XuTVJet

Back in November 2022 I replaced the engine and transmission mounts on my 2011 Cayman Base. The mounts were shot, especially the engine mount which was torn and causing heavy vibration. It was the original mount. When I got the engine mount uninstalled, I saw the flappy rubber pieces on either side of the center part of the mount and some seriously degraded flappy foam pieces next to the rubber These parts are known as the engine mount "stops". https://www.pelicanparts.com/More_In...hoC7akQAvD_BwE

For the 987.2, they are two piece stop that has a rubber and a foam component bonded together. I believe the 987.1 was originally a thick piece of rubber but was updated to the rubber/foam arrangement. The foam degrades over time from engine movement and such. The foam parts on my original mount were 80% gone. At the time, I did not know that these stops were an integral part to the mount and I simply reinstalled the original stop with just the rubber stop and tossed the foam. I didn't think anything of this as Japanese cars I've worked on the past two decades often had thin rubber flappy pieces and their only job appeared to keep dirt out of the rubber main mount. With the new mount and old stop, the engine vibrations were quite reduced at first. However, after about 2 weeks and as the rubber in the mount loosened up a bit, I started to feel some minor vibrations and general graininess on cold starts and through the rpm range, especially at 1900rpm and a bit 4000rpm whether in neutral or when driving. There was also a faint, but obvious thud on the 1-2 shift. The vibrations weren't terrible at all, but I was surprised that a Porsche would have this amount of vibration/graininess. A few months later after reading forum posts, I figured out that foam part of the stop helps isolate minor vibrations and is integral to the mount.

After about 8 months of putting it off, I finally got around to dropping the engine mount again and installing new stops a few weeks ago. Wow. What a difference those little foam pieces make. Gone is the vibration, graininess, and 1-2 shift thud.

Why did I put it off so long? Because getting the mount out and back in is a royal pain, at least the first time I did it. Getting the bolts out is easy (three from under the car and one through the front engine access). The problem is the two coolant hoses that sit below the mount and the width of the mount itself. It's a seriously tight fit and the first time I did the job, I squeezed, stretched, and manipulated the coolant hoses like hell to get that mount out and back in. I really thought I was going to tear a hose or crack a coolant pipe. One of the coolant lines at the connection point to the motor actually temporarily leaked at its O-ring because I was bending them so hard. This time around though, I worked smarter, not harder. I removed the central lower body panel and removed both cross braces that secure and hold the coolant pipes in place. There's one brace just aft of the engine mount and another one just under the area where the shifter is. On my first removal/install, I only removed the brace aft of the mount. This time I removed both. By undoing the braces, the coolant pipes/hoses, will drop quite a bit more thus giving you a lot more room to get the mount out and back in. It's not remotely as difficult to install once you do this. I had the mount out in 30 seconds and back in within a minute and nothing was being taxed.

So long story short, check those engine mount stops. The condition can be assessed by simply getting under the car and looking. These parts are definitely required if you want to keep NVH at bay. I imagine the foam on the stops only last 5 or so years before it starts to degrade as the middle part of the mount really does torque around a lot.

Dave in Chicago

Thanks for posting this. At north of 140k miles, I’m likely due again for engine mount refresh (had one done at shop long time back) and suspect the trans mounts are far past their life on my car.

Gatornapper

Wow. Scary. Another problem I need to look out for in my 109k 987.2 S as I am replacing plugs and coils this week.

I have my own shop with lift but still not looking forward to this after your description.

NO vibration at all presently.

GN

dave_987

Thanks XuTVJet, your post is so helpful, I am planning to do this job soon. Hoping you can help with a couple of questions. Did the new stop have both the foam and rubber together as one piece or do I need to reuse part of what’s already there? How are the stops oriented? And if possible what was your trick for supporting the engine while you did the swap?

Spyder_2011

Thanks for this post, I’ve heard the engine mounts do not last very long. I had my mechanic check the engine mount and they noted that it was fine but I really want to get under and check it myself. Did you take any pictures of your worn out mounts?

