Hello, I never really got a good response when trying to get info about replacing the motor mounts on a 1998 E430...
Well I finally replaced them they cost $80.00 a piece the part number was 202 240 29 17.. I drove the car up on some ramps then took the splash pan off
I could not visible tell that the mount was bad while installed except for the vibration and that some of the silicon had oozed out up onto the engine mount, obviously it turns brown after it burns.. The left mount was bad, I did read somewhere that the left ones go bad.. I would guess that when you floor it the left one is being pulled away from the frame with the torque from the engine... I had checked this by opening up the hood and turned he wheel as far left as possible, I gave it some gas and I could actually see the engine jump up...,
Anyway I took a floor jack and a piece of plywood to protect the oil pan , then I used a 13mm (I think) socket to loosen and remove the lower bolt, and a open end wrench for the top bolt after the were removed I started jacking real slow and I could see the engine rise up away from the mount , I pulled out the old mount,, It was beat. I positioned the mount, it will only go in way. I loosely installed the lower bolt then lowered the engine, everything was in place I applied some blue thread lock to the top one since I could tell some was there when I removed it. I am not sure about the torque on the lower one, I just torqued it enough where I thought it would not break... Don't pay the dealership the $500 bucks to do it, If you have tools and know how to change your own oil then you can definitely do this job..

This job should take about 30min excluding jacking up or using ramps for the car..

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Peter L. House
1998 Sport E430
Azure Blue
110,000k Miles

1987 Oldsmobile Cutlass Salon
V8 Bucket Seats
Factory Moon Roof