R129 1997 SL500 - engine mounts

[simonshearer]

I would appreciate advice from anyone that has changed the engine mounts on a 1995-2001 SL500. I imagine it is all the same for this version.

I have the mounts ready to install, but I cannot find an SL-specific DIY in any search, or in the DIY section.

I need to know the various steps to get started, especially how to reach the upper bolt head to remove it.

Thanks.

[simonshearer]

This is not a DIY for anyone lacking confidence and mechanical aptitude! The dealer wanted $1,010 for the job (including the parts) and now I understand why. Having said that I am pleased I tackled it and in combination with an unrelated steering damper replacement, and hood insulation pad replacement at the same time, the ride is very very smooth and quiet. The car purrs at idle.

You'll see from the photo's that the mounts were completely shot.

I read up as many accounts of this DIY and found a post on (that other forum) that was quite (but not totally) helpful - at least it was the same job on a 1997 SL, same as mine.

Cold car - don't burn yourself!

I did it in my garage on ramps - there's not a lot of room under an SL even on ramps. Don't forget to chock the back wheels and engage the parking brake.

1. I started with the passenger side, and removed the two lower bolts, which were easy to get out. I did that because I needed to raise the engine on that side in order to get access to the upper bolt at the top of the mount; my hands are simply too big.

2. Then I removed the fan shroud by unclipping it at the top and rotating it towards the driver's side; then I just hung it over the fan. Caution: in your haste to complete the job, don't forget the lowly fan shroud, hanging on the fan.

3. The only other thing I removed was the oil pressure sender device at the bottom of the oil filter assembly. It was helpful in order to remove the old mount. Of course be prepared for a lot of oil to drain out of the oil filter assembly.

4. I took off the heat shield (3x small 8mm screws) but as it turns out it wasn't necessary once the jack was full height.

5. I used a 6-ton jack with a short 2x4 under the oil pan, and for precaution used jack stands elevated high under the side jack points just in case the jack under the oil pan slipped out - you'll need to get it up pretty high to remove the old mounts, and then even higher to get the new ones in - safety first!

6. Once the passenger side of the engine was elevated, I was able to get a 17mm ratchet wrench onto the bolt at the top of the mount - not easy to get it started but it'll come. Once that was removed, the metal mount cover could be removed. The cover has a slot in it into which the top of the mount fits (you can see the small nib at the top of the mount in the photo's).

7. Now the mount was very loose and I had to adjust the jack again to remove it out towards the back and down, passing by the oil filter assembly. The new mount would not go back in the same canal without elevating the jack a lot more (see the height difference in the photo).

8. With the new mount finally in place, I loosely located the two bottom bolts, just to get the threads started (it is important to keep them loose in order to get the upper bolt threads started (later).

9. Install the metal cover over the top of the new mount making sure the slot accepts the casting nib at the top of the mount. I lined it up by feeling for the threads below in the hole. Now it is time to slowly lower the engine back down so that the notch in the engine carrier fits down over the nib at the top of the new mount (and the threads of the bolt and mount line up). I lowered it until I was able to wiggle the mount enough to line up the bolt and get it started (about 8mm from home). I was able to finger-tighten the top bolt and that was enough.

10. After lowering the engine back down so the engine carrier rested fully on the new mount, I torqued the upper bolt (55Nm) and the two lower bolts (25Nm).

11. Lastly (for the passenger side), I reinstalled the oil pressure sending unit and tightened it (17mm wrench); and reinstalled the wiring connector.

I was pleased by my efforts to that point but the driver's side was somewhat more challenging.

12. I repeated #1 above for the driver's side old mount bolts.

13. I did not repeat #4, and left the heat shield in place.

14. I repeated #5, and as I started to elevate the engine on the driver's side I noticed that the rubber tube connected to the bottom of the power steering reservoir was being stretched. I lowered the engine again and then started what became a very messy job of draining the PS reservoir, and removing the connecting tube (and tucked it in behind the ABS tubing to stop it dripping over me all the time!).

15. So now the engine on the driver's side could be elevated and #6 above can be repeated. The metal cover off, the old mount came out and down to the front after pushing some A/C hoses out of the way. To get the new one in again, I had to raise the engine more, but it did finally slip in there, the same way the old one came out.

16. Repeated #8, #9, and #10 above.

17. I reconnected the PS tube to the bottom of the PS reservoir, and carefully topped up the fluid to the 20 degree C mark (not the upper mark - for a hot engine).

18. I reinstalled the fan shroud!

I make it sound easy. I left out all the cursing and getting covered in various fluids. On a 1-5 level with 5 being toughest, this was a 4+.

The steering damper was very easy.

The hood pad was very time consuming and made my arms very sore but wow what a big difference; absolutely looks like I have a brand new car!

Hope these directions help the next person...

[ctaylor738]

Nice wrench!