gasket sealant confusion - PeachParts Mercedes-Benz Forum

msethk · #1 07-02-2007, 08:04 PM

i have searched and researched

for the last 4 or so hours and am really confused. I am installing a thermostat on a 1994 c280. i want to make sure to have everything i need before i start. I see many posts that call for loctite 5900 sealand or even 5970. i have also seen something called permatek "right stuff." I called the dealer and they brushed me away from the purchase of the mb brand sealand because it is $39 for a small tube and was referred to pep boys to find a permatek brand (nice, what an awesome salesperson... if i were his boss

i would have fired him

... there goes his comission..hehe) what should i use for the sealant

?

thanks

smharr4 · #2 07-03-2007, 01:41 AM

I don't think you need to use sealant when replacing a thermostat. I never have, and I've never seen evidence of old sealant on the water pump, and nothing is mentioned in the repair sheet (20-1100).

There's a black rubber o-ring seal that needs to be replaced, but one should come with the thermostat you shouldn't need to purchase anything extra.

Torque on the thermostat housing cover bolts is 9 Nm. Don't overtorque and snap the bolts, replacing that water pump is not trivial (did it this past weekend though, yay me).

mbdoc · #3 07-03-2007, 08:01 AM

Using any sealant on gaskets is a waste of money.

MOST MB applications that require sealant are metal to metal surfaces.

Mike Murrell · #4 07-03-2007, 01:11 PM

Quote:

Originally Posted by M.B.DOC

Using any sealant on gaskets is a waste of money.

Yep...and doing so will likely cause a leak as the gasket is all that was intended to be there to begin with. Make sure surface is clean, smooth and not gouged from using gasket removal tool.