OM651.924 (S212) 2.2 Wet or Dry Assembly Water Pump?

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New Member
Nov 2, 2023
E220 S212
Just refitting water pump and noticed the old seal had what looks like signs of blue hylomar between old seal and cylinder head. Have done a search and can't find the answer, so can't determine if it should be wet assembled or simply fitted "dry".

If it is best to wet assemble this part, I assume blue hylomar would be the recommended sealant here.

Anyone know for certain what Mercedes advise or whether it is advisable to wet assemble in this case?

Not sure if wet assembly would be detrimental or not in this case.

Also, what is torque figure for bolts?
Just to answer my own question to close this TQ out for future reference. Merc main dealer technical advice is to always dry assemble this joint (no sealant), so whomever did the job before (was a main dealer), did it not in accordance with published procedures.

Torque figure is 20Nm.
I fitted my genuine MB water pump dry, just made sure everything was clean and all the bolts were torqued up to spec.
So its ok for him , he wont have to change it when it goes next time i use sealant on all joints for extra insurance .. But it is up to you .
Good point and sensible advice as long as the addition of the Sealant (Insert your Favourite Bran here) doesn't go over the top! :(

Many folk overdo the application by adding far too much, I was always taught to just add a Smear of Clean Engine Oil to what are considered "Dry Joints" just enough to "Wet the Gasket" It allows the Gasket to "Bed in" on the application of the Torque Procedure, (Normally three white knuckles) :rolleyes:;)
See my second post 3rd May.

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