300SE M103 motor mounts.

[Jorn]

I have to replace the motor mounts of my 1990 300SE, they are shot. I've read somewhere in the past that some owners replaced them with mounts designed for the 300SD, is this correct and would this be a simple bolt on?

Both Mercedes mounts would cost me $240.- and Lemforder doesn't seem to make them for the 300SE/SEL, so I'm looking for alternatives to hopefully save some money.

[Hit Man X]

W126 300SD mounts will 100% not bolt up. 350SDL may, order some and try and let us know how they hold up. They are quite a bit less expensive than the M103 units, maybe the rubber is stiffer and more durable for the heat the turbocharger outputs. OEM M103 ones seem to last around five years for me on average. The heat output from the exhaust manifolds kills the passenger side fast.

OEM work great and are probably your best bet.

Replace idler arm bushing while in there as well as the trans mount.

[Jorn]

Originally Posted by Hit Man X

W126 300SD mounts will 100% not bolt up. 350SDL may, order some and try and let us know how they hold up. They are quite a bit less expensive than the M103 units, maybe the rubber is stiffer and more durable for the heat the turbocharger outputs. OEM M103 ones seem to last around five years for me on average. The heat output from the exhaust manifolds kills the passenger side fast.

OEM work great and are probably your best bet.

Replace idler arm bushing while in there as well as the trans mount.

Will give them a try and will go OEM, will order them both and if it isn't a fit I just return them. I let you know my findings.

I have a new idler arm bushing laying around ready to be installed, when I have to lift the engine to install the motor mounts it's a good time to do so.

There isn't a heat shield installed with the current psg mount, is there supposed to be one?

[Hit Man X]

You MAY have to remove the exhaust to do idler arm. I never tried it with just motor lifted.

Yes, factory had heat shield.

[ChrisArnt]

I think instead of trying to put the diesel mounts on it you should put good quality ones for your car. I'm guessing that you think the diesel ones would last longer.

I doubt you'll be happy with the results even if they do fit.
The diesel motor moves around more than the gasser and the mounts are probably made to accommodate that.

[Jorn]

Originally Posted by Hit Man X

You MAY have to remove the exhaust to do idler arm. I never tried it with just motor lifted.

Yes, factory had heat shield.

Not looking forward to remove the exhaust, I've never had a good experience with unbolting one.

The previous owner or his mechanic must have been such a lazy bump, every protective cover or shield was/is missing on my car: fuel pump/filter cover, distributor cap cover, even the protective cover for the vacuum pump in the boot and now the heat shields...

[Ferdman]

Jorn, recommend buying genuine MB engine mounts. Replacing engine mounts isn't a DIY job you want to be doing routinely.

[Jorn]

Originally Posted by Ferdman

Jorn, recommend buying genuine MB engine mounts. Replacing engine mounts isn't a DIY job you want to be doing routinely.

I will take your advise, tnx.

[Mike D]

Originally Posted by Jorn

The previous owner or his mechanic must have been such a lazy bump, every protective cover or shield was/is missing on my car: fuel pump/filter cover, distributor cap cover, even the protective cover for the vacuum pump in the boot and now the heat shields...

Yup, reminds me of the old adage. "The difference between a mechanic and a technician is, a mechanic replaces, repairs, renews ALL the parts, a technician doesn't need all those "extra" bits".

[Mike Murrell]

For a 124, but should be similar for a 126

[Jorn]

Finally got some time to replace both motor mounts, it wasn't a hard job. The previous owner installed a Febi (psg) and a nameless brand on the drivers side. And the exhaust isn't resting anymore on the Idler Arm Bushing, not sure if that did any damage to the exhaust.

Replaced them with Mercedes mounts, not cheap.

Both the engine shocks are done and I ordered new ones and will install them hopefully this week. And next week I hopefully have time to do the head gasket.

Pasenger side


Drivers side

[Mike D]

Hmm, I'm guessing, due to the banana in the second picture, you are taking the expression "grease monkey" a bit too literal.