New Motor Mounts

Wow. What an immediately noticeable difference. 72K on my 2002 and gear changes were real notchy and there was a noticeable vibration at highway speed. Both completely cured. Not a hard job either, maybe an hour with the help of a PCA friend who had done his own recently. Do this if you have not. Soon.

This is definitely a must-do. Eliminated a ton of vibration for me. I did it at about the same point you did, 70k on the odo.

Did mine and it made a world of difference!

I did mine a month ago on at 57K miles on an '01 C4 Cab. The mounts looked just like the ones in rpm's photo. The symptoms I noticed were shaking seats at idle and a vibration that could be felt at certain RPMs. Both completely cured.

It's even more noticeable with poly version.

So where did you get your motor mounts from and what type did you replace them with?

I see parts geek has them for $95 and they are beck arnely, pelican for $160? Any thoughts on the Beck parts? I like $95 beter.

I don't recall what brand my replacement mounts were. I did get them thru Pelican and I recall them being right at $180 for the pair. There was no visible difference in the mount housing between the stock mounts and the Pelican mounts.

When you have bad motor mounts, are the signs and symptoms very subtle or pretty prominent. My car has 80K miles but I don't notice anything unusual to lead me toward motor mounts. I have replaced them before on other cars but I've noticed abnormal things like vibration or clicking or ticking or some weird noise when turning. But Porsche is new to me and I'm not that familiar with its behaviors.

I would characterize the symptoms as pretty subtle, at least in my case. I would not have known that I was experiencing worn motor mount symptoms (vibration) but for what I had read about other's experiences. I would have thought the vibration was normal. We took the Porsche on our annual fall drive, and with the concentrated driving time I could feel an engine vibration particularly at certain RPMs. This was pretty conclusive for me that the mounts were suspect even though I have relatively low miles (57K). I have a tiptronic, but those with manual trans often note some trouble with shift smoothness due to linkage being out of alignment and sloppy. And still others notice that their exhaust tips are drooped down.

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I changed mine at a bit less than 90k miles and I did not feel that much improvement. The rubber was elongated but not quite as much as the OP. One mount's rubber was a bit longer than the other for some unknown reason.

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My exhaust tips are pretty high up. I only experience harder shifts in 1st and reverse when the car is cold but once it warms up, everything is gravy. I think I'm good for now. Thanks!

I changed mine at 26k miles (12 years)! Made shifting easier, acceleration better, engine smoother, less vibration, etc. EVERY 996 owner should do it!!

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Same here and the reason why I switched to Poly versions which def was noticeable.

I think of these symptoms like the way a clutch wears out, slowly over thousands of miles. You adjust your driving without realizing it. And then after the new clutch (or motor mounts) you can't believe how much you were compensating for the worn out parts.

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There are a variety to choose from. OEM mounts are semi-solid; most upgrade/performance mounts are solid. I put a set of RSS Tarmac Series solid mounts in about a year ago and I'm really happy with them. Better shifting, better ride, better feel.

I read this post and rushed right out and bought 2 motor mounts. Mine looked exactly the same. After doing a test hop, I can report that the engine is much smoother above 3k RPM and according to the cell phone app, 1 db quieter. No difference in shifting. Dan Kansas City 2003 996 70k

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My work is done.

I installed the Function First mounts in mine two weeks ago. I had the vibration in the passenger seat at idle, but that went away. I do get some cabin vibration around 2700 RPM, but it goes away above 3000. Car feels a little more solid on takeoff from a standing start.

Just ordered motor mounts after reading this thread! Hopefully I experience similar results!

I have about 60k miles on my 04. Not sure solid mounts are right for me as I read they transmit too much vibration. What is the consensus mount to use when you don't track your car.

