with a long extension to loosen and remove the nut holding the engine mount to the engine support bar.
Figure 4

From underneath the engine, use a 18mm socket with a long extension to loosen and remove the nut holding the engine mount to the engine support bar. Shown here is the nut on the left (driver's) side of the engine (green arrow).

Shown here is the nut on the right (passenger) side of the engine (green arrow).
Figure 5

Shown here is the nut on the right (passenger) side of the engine (green arrow).

Shown here is the left (driver's) side engine mount on a 996.
Figure 6

Shown here is the left (driver's) side engine mount on a 996. In order to access the two 13mm bolts holding it in place (green arrows), you'll need to remove the emissions pump (purple arrow). This is not necessary on the 997.

Remove the hose going to the emissions pump at the left of the engine compartment.
Figure 7

Remove the hose going to the emissions pump at the left of the engine compartment. Use a pair of channel locks to loosen and slide the hose clamp back (purple arrow). Twist the hose back and forth to free it up from off the pump. Then remove the two 10mm bolts at the front edge of the pump (green arrows) and the 10mm nut at the top of the air pump (yellow arrow). This nut also secures the front of the coolant tank to the car.

Rotate the emissions pump over to reach the electrical connector (green arrow).
Figure 8

Rotate the emissions pump over to reach the electrical connector (green arrow). Unplug it and pull the pump out of the car.

The right (passenger) side engine mount is much more accessible.
Figure 9

The right (passenger) side engine mount is much more accessible. Simply remove the two 13mm bolts). Once unbolted, lift the old mounts old and place the new ones in.

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Comments and Suggestions:
Viktor Comments: Hi! Thanks for a great site. My 996 C2 99' has had major vibrations on idle since I bought it in May. The mechanic has changed driving belt, link wheels, repaired the steering box and solenoids. Still a huge vibration. After having it in the garage for a week I discovered this brownish fluid under the rear left side. It's thicker than water, but prob. not motor oil. Engine mount fluid? Or RMS leak...?
August 4, 2016
  Followup from the Pelican Staff: I would check if the mount looks collapsed. Follow the leak to the source to see for sure what it is, look for a clean wet area, that will be your source. - Nick at Pelican Parts  
RetiredFM Comments: Wife's Tiptronic equipped 4S has developed serious vibration while in motion.
Checked CV joints and bearings and found them in good shape. Am I correct to believe that worn out motor mounts cause this condition?
June 28, 2016
  Followup from the Pelican Staff: Where is the vibration coming from? If from the engine, then yes the mounts are likely. - Nick at Pelican Parts  
JJB7 Comments: When reinstalling the mounts: ensure the old ones are both removed. Continue to raise the car until the engine carrier makes contact with frame or the car raises off the stands. When seating the motor mount, ensure the square on the mount seats into the square of the carrier. Otherwise you can never torque the stud and the carrier with float. Line up the top bolt holes ensuring the mount is properly seated, tightened bolts. Finally, tightened the 18 mm nut to 85 Nm. Lower car.
March 19, 2016
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
starionmike Comments: Thanks for your response. I don't buy the argument that you omit fastener torque data because "in the case they are updated." Torque data is of course fastener type dependent, however, the vast majority of your customers are using factory fasteners and/or the ones you sell. It is extremely uncommon for the factory to change torque data and when they do, you could up date your project table. Again, we are asking for factory torque data as a baseline...just would be extremely helpful from you guys the experts to advise us on this essential info.
Thanks again for all you do!
Mike S.
January 5, 2016
  Followup from the Pelican Staff: You don't have to buy it, that is why Pelican does it that way. I apologize if you don't like the answer, but I have to follow the rules. Repair manuals are the best place to find that info. - Nick at Pelican Parts  
charlie Comments: Most of your article are fairly good, but you don't include common issues and pitfalls; so many shade tree mechanics fall into traps that including these tips could easily guide us around. For example, many folks have the aftermarket exhaust systems. All of them place the O2 sensor bung too close to the drivers side engine mount bolt, so you have to remove the nearby O2 sensor. You have to have the special tool or you are SOL! Also, uniformlyI have notice that you omit the essential torque data for all of the important fasteners. It is not until someone asks that this essential data is provided. Why not just include a table at the beginning of each project that lists the factory torque settings for the main fasteners in the project? Also I noticed that most of your content comes from a published book by Wayne R Dempsey I am sure "by permission" of course. Thanks for all your efforts and hope my comments are taken as constructive for us all.
Best,
Charlie
January 2, 2016
  Followup from the Pelican Staff: We use Wayne's articles, because Wayne is a huge part of Pelican Parts, he started it!