I did change the transmission mounts which made a big difference in shifter feel and the overall cars tightness which surprised me.

Apex1

Check out Function First engine motor mount inserts for either 987.1 which I have and 987.2. I originally thought my engine needed the stops filled in as Function First insert does, but while in the shop, the mechanic told me the OEM motor mount was shot. Luckily, they were able to grab one from their parts vendor and have it delivered within an hour. Then they replaced the new mount with the FF orange insert in place. What a difference, but their is a NVH cost. More engine vibration and noise, at least for about 3 months, then almost back to normal. I waited another 3 months and added the orange transmission mounts as well. There did have more NVH, but again they settled down after about 6 months to normal. So, the story is if you want to add a tighter mounting system, which helps prevent engine weight transfer around corners, give Function First a call. You should be prepared to switch out the old motor mount as its 90% shot by the time you wait to change it.

Apex1

I used the orange insert which is the softest insert along with t new oem motor mount to secure my floppy engine,

MrMoose

I think you may have done it the hard way. I followed the instructions someone else posted and just disconnected the large right coolant hose to get space to R&R the engine mount. A little coolant came out but a LOT less than you'd expect (like half a gallon) and I didn't need to bleed the cooling system or anything afterwards, just topped it up.

At 60K and 8 years the engine mount on my car had some cracks but wasn't trashed. The transmission mounts were pretty shot and sagging, though.

XuTVJet

Yes, they are single piece and the foam and rubber are bonded with glue. Regarding orientation, it's the foam side facing inwards and the rubber outwards. Pelican Parts say differently, but mine were orientated with the foam towards the inside and numerous Ebay listings of used OEM mounts show the foam mounted inwards as well (see attached). The zoomed in attached photo is my original mount before removal and you can see the degraded foam facing inwards.

Regarding hold the motor in place, I used a floor jack with the piece of wood under the oil pan. Next to the jack I had a jack stand pushed up within 1/8" of the pan just in case the jack gave way.

XuTVJet

This was my engine mount at 67K miles. Completely torn in multiple spots. With the stops in place, there's no way to check if the mount is torn or not.

Removing the coolant hoses is certainly the easiest way to do it, but I didn't want to bother with coolant stuff as I plan to replace the coolant in the summer plus dropping the two center supports made all the difference in the world the second time around.

dave_987

Thank you @XuTVJet !! I am going to follow your lead to support the motor, I believe in redundancy too ! 👍

RJ80

At 38k miles I have just a bit of vibration noticeable at idle. It's not enough to rush into it yet, but I'm guessing this job is in my not-too-distant future as well. Thanks for the write-up.

Zepper

Just reviving an old thread....
XuTVJet were the transmission mounts you replaced the ones that Pelican sells for like $217 (manual) each or is there a cheaper source for them?

My 2009 manual base box (42k) miles has quite a heavy engine shake at idle, especially on cold startup. So i already have the motor mount and was planning on doing that soon.

XuTVJet

I bought the OEM mounts from FCP Euro. They are $225 each. It sounds like the ones you're looking at Pelican are likely the same ones.

It is my understanding the engine mount and/or a failing dual mass flywheel are the primary sources of engine vibration while in neutral and not the transmission mounts. I had both. If your transmission mounts are the originals, then yeah, go ahead and replace as they are likely collapsed. My transmission mounts had collapsed about 1/4" of an inch compared to the new ones.

Zepper

Ahh good to know re: the possibility of the flywheel failing.

Honestly i have not looked at replacing the transmission mounts yet (or even checked mine), it sounds like they can be done separately then the motor mount? Just wondering if there is time overlap that would make sense to do it at the same time as the motor mount vs. doing the motor mount (which i already have on hand) and seeing if that fixes the vibration issue and if not then going back to replace the $450 worth of trans mounts. If they were $50 each i'd just throw them in but at $225 each i'd want to know they were worn.