A few weeks ago the C4S was sluggish to turn over and the OEM battery was a tad over three years old. Thought it premature to need a battery but I considered it was on its way out. Voltmeter jumped right to 14 at start, as normal, so again I was thinking battery. While running multiple errands one day as I was near home I noticed the voltmeter hanging at 12 and not budging upwards no matter what. So I thought it was the alternator. I have a Porsche reman engine still under warranty so I decided to take it to the dealer to get it checked out. Dealer is about 13 miles away, mostly interstate, and the whole way there the voltmeter was showing a hair under 14, typical right? Car always decides to behave when it knows it is going to the dealer. I wait while the car is checked out and they say the charging system is working but the battery is weak and needs to be replaced. So I go for it and watch the tech install the battery and then run diagnostics post battery install. I can read the print out as it is printing and I see a charging system fail message. More testing and the tech says the alternator is bad, but it passed the initial diagnostic, so perhaps when it's hot it fails. Confirm it's covered under warranty so I leave the car there. Pick it up the a few days later and stop in the shop to thank the tech. He then tells me it wasn't the alternator but a bad cable. He found a TSB on 997.1 cars for the cable and since this is a Porsche crate motor the TSB applies. Turns out that when the cable gets hot it loses internal connectivity to the battery. I'm glad that I wasn't in a position to futz with a DIY as I can see myself befuddled after replacing a perfectly good alternator and not solving the problem. Wasn't crazy about going for the battery - but felt I got a fair deal at $188.00 installed and nice to know I have no worries around it now.

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I went RSS last year, to be honest,with respect to vibration I don't think there,s any real difference. However, there was noticeable vibration at first, but after week or so it smoothed out. Consider it a break-in period.

I put in Corteco. These are the stock mount. Dan

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My old ones were maybe 3/4" shorter. https://rennlist.com/forums/996-foru...l#post11596975

two questions about new motor mounts are the both sides with an identical part number (asking this due to the square shape at the end of the screw, that should align and fit in the engine bracket holes please can someon give the part number that is actually availalable and matches 996 c2 have seen: 99337504901 99337504905 99337504906 99337504907 99337504908 99337504909 of which the 09 is kinda turbo only, and all others except 06 are NLA thank you

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These are what I used for my 2002 C2 cab http://www.ecstuning.com/ES2550785/

Same part number for both sides. The bolt pattern only only lets you install one way. The ones I bought were -08. The place I bought them from thought this was the latest. Dan

This post prompted me to change mine too. As you can see, they were really shot, I believe these are the original engine mounts as the date code shows 03 2003 and mine is a MY 04. Now with 86k miles. Easy DIY!

120+ miles on a PCA drive today, mostly back roads. Not only does the car shift better and drive smoother, but the rear is more planted in hard cornering. More stable overall. Should have done this a couple of years ago. Hard to imagine anyone on their original mounts should not update now.

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Did mine with RSS mounts. It stiffened things up enough that I now have a couple new rattles. TC

Do It Do It Do It Do It!!!! Man - noticed the shifting difference immediately. I used to occasionally get a lag, or a bump when engaging 1st gear. I thought I was just not being 100 percent smooth on the clutch. Nix that idea - as soon as the new mounts were in, engaging first felt very very different. Smooth, clean, firm, and consistent throughout the travel of the clutch. I wish I replaced the mounts 20K ago. I used the standard replacement recommendation from Pelican. Easy swap. If you're thinking about it - stop thinking. Just do it. Rob

Give the mounts a few weeks to "settle in" and you may find some of the noises and rattles dissipate or maybe you just get used to them. Either way after 2 months with my RSS I find minimal NVH and can't even imagine going back to stock.

After my swap shifting was improved, NVH about the same, but the biggest change was in steering. Prior to the swap, I thought my steering rack had developed some play. It hadn't, the engine was bouncing around in turns.

I purchased new motor mounts as well for a 1999 996 C2. Same look of the old mount versus new--old very stretched out. When I installed the new mount, one of the 4 threaded bushings--outside bolt hole left side-- stripped out right away. I have had some weird noise during high g right turns and it's possible this is the source if the mount wasn't anchored properly. The threaded bushing holding the M8 x 40 is actually a see-through bushing--and only partially threaded with a lot of room to tap it all the way through and replace the 40mm with a longer bolt (55mm). It's a tight space to tap...attached is something I found--a t-handle tap drive with a sliding "t". I'm sure there are other gizmos that work, but just FYI. Also attached: photo of the unthreaded bushing with the M8 x 40 inside, and threaded thru with a M8 x 70 at the moment. So---what is the right torque for these--anyone know? Tom

Sorry about that photo--can't find a way to delete, make it smaller, rotate and put it up again. Geeze, that's annoying. OK, fixed it and added a couple...the edit button was scrolled off the page the photo was so large.

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18 ftlb from my memory.

That sounds right. The generic table for M8 grade 8.8 bolts is 18 ft lbs max permissible.