Finally decided it was time to bite the bullet and take care of some nagging issues with my '07 R52. There wasn't anything "wrong" with the car but there were a few things that just weren't right.

Well, I'm so glad I got that done. It wasn't exactly cheap but one trip to the shop made me wonder why I took so long. A new motor mount cleared up some vibration and harshness. New rear brakes really made a difference too and a flushed system improved petal feel. Other tune-up items just brought things back to where they should be.

Bottom line - it was 18 degrees this morning and I still couldn't wait to take the old guy for a spin.

I admit this level of a enthusiasm from a repair visit is kinda odd...but I'm sure some of you understand.

 

What vibrations were the motor mounts causing? At speed, at RPM ??
I have a vibration that I am chasing but it seems to be in the back or out of balance tires or bent rims.

 

I felt a couple of things:
- strong vibration at idle, especially when the car was in gear
- lurching during 1-2 and 2-3 shift under light to mid throttle

Nothing in the back of the car like you described. When coasting, the car was always smooth.

 

I can appreciate your new found love. The upper motor mount when failed is quite insidious. The car just ride crap, but very hard to put the finger on the cause. When it happened to me, I immediately thought it was driveline or wheel/tire related. I just happened to spot the brown stains by the mount when I was checking other things under the bonnet. When it failed the hydraulic mount still have a thin layer of rubber as the vibration shock absorber of last resort.

Once the mount was replaced with a real OEM, the ride is silky smooth again.

 

Exactly! For a while, I was almost convinced the transmission was starting to go...at least this was much cheaper than that.

 

It is easy to check if is the engine mount. Visually inspect the area around the mount for signs of brown stain that is rusty antifreeze water. The mount fails is open or shut case like if you puncture a water balloon.

 

I'll second that. Before I authorized the repair of the mount, my mechanic sent me a picture of the mount with visible dark dripping down the side.

 

Don't think it is antifreeze but rather hydraulic oil with rubber suspended within it.

Not 18 here today but did have my top down as well as last week on my trip to the Back of the Dragon and the Snake. Not to much better than the top down on a MINI (that has been modded just a little) on some great twisties.

 

I scrutinized the brown liquid rubbing between fingers, and it did not seem like it is oil base but water like. The brown stain on the painted surface is nasty and cannot be remove easily. My pepper white Mini is forever stained.

I wanted to cut one open to see what make it tick but the stainless steel housing proved to be too much trouble than I care to undertake. It will require a metal abrasive cutting disc, risking going to the emergency room for the heroic act in the name of automotive discovery.

 

I believe the facelift unit is described as a "hydraulic" mount by some vendors.

 

Hydraulic simply means contain liquid. It just happens oil is predominantly used in the applications because of many properties more suitable.

Here is a Mercedes mount cut open and the brave soul said it contain a smelly brown liquid that is water soluble. It would not surprise me the Mini one is very similar in design from the same OEM suppliers.

 

I've been reading up on the principles of hydraulic motor mounts. There are many variants of similar design. They mainly consist of two elements - a rubber spring, and a rubber bladder chamber that functions as hydraulic damper. Similar to suspension dampers the fluid is constricted when it passes back and forth between two chambers. Sure enough antifreeze is used.

Here is one excerpt:

Hydromounts from Vibracoustic offer the highest possible driving comfort. They combine the acoustic isolation function of a conventional rubber mount with balanced damping performance. In a hydromount, the main rubber spring has an upper and lower chamber. The chambers are connected by a series of canals and separated by a rubber valve. The mainspring is filled with hydraulic fluid which acts as secondary damping. On excitation or shock input, the rubber valve opens and closes the bypass channel redirecting glycol flow between the two chambers and changing the stiffness of the mount. To optimize the functioning of the grid, complex hole patterns are developed in painstaking test series to meet customers’ requirements.

 

As the vehicle is subjected to below freezing temperature the liquid would have to be prepared accordingly. On both my cars, the goo that came out was black.

 

Seeing so many different hydraulic mount all leak this dark brown goo, I wonder if it is added pigment by design. Like - OMG, what just happened!

 

Is there any other way to check this mount besides looking for brown fluid? My car is black and I washed the engine when I got it. I can't see any residue but I probably washed it away if it was there, and with it being black any stains wouldn't show.

 

The goo is very difficult to clean off so even with a black car I would think you could feel it if you rubbed your finger across the area.

The things last in the 20-30,000 mile range. How old is your car and how long have you had it?

 

I could not get mine all off, so I just used a factory paint pen and touched it up. That stuff is hard to get off and makes a mess.

https://www.northamericanmotoring.co...tor-mount.html

 

Me? My R52 has just under 53K miles and is 10.5 years old. This was the first time the mount has been replaced.

 

My stock mount died at 42,000 miles.