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So, lately I’ve been hearing clunks from the engine front area when I backed out of my inclined drive way at an angle (right rear tire on the road while the other 3 are still on the driveway). I also hear the same clunks on the uneven surface and when I slowly turned the car at slow speed.
There are 3 possible root causes to this, front strut mounts, sway bar links/bushings, or engine mounts. I first looked at the sway bar links, ball joints, tie rods, and LCA bushings. They didn't budge and they looked great visually.
I then looked at the strut mounts. They are Moogs but it was 60K miles old. I was almost sure that they go bad again. To my surprised both sides looked brand new when I opened it. The rubber mounts were in great condition and so were the bearings. I then cleaned the strut assembly components and regressed. Although the struts are still rebounding with decent speed and no leak, they are getting old by now since I replaced them new about 60K ago. They are KYB GR2 matched with Tein H Tech.
So, put it back together, torqued it good and the clunks still there. I then moved to Engine mounts. A couple months ago, I inspected the engine mounts when I refreshed my tranny and both sides looked decent with no cracks (at least that's what I thought...). Well it turned out that the passenger side was completely shot (picture to follow). I stuffed a solid rubber plate inside the broken mount for a temporary fix and the clunks were much much softer now. I still have plenty of engine movement when I power brake the engine though.
OEM engine mounts were pretty expensive and I wonder about the poly mounts. Unfortunately, we don't have poly mounts for the driver and passenger side mounts, only the front and rear mounts. So with this in mind, I'm going to experiment filling the gap on those mounts with polyurethane. I bought a DIY liquid polyurethane motor mount kit from suspension.com (https://www.suspension.com/blog/do-i...cement-inserts) along with brand new aftermarket passenger and driver side mounts (Anchor brand from Rockauto) and I'm planning to fill these as well as the front and rear mounts, which still look great, with this liquid poly. The kit is about 400 ml of liquid poly and I got the 80A durometer, which should be plenty stiff for daily driver.
So the next step is to figure out how much liquid poly each mount needs. To do this, I sealed up one side of each mounts with duct tape and headlight rubber sealer I have laying around and filled the void/gap with pre-measured water.
Both passenger and driver side mounts take roughly the same amount of 80ml of water to seal the gap/void. I have a feeling that it might take less than 80ml of liquid poly since its got more viscosity than water thus it would not fill all the nook and crannies. The front and rear mounts have only "half moon shape" of gap so it should take less than 80ml of liquid as well. Overall, 400 ml of liquid poly should be enough for all 4 mounts.
I decided not to do polyurehane filler for now. I was doing research on this and I think the engine torque brace/dampener might do a better job to limit the engine movement and make the rubber mount last longer. Having stiffer mounts create more stress on the chassis mount area and the OE bracket is pretty thin already. I may regret this do this but I'm going to try Engine Torque Dampener first.
Driver side mount is also cracking as well.
The rubber was getting pretty soft and mushy as well, I can just wiggle it with ease. The new ones are stiffer for sure but since these are cheaper aftermarket, who knows how long it would last. One problem during the installation, the threads are covered with paint, so I had to chase it with die set. I also cross threaded the top nut on the passenger mount. I ended up drilling it and putting M12x1.75 thread on them.
This is the stuff to use pick either one for stiffness you desire.
I have a screen shot of the urethane from the website. and the maxima org discussion on this. we all used this.
Underlined in red .
i used the 60 A myself ,the small container did two mounts . with some left over.
My mount's looked like yours, and i just drilled a bunch of holes,
In the stock mount rubber to get a good grab with the urethane
The poly came in the mail today. I was going to save this for later use but really couldn’t resist myself to do something with it. I cleaned the old OE mounts, scrapped more rubber out so get more poly in there. I used the left over to make giant washers, perhaps I can use this for my M3 rear trailing arm.
I installed ES solid poly motor mounts nearly 10 yrs ago and the rear ES motor mount appears to have failed cracked or dry rotted...Just got the new ES solid mounts in the mail this past weekend...Getting ready to do this, upper oil pan half moon seals, etc...and I'm good for along time again. Oh yeah nice job on the poly you poured/filled the mounts with!
With new engine mounts the engine throttle respond is better, the torque steer is also less. This makes me wonder if putting engine torque link/brace similar to NMP Engineering one would make it even better.
The front and rear engine mounts looks decent but the rubber feel old, I wonder if I should just get poly mounts or fill the old ones with liquid poly.
I just removed my ES motor mounts that have been in service for 10+ years and the rear was elongated about 2"...I installed the new motors mounts into the M/T MM frames, and actually installed the rear one incorrectly (offset should be on passenger side) so I had to press the mount out and I used an A/T MM frame (which is bigger) as a backup and pressed the ES MM out using a large socket and a floor jack against the bottom of my D21 chassis frame...I then soaped up the ES MM to install it correctly! It went in 75% of the way and then I back it up with the A/T MM frame and a large socket to press it 100% into the M/T MM Frame...Damn I need a press but a jack or a vehicle has the weight to press in anything!
great thread ! afwully intimidating tho! i am on original mounts im sure im at 240k today.... more than ever i feel a delay in throttle response and wonder if its old shEET mounts.
thanks for the detailed info Genisis and Krismax on all the products/process and poly stuff
This is the rear mount that was worn and created a slight buzzing vibration in the floor...But it eventually wore the bushing bore into a elongated bore! This fwd mount exhibited very little wear...
I accidentally transferred my iPhone pictures to my PC and found these ES motor mount pictures I took during the recent Upper oil pan moon seal, and motor mount operation I just performed...They lasted about 10 years before I noticed these wear!
08-16-2018, 09:19 PM
