Why do cars have rubber engine mounts?

[oil_film_movies]

Originally Posted by das_peikko
So what you guys are saying is: If your car already has rubber engine mounts and you're STILL getting vibrations, you got serious problems!
Just means you need new engine mounts, thats all. They go out at times. Crack, hydraulic ones leak.
https://bobistheoilguy.com/forums/threads/motor-mount-hydraulic-or-solid-rubber.193420/

 

[pezzy669]

Originally Posted by Wolf359
Originally Posted by Michael_P
Years ago, I removed the rubber engine mounts and suspension bushings from my GTI and replaced them with Urethane. It diminished the day to day driveability of this car. At first, I thought urethane felt better. But after a few thousand miles, the added vibration got annoying. And to think some of the highest performing cars of today use rubber mounts. For overall comfort, noise and vibration isolation, you cant beat rubber mounts.


Actually Mercedes tend to use liquid filled motor mounts. Only drawback is that they eventually crack early and the liquid flows out and then the vibrations are even worse. But they're great when they're working right. You end up with a very smooth and quiet ride.


^This

They make them so they are great for the when new test drive then the CPO drive ~36k miles later once the car comes off lease. Then lets say 75k-100k mile mark they are shot. C300 in my signature they were at end of life when I traded it in, only to trade for the E350 which has engine mounts that are probably 15% away from rattling my teeth out. Dealer quoted $2300 for the 2 engine mounts and trans mount - the independent I am going with quoted $1250 - 4Matic requires the exhaust manifolds be disconnected to replace the mount.

 

[clinebarger]

Originally Posted by PimTac
Some cars use liquid filled mounts.

...±...±...±


And some are Liquid Filled-Active Mounts that have Vacuum applied to them under certain load conditions.

All my high performance 60's GM cars & trucks would break the left mount if I didn't use a limiting chain from the frame to the left cylinder head. My 1966 Impala SS 396 had dealer installed limiting crimped cables that didn't stand-up to a warmed over 454! I tried running a solid left mount....One day of that was enough!

 

[Wolf359]

Originally Posted by pezzy669
Originally Posted by Wolf359
Originally Posted by Michael_P
Years ago, I removed the rubber engine mounts and suspension bushings from my GTI and replaced them with Urethane. It diminished the day to day driveability of this car. At first, I thought urethane felt better. But after a few thousand miles, the added vibration got annoying. And to think some of the highest performing cars of today use rubber mounts. For overall comfort, noise and vibration isolation, you cant beat rubber mounts.


Actually Mercedes tend to use liquid filled motor mounts. Only drawback is that they eventually crack early and the liquid flows out and then the vibrations are even worse. But they're great when they're working right. You end up with a very smooth and quiet ride.


^This

They make them so they are great for the when new test drive then the CPO drive ~36k miles later once the car comes off lease. Then lets say 75k-100k mile mark they are shot. C300 in my signature they were at end of life when I traded it in, only to trade for the E350 which has engine mounts that are probably 15% away from rattling my teeth out. Dealer quoted $2300 for the 2 engine mounts and trans mount - the independent I am going with quoted $1250 - 4Matic requires the exhaust manifolds be disconnected to replace the mount.

They were shot on my W211 at 60k. On the W212, you can get the aftermarket ones which are supposed to be the OEM makers for MB for about $100 a mount. That $2300 quote is probably a few hundred for the mount itself. The transmission mount is nothing, took like 10-20 minutes for my indy to swap it out.

 

[Trav]

Originally Posted by Michael_P
Years ago, I removed the rubber engine mounts and suspension bushings from my GTI and replaced them with Urethane. It diminished the day to day driveability of this car. At first, I thought urethane felt better. But after a few thousand miles, the added vibration got annoying. And to think some of the highest performing cars of today use rubber mounts. For overall comfort, noise and vibration isolation, you cant beat rubber mounts.


The one mount you can do in urethane on a VW that really improves shifting is the lower dog bone but you have to be careful which durometer you use.Power Flex has a street compound (yellow) for the rear part of the mount and purple for the front bushing. The feel like a new OE mount but don't deteriorate over time like the OE.
The other mounts must remain rubber, urethane will shake you out of the car.

The other mounts that work well with urethane is the old style strut donuts and rear beam bushings, Power Flex makes the best on the market bar none, again they feel like new OE all the time and never compress or get sloppy and the car holds alignment especially in the rear, shimming the rear hubs gets old fast.

https://www.powerflexusa.com/

 

[supton]

Maybe you could give up the rubber mount, assuming you have something like a V16 under the hood. Although I do believe Packard had some massive inline 8 which idled dead smooth--it should have, it was a massive low compression cast iron behemoth.

 

[StevieC]

Some have fluid filled mounts instead of rubber (synthetic material) mounts.

 

[aquariuscsm]

My 300ZX's manual shift lever comes to mind. Smooth as silk with oem rubber mounting bracket. I'd replaced it with a solid metal bracket and it vibrated like crazy and shifts were notchy. I could feel and hear every vibration from the transmission. I immediately went back to the oem bracket.

 

[Lolvoguy]

Originally Posted by StevieC
Some have fluid filled mounts instead of rubber (synthetic material) mounts.

Yeah, had one of those on my 07 Focus.
They had a tendency of failing early and causing all sorts of NVH issues.
But even when the mounts were new, the car felt cheap and trashy.