I have a 2006 RL with 187,xxx I just took it to my mechanic and he replaced all 4 motor mounts, the front, back, side, and transmission mount.

Before replacing them, the it was very smooth and you could not even tell the car was running. The new mounts got rid of the occasional clunking noise and the motor no longer jumps when shifting through gears. The old mounts were broken.

But now, after new mounts, it vibrates when in D with the foot on the brake. It vibrates enough that I can hear a buzzing and it makes my glove box rattle. You can't see the steering wheel shake, but you can definitely feel it. As soon as I accelerate or take my foot of the brake, the vibration is gone. Any other gear it idles extremely smooth.

My mechanic is telling me its normal. I asked him why it didn't vibrate before and his theory is that the old mounts were squished so the motor could not vibrate and now with the new rubber on the new mounts, the motor now has room to vibrate. He also said that its common for older cars to vibrate with high mileage.

Mounts are all OEM from the dealer, minus the rear one, it is aftermarket. I am taking it back to my mechanic so he could check it out again. But he said there probably not much he can do.

Any suggestions on what it could possibly be?

 

I know that the mounts shouldn't be fully tightened until the motor is "centered". The way I understand it is you loosen the mounts and let the engine center itself. This is with the weight of the engine on its mounts. I will ask my top tech on Monday about the exact procedure. Basically you loosen the mounts slightly, start the car, rev it a bit, put it in drive/reverse, then put it back in park and shut it off. Then tighten the mounts.

 

With that said new mounts will transmit more vibrations but it shouldn't vibrate as badly as your describing.

 

In addition, mount bolts should be torqued to spec. Only other thing that comes to mind is new mounts can sometimes have a break-in period, but that usually only comes into play when upgrading stiffness.


Who makes the rear mount? Either way his reasons dont really add up.

 

The OEM mounts use a vacuum system to emilinate vibrations. The only aftermarket mounts that we have heard of here don't use the vacuum and transmit a lot more vibration based on user feedback. However, their durability is believed to be better. If the rear mount used here is similar, it would make sense why you are feeling more since it is the mount closest to the cabin. Why didn't he use OEM all around?

 

Try neutrilizing mounts?

 

beekermartin: If you could get that info, that would be a huge help! I am going to take it elsewhere and have them do it.

RedRyder: The rear mount is apparently the same exact thing the dealership sells, its just not directly from them. So pretty much all OEM.

oo7spy: He was replacing my rack n pinion and told me I should replace the rear mount since it was already taken off to save on labor. He couldn't get a mount from the dealer same day.

acrdr: I am finding tons of info on that, so thanks!

AND THANKS EVERYONE, for all of the helpful info. I actually took it back to him with what you guys suggested and he fed me the same BS. Said he doubts loosening and tightening them would do anything. Told me to see if they soften up and then come back if they don't and he will try the procedure.

Well F that. I am going to ask around other shops. Id rather pay someone else to do it now, then wait around to see if it gets better.

 

For comparison, I recently had my motor mounts replaced by my Acura Tech. The engine idles as smooth as before, no degradation with the new OEM mounts.

 

Thanks, I am calling a local trusted Honda/Acura shop tomorrow to scheduling an appointment.

Also, what are the normal rpms for it to idle at? Normally its at 750 rpms and that is when it vibrates. In the morning when its cooler, its at about 1000 rpms and has noticeably less vibrations.

 

Mine are due too....and that's the route I'm taking. Car will be in for timing belt/water pump, and while they are in there.....

 

UPDATE: Called up a very reputable local Acura/Honda shop. Turns out the rear mount is not OEM or equivalent, it is indeed aftermarket.

Also, neutralizing the motor mounts on the RL is not required.

So the cheaper mount is the culprit. Kind of frustrating since I was under the impression that it was the same. Hopefully it softens up over time, im not gonna waste my resources replacing it.

MORAL OF THE STORY: Do not use aftermarket/cheap parts. Use OEM honda/acura packaged parts only.

 

Thanks for the update

 

That should not be the take away from this. Your vibrations are not due to a poor quality mount. They are due to a different mount design. Different is not inherently worse.

Honda mounts have terrible reliability. They break often enough to be considered a wear and tear item IMO. They will likely fail before your struts do. As I mentioned, the RL mounts use an air system to minimize vibrations. This system is prone to failure. The only aftermarket mounts that I have seen here are from XLR8 IIRC, and they do not utilize the air system. Because of this, they are more robust than the factory mounts, but as a consequence, they transmit more vibrations.

The take away here is that if the RL's smooth nature is important to you, then you should push for OEM mounts. If you are more concerned about having to replace the mounts again, then you should consider aftermarket options.

 

Thanks for rephrasing that. Well put!

Also, the mount is from worldpack, a wholesale dealer. It is the same hydraulic design, only cheaper. Not XLR8

 

Thanks for clarifying. Like I said, I don't think that option is known here. It may very well be a cheap, crappy mount like you said. I won't make any claims for a or against it.