Exhaust rattle + rear motor mount

I remember reading somewhere that someone's exhaust was rattling, and it turned out to be the rear motor mount had gone bad. My P5 is doing something similar, and before I take it to an exhaust shop, I would like to inspect the rear motor mount.

After searching for hints and tips on rear motor mount removals, it seems everybody has a manual tranny, and I started getting the impression that the motor mounts for a stick VS an automatic are different. I could be reading those threads completely wrong tho. So I'm just curious if it's the same procedure (inspecting and replacing) for the rear motor mount of an automatic P5? Also, any guesses as too what a dealer may charge to have the motor mounts inspected and/or replaced? I may take the lazy way out of this situation since I'm busy with school. Thanks in advance...

same here....have the rattling...but it only happens when i've been driving for longer than 30 minutes +/-

i had my fiance put the car into reverse, then back into drive (because it seems to be worse when shifting between the two) and the motor really bucks quite a bit....now i'm thinking that the motor mounts may be a prob too

Onatrum said:

I remember reading somewhere that someone's exhaust was rattling, and it turned out to be the rear motor mount had gone bad. My P5 is doing something similar, and before I take it to an exhaust shop, I would like to inspect the rear motor mount.

After searching for hints and tips on rear motor mount removals, it seems everybody has a manual tranny, and I started getting the impression that the motor mounts for a stick VS an automatic are different. I could be reading those threads completely wrong tho. So I'm just curious if it's the same procedure (inspecting and replacing) for the rear motor mount of an automatic P5? Also, any guesses as too what a dealer may charge to have the motor mounts inspected and/or replaced? I may take the lazy way out of this situation since I'm busy with school. Thanks in advance...

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The rear motor mount is very easy to see up against the firewall directly below the throttle body. It is attached to the motor and not the tranny so I'm pretty sure it would be the same on an auto. My right side mount went first and then shortly after my rear went. But I am well over 200whp and I couldn't see a fairly stock set-up tearing them up very easily. While looking at the rear mount put some weight on the motor and move it up and down a little and you should be able to tell if it is in tact. It took me some exhaust tweeking over and over for about a month to get everything in their just right without rattling. I ended up putting some cable clamps around the exhaust hanger rubber grommets to keep it a little more firm in place.

I would definately not take it to the dealer. Replacement mounts are molded rubber into the bracket and come as an assembly (the right side anyway that I checked on). The right side is around $275.00 just to give an idea and I'm sure they would be anxious to rape someone. I made my own with some 2-part liquid polyurethane.

AWR makes 'auto' mounts and 'manual' mounts. I think this is the root of your confusion.

The auto mounts are a little softer = less vibration. The manual ones are stiffer therfore = more vibration.

I put the auto ones in my car as I like the dash to stay in place. You can replace the bushings.

The rear mount is a PITA to change so be prepared if you do it yourself.

Duct tape.

Could a torn rear mount explain why my exhaust sticks out farther after driving and my car is warmed up?

I have no flex section in my exhaust currently (soon). My racing beat tip looks bad after I drive because it sticks out a little bit too far normally and then when the car is warmed up it gets bad.

All metals expand when heated....I'm guessing 1/4 to 1/2" for the catback????

I guess I just never noticed it before I got the ractive header that pushed my exhaust back too far.

hmmm yeah it looks like I'm gonna have to try this myself. My exhaust has already been altered before because of the BC2 rear bumper. So I'm thinking that whatever was adjusted the first time might just be coming loose or something, but I didn't want to rule out a bad motor mount. Well I suppose I'll be spending some of my Easter weekend working on the car!