FAQ: Am I having a motor mount failure? And how to replace:

Sir Sam · **Posted:** Sun Aug 28, 2011 1:25 am

So I figured this thread will be the first of some FAQ topics to add to a sort of advanced noob guide.(would that just be a guide?)

So that being said here is the concept for this thread. If you have had a motor mount failure please speak up, which side did you have fail, what was the failure mode(sound, vibration, clunks etc), and how you managed to replace it(if you get really ambitious made a little writeup with pictures and such).

That all being said, let me briefly summarize what I typically see with motor mounts:

They either fail internally and make noise, or the nuts that hold them in get a little loose and make some noise. Its cheap and free(and did I mention free) to try tightening the nuts, so thats a pretty good first thing to try. Now if they fail internally and make noise you can remove them and then once out if you shake them you can hear something rattle.

The motor mounts are the same left to right, but the pass side mount has a heat shield, this heat shield can be reused on your new mount, so if you order the drivers side mount(which is a bit cheaper) you can put the heat shield on the mount to save a few bucks.

racertracer · **Posted:** Sun Aug 28, 2011 2:12 am

MY crd had a noise on the passenger side that sounded like a thump when coming to a stop and when taking off from a full stop.

I still have the failed motor mount on a shelf in the garage and shaking it produces a rattle.

ATXKJ · **Posted:** Sun Aug 28, 2011 7:02 am

The noise will vary if your in neutral, drive, reverse
both of mine died - Drivers side rattled worse-

GDE has a good writeup on the passenger side changeout
http://www.keepandshare.com/doc/2444390/kj-crd-engine-mount-replacement-rev1-pdf-december-15-2010-9-20-am-1-4-meg?da=y

CATCRD · **Posted:** Sun Aug 28, 2011 9:26 am

Mine started making a rattling noise from the engine bay that would change a little between P-R-D, but the engine wouldn't jump or move noticeably. It was hard to pinpoint the noise above the sound of the running engine. I turned it off and wedged a board between the front crossmember and oil pan so I could pry and lift the engine while laying under it. I could feel a slight clicking in the passenger mount when shaking the engine like that, so I took the mount out (nuts were tight and it looked perfectly fine) and when I shook it I could hear loose parts inside it.

ChesterCRD · **Posted:** Sun Aug 28, 2011 4:23 pm

Mine started as an uncharacteristic rattle around 50K miles. It was about the same time we were all learning about the alternator decoupler, so I suspected this also. I used a listening tool (long screw driver against my ear) on various parts of the engine bay and engine and could hear the rattle best in the cross member beneath the engine. I took it to a garage I use for things I don't want to deal with and asked them to check the mounts. The day it was there, I could not hear the rattle all. They responded that the mounts were fine. The issue came and went and eventually became more pronounced around 80K. I was leaving work one day and I heard a sudden crunch...the engine bottoming onto the cross member.

I replaced both mounts a couple days later. It wasn't a bad job following the write-ups available on this site and I should have done it sooner. I need to get back under there and measure the gap between the cross member and oil pan. IIRC it was around 1/2 inch with the failed mounts and two inches after I changed the mounts but I figure it will settle some as they wear. This measurement might be an indicator for failed versus good mounts.

camo · **Posted:** Sun Aug 28, 2011 6:43 pm

mine sounded like I had a bunch of marbles loose inside the engine. Ones the libby reached operating temp, you would hear rattling at idle regardless of the gear the transmission was on. The classic check for vibration shifting gears between R-N-D didnt showed me anything neigther did a vidual check, I actually had to remove the mount and shake it to realize that the mount was source of the noise. once the passanger mount was replace the rattling was gone for good :-)r

grywlfbg · **Posted:** Tue Aug 30, 2011 2:39 pm

racertracer wrote:

MY crd had a noise on the passenger side that sounded like a thump when coming to a stop and when taking off from a full stop.

I still have the failed motor mount on a shelf in the garage and shaking it produces a rattle.

Hmm. My wife is complaining of something similar. She thinks it's the transmission but it doesn't sound like transmission to me. It doesn't make a thump noise, but you can feel a bump in the brake pedal when coming to a stop and when taking off from a full stop. Can't decide if it's u-joints or motor mount.

Is there a GDE write-up for the other side motor mount or is the procedure the same (without the turbo/CAC hose removal of course)?

thomas04 · **Joined:** Sun Feb 28, 2010 1:57 pm **Posts:** 129

This may or may not be a motor mount concern. I have a high pitched sound to my diesel purr when at idle or when starting the acceleration process. It is tough to hear unless you own a diesel. Is this an appropriate sound for a diesel or can it poossibly be a motor mount? Also, does anyone have pictures as to what the motor mounts may look like? I would be very interested in checking them and possibly tightening to see if this solves my high pitched rattle/purr noise. Thanks.

Peace.

CRD Joe · **Posted:** Sat Oct 22, 2011 10:36 am

Should you replace them both at the same time. Im not even sure I need them.

76,000 miles.

CRD Joe · **Posted:** Sat Oct 22, 2011 10:38 am

Well bugger, there are two front mounts (left and right) front mount brackets and a rear mount!

Replacing them all is bucks.

dieseldoesit · **Posted:** Sat Oct 22, 2011 11:06 am

Since there isn't much to disassemble when changing them out, I would only replace the one that is bad. I replaced both front mounts of mine, and only one was bad. I wish I would have saved the money and replaced only the bad one, though now I have a spare one on hand... taking up space...

If I remember correctly, it was the passenger side that went out, which is supposed to be the more likely situation.

thompsonCRD · **Posted:** Mon Oct 24, 2011 8:43 am

Twice in about 10 days I heard a noise that I describe as grinding, close to (but not quite as bad) as trying to shift a manual transmission into gear without the clutch fully engaged.

Both times happened under similar conditions...
Start Jeep up in morning, drive 15-20min to a destination, stop for 1-2 hour, start Jeep up again, pull out of parking lot, noise occurs for about 2-3 seconds and disappears.

No other symptoms that I could notice (ie jerking, bumping, thuds, etc.)

Does this sound like motor mounts failing? I couldn't really tell where the noise came from, by the time I got the radio turned off it was gone.

Any other ideas welcome.

FAQ: Am I having a motor mount failure? And how to replace:

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