Mercedes-Benz Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
600 Posts
Discussion Starter #1
Installed thermostat--leaked. Took out, installed with new o-ring--leaking. Repeated--leaking.

All I know is that it the water drips off of the bottom bolt. Do I need thread sealer for the bolts?

Do you see anything wrong with where the thermostat and housing attaches? Looks to be some gashes on the side, near the lip or face area?

300D 602
 

Attachments

·
Registered
'95 E300 DIESEL, '91 600SEL, '92 600SEL
Joined
·
17,388 Posts
Clean up the mating surfaces on the engine block side, and use a new o-ring and new thermostat housing.

Also be sure to align the thermostat properly. There should be a notch and/or small caged ball to allow the stat to pass small amounts of coolant.

And only use Behr or Wahler or genuine MB stats exclusively.
 

·
Registered
Joined
·
600 Posts
Discussion Starter #3
Yes, it's a Wahler with new o-ring. If you look at the second pic towards the bottom right, there are gashes. That doesn't look normal. I'm thinking of trying some high temp gasket sealer that comes in the red tubes. What do you think?
 

·
Registered
1968 gto (sold) , 91 volvo 740, 89 $300TE, 89 560SEC
Joined
·
432 Posts
I think i'd take a draw file, or a die grinder with a "cookie" and smooth out that mating surface. Get it to where its smooth, flat-- no hi's/low's. Might have to have a housing too.....
 

·
Registered
Joined
·
600 Posts
Discussion Starter #7
Well, I tried again.

I used a bastard file to smooth down both faces. Then I used a tiny amount of brake cleaner to clean the faces. Then I used Permatex Ultra Copper gasket sealer. Installed it and let it cure for 24 hours.

No leaks! Maybe this is just something you have to do on 200,000 plus mile cars.

I think the previous installation used gasket sealer and therefore left the surfaces uneven.
 

·
Cruise Control
'87 300TD/'90 300D/'94 Quattro/'89 Vanagon TDI/'01 EV Weekender VR6
Joined
·
52,233 Posts
I've been meaning to bring this up. I come from the VW world, where it's pretty routine to replace the waterpump AND housing at the same time. That doesn't appear to be as common with these engines. Having removed a couple of these housings now on engines with more than 200k, I've found that not only is the housing corroded, but the housing to block gaskets are also quite deteriorated. I've also seen the early style housings crack.

With that in mind, if you've got a 60X engine with lots of miles and a need to replace the waterpump, I strongly suggest you consider buying a new housing at the same time.
 
1 - 8 of 8 Posts
Top