We don;t supply torque specs in the case they are updated, best bet is to find them in a repair manual.

We try to add tips and tricks as we go. But we don't know everything, so at times it may look as if we omitted something, when in fact we were following the factory procedure and found it to work as is. - Nick at Pelican Parts
 
spikec2s Comments: My 2012 997.2 does not use a hex nut to secure the engine mount to the engine support bar. The fastener is a cylinder with what appears to be an internal torx See attached image. What is the size of this torx?
December 16, 2015
  Followup from the Pelican Staff: I don't know for sure. Looks like a T55 Torx, or T60. - Nick at Pelican Parts  
Wmj Comments: 996 2002 , just had new clutch and pedal helper spring installed , I notice
Slight shutter when starting from stopped ! Will engine mounts have any effect on this ? It seems like a relatively easy install and cost .
September 20, 2015
  Followup from the Pelican Staff: Could be, but most times the engine would vibrate at idle as well. - Nick at Pelican Parts  
Don't be this guy Comments: Wish I would have read this article first, especially aviography's tip to remove the lower nuts first.

I began by loosening the top two nuts of the passenger side mount. Huge mistake, and I don't know why I did this. Maybe because I was already up there getting the airbox out of the way. Anyway, I didn't realize that the top bolts need to be fully tightened in order to properly secure the post which hangs below which the lower nut is attached to.

After properly removing the drivers side mount, and seeing how the square bottom of the mount inserts into the square hole of the car's frame, I can only assume that I have stripped the square bottom of the passenger side mount! Yikes!

So, be sure to loosen the bottom nut first.

Currently, the mount is securely tightened at the top. The lower nut appears to be just about welded to the post. As I attempt to turn the lower nut, the post and rubber portion of the mount rotate freely.

If anyone has any ideas about how I might be able to remove the mount, shy of a flatbed to my indy... I am all ears!

September 2, 2015
  Followup from the Pelican Staff: You may have to cut the lower fastener out, then replace the mount. If spinning, no real option other than that. - Nick at Pelican Parts  
Undecided Comments: ...but also realized how easy it is to remove a Carrera O2 sensor : Thanks Pelican!!
February 13, 2015
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
Undecided Comments: Just a note...I have a FABSPEED exhaust and the O2 sensors prevent access with a socket.
February 13, 2015
  Followup from the Pelican Staff: Thanks for the additional info. We appreciate it.
- Nick at Pelican Parts
 
aviography Comments: There is no need to jack up the car at all as there is plenty of space to do this job without the extra step to jack up the car.

I used a relatively standard floor jack I've had for 20+ years with a strip of 3/4" thick oak hardwood floor piece on the jack saddle as cushion to raise and unload the weight of the engine, then simply unscrewed the various nuts and bolts as indicated in the above write up to replace the mounts.

Two tips I would like to share:

1. Make sure you have a 18mm deep socket before you start. My regular tool kit only had deep sockets up to 15mm, fortunately I found a 19mm deep socket in the Stanley Fat Max took kit I bought and keep in the Porsche, it was close enough to do this job,

2. Remove these nuts first at the bottom of the mounts, otherwise you may end up spinning the mounts while loosening the big nut below if you had removed the two bolts on top of the mounts first.
July 15, 2014
  Followup from the Pelican Staff: Thanks for the additional info. We appreciate it.
- Nick at Pelican Parts
 
AA717driver Comments: What is the torque required when bolting in the new mounts, if any?
October 15, 2013
  Followup from the Pelican Staff: I found a spec stating: Engine mount to engine carrier (M12x1.5): 85Nm (63 ft-lb) - Nick at Pelican Parts  
Hurdigurdiman Comments: There is no mention of jack stands used under the rear jacking points first and then to use the low profile floor jack to take the weight of the engine in this procedure. Simply use the low profile jack with the rubber pad enough to take the weight of the engine. Is this correct? Or should I use the rear side jacking points for the jack stands? In other words, is only the trolley jack used? Thanks.
October 14, 2013
  Followup from the Pelican Staff: I think I understand your questions.

First thing is to jack up and support the vehicle on jack stands. See our tech article on jacking your vehicle. Then you have to support the engine with the jack, I took this quote from the article,"Place a floor jack under the engine to support the weight once the mounts are removed. Be sure to use a piece of wood, rubber or newspaper between the engine case and the jack. In our case, there is a rubber pad on the top of the jack foot. Jack the engine up enough to take up the weight of the engine." - Nick at Pelican Parts
4wheels Comments: Extremely well done , and with photos to back up the discussion. Will be changing over when I redo the clutch later this year. Thx, Jon
September 17, 2013
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 

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