Motor Mounts 1988 560sel - PeachParts Mercedes-Benz Forum

NickMendoza · #1 07-24-2003, 03:44 AM

I saw the engine lift about 3 to 5 inches in rev. The pass. motor mount is gone. I will replace them both. The car shakes a lot in park and during idle. Hard shifting from Part to Drive or R is also a problem.

1. Do I also replace the trans mount?

2. I have an exhaust leak. I smell exhaust after driving a while. I comes into the cabin without having the blower on. Has anyone had this problem? I have tried to find the leak with a hose and with my fingers. No luck. With all the movement, the exhaust system was put under a lot of stress.
Helllllllllp.

3. Are there other items worthy of replacement while I am down there?

4. Are there any rec. on exhaust points to look at for support that could have been damaged with the movement.

Thank you

Nick

joe p · #2 07-24-2003, 08:31 AM

Do the tranny mount as well as check the shifter bushings.

Are you sure the valve covers aren't leaking on the manifolds giving you the smell? (this is more common than the exhaust leak)

I'd give the oil level sensor a glance as well for leaking by the o-ring.

Joe

#3 07-24-2003, 09:12 AM

My 1988 560sel had the smell of burning oil with a wisp of white smoke coming from the passenger side of the engine. Oil was leaking on to the back of the exhaust manifold from the valve cover. Changed the gasket 3 times in 2 years trying to solve problem to no avail. Oil burning smell was just enough to smell in the cabin and when you pulled up at a stop light you saw the wiffs of white smoke coming from under the hood - nothing major - just enough to aggrevate. Turned out to be a warped valve cover. Took it off and sent it to a machine shop where they ground it level - re- installed - problem solved - going on 6 months now. Hope this helps.

Thomaspin · #4 07-24-2003, 10:55 AM

Recommended torque on the valve cover bolts in the M116/117 V8 engines with new crush washers is only 3 Nm - very little. Quite different from the diesels. Using old washers and a hardened old valve cover gasket probably increases chances of warping and/or leaking.

It's also very easy to have the gasket slip and not mate properly with the base of the cover (bitter experience speaking) so it makes sense to check the rubber seal all around with a bright flashlight before torquing down.

You can check valve cover warping by placing it on a really flat surface - a sheet of glass should work well.

mbtjc · #5 07-24-2003, 12:06 PM

I also replaced the engine shocks (right next to the mounts) while I was down there. Although not related, while you're into rubber mounts, you may want to look into rear subframe bushings.

NickMendoza · #6 07-26-2003, 06:32 AM

Thank you to all who have helped.

The motor mounts were split! Now I know why the engine would shake during idle. The engine lifted about 2 inches with the one new mount.

The two other small bolts were a pain. People next door went to eat and came back. I was under the car the entire time.

I will do the other side (drivers side) today. Should I loosen the pass. mount in order not to damage the new mount?

Should I take apart the linkage in order to access the drivers side?

Has anyone used blue locktite on the bolts?

I went to Pep Boys to buy the smaller allen. I cut it to about two inches. I then put the cut allen in to the bolt. Holding the top of the allen with my index finger - I turned the allen with a small combination wrench. It was the only way to turn it without having to fit it many times.

Thank you

Nick Mendoza

MikeTangas · #7 08-03-2003, 02:47 AM

As for the exhaust smell/leak, also check the exhaust manifold gaskets. Do you have a little ticking on cold start-up, that goes away once the engine is warm? If so, sounds like exhaust manifold gaskets. Word of caution, it is possible to installed the gaskets 180* out. This is most likely on #3 and #6 exhaust ports I believe. The last hack to work on my 560 (before my ownership) did just that. The gaskets do seal when installed 180* out, but quickly burn through. Worth a check.