I've been noticing quite a bit of clunking noise in my car lately so I'm suspecting my motor mounts are bad or going bad (117k). I popped my hood, started my car, and watched the engine as I shifted from P to R to D and back to P. While shifting I can see the engine moving which seems like a motor mount problem.

My question is this. With the electric mount by the radiator in a 4AT, is there any movement expected while the car is idling/not moving? My understanding is that the RPMs are what cause the electric mount to stiffen so if the car is stationary is some amount of movement expected while shifting?

2002 GLE 4AT

 

A little bit of movement will be seen when you shift from park/neutral to reverse or drive. But it is a little, tiny bit. After the initial jolt of the transmission engaging, you shouldn't see any movement.

The real test is to put the car in drive, keep your foot on the brake and give it the gas as in floor it. The engine will rock maybe an inch if the mounts are good. If the engine jumps up like 4 inches, you have a bad mount. Also do this procedure with the transmission in reverse to check the other mount. The side of the engine that raises up has the bad mount on it.

If you live in the snowbelt, check the lower radiator support. If it has rusted out and allowed the engine cross member to drop, this would also allow the engine to move.

The mis-named electric motor mounts that are really hydraulic motor mounts change from soft to stiff at 1000 rpm. Some people advise you to unplug the motor mount because the electric motor that pumps the oil might short and cause damage to the ECU. If you do that, rev the engine over 1000 rpm to get the mount in stiff mode and then pull the plug.

 

There may be some movement but not clunking. The movement should not exceed 1", measured at the top of the chain cover. From my experience, clunking is often caused by the passenger-side mount wearing out it; usually, you can hear it on bumpy surfaces and when accelerating in turns. So check out this mount, I bet it's worn out.

Re. the front&rear mounts (these are the electronic mounts), inspect them for any damage to the rubber compound. In either case, I would disconnect and/or replace them immediately - this note https://drive.google.com/file/d/0B6O...1fNlF5QjQ/view explains why.

 

I appreciate both the responses. I'll have to see if I can rig up a ruler/camera combo by the chain cover and try giving gas with the brake applied to check the amount of movement.

I was aware of the IACV issue which I didn't care about since I have a 5.5 gen but I didn't know the auto mounts could cause the same problem. I've been debating replacing both torque mounts with the manual/ES bushing combo but I'm not sure how I feel about the added idle vibration. Plus I'd have to source some manual mounts from somewhere.

Whatever I end up doing I plan on replacing the transverse and transmission mount as well.

EDIT: Forgot to mention, Dennis, I'm in the Sacramento, CA area so I'm about as far from the snowbelt as I can get. My car was originally owned in NJ for it's first 1-2 years so it has had some snow/salt exposure though I've check the rad support in the past and it looks good. No rust from what I can tell.

 

You can always disconnect the electrical plug that goes on the front and the rear mounts, I heard the Energy Suspension mount are very stiff and you might have some tolerable vibration through the cabin of the car

 

I have one for sale if needed, the rubber on mine finally went and all the fluid came out, replaced with oem one and its as good as new. Everyone and their disconnecting the connector because of burnt ecu, that's non sense.

 

Thats the same thing i was thinking, a bunch of non sense that does not apply to the 5.5 gen with the 3.5 engine. Different engine, different ecu. Now it may happen on the 5th gen 3.0 motor ect. I have a bad rear mount now gonna replace it soon.

 

I am new to the forum so pardon the intrusion,


I purchased a front motor mount for my 2010 maxima and noticed that it appears to be larger in size. My question is due to my being a novice when it comes to cars is:
Being that it is a hydraulic mount, will I have to compress it prior to mounting?
It appears to be about 3 inches larger in height.
I would like to know before I take it back to the auto parts store.


Thank you.

 

You're going to want to ask in the 7th gen forum. This is the 5th gen forum (for 2003-2003 maximas). There's a thread for new people who have a question stickied at the top of the forum there.

 

more than likely you have the wrong mount for your car. and no...you cannot compress an engine mount.

 

Thank you everyone.