Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help

Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

LinkBack Thread Tools Display Modes
Old 09-16-2003, 01:05 AM
Posts: n/a
1985 300SD thermostat housing leaking

Pulled the thermostat the other day, account I thought it stuck,
but it was just low on antifreeze. Put it back together and it was leaking. I didn't see any gasket, when I took it apart. So took it apart again and applied a little blue sealant. Its seems to have stopped the leak. Is that normal to apply a little sealant???? Or should I have used something else?????? Thanks in advance....
Reply With Quote
Old 09-16-2003, 01:20 AM
Mr Goodfahrt's Avatar
Registered User
Join Date: Sep 2003
Location: Maryland
Posts: 136
Talking I think there should be a gasket....

I have a 123, but I'm fairly sure there should be a gasket. They come with the thermostats but there are 2 kinds. One goes around the outside of the thermostat, and the other fits on one of the inner surfaces. You need either one or the other.

Blue Stuff, if it is silicone, is real bad for the cooling system according to some posters here. I'm a newbie, but I just did my first coolant flush. When I got my thermostat they gave me the wrong gasket the first time.
Mr Goodfahrt (pronounced FAIRT... means "good trip" in German)

1982 300D Turbo Pastel Gray (off-white) 200k+(?)
newbie but willing
Reply With Quote
Old 09-16-2003, 04:01 AM
vwbuge's Avatar
Registered User
Join Date: Sep 2001
Location: Johnstown, Pennsylvania
Posts: 2,101
When doing a job like that I always use a gasket and a little blue stuff for good measure.
'85 300SD (formerly california emissions)
'02 Jeep Grand Cherokee Limited
'04 VW Passat W8 (6spd manual) SOLD!!
'68/'69 Empi Imp body on '65 Beetle pan
'93 Ducati 900 SS
'79 Kawasaki KZ 650
'86 Kawasaki KX 250
'72 Triumph T100R
'70 Yamaha R5 Rat Bike
Reply With Quote
Old 09-16-2003, 11:05 AM
Join Date: Jul 2001
Location: Old Lyme, Connecticut
Posts: 3,596

I only use a sealant when the surfaces that form the joint are pitted or corroded and do not clean up with a fine abrasive. I still use a new gasket though and only count on the sealant to fill in the uneven surfaces under the gasket.

Pitting and other signs of corrosion are an indication of an incompatible sealant having been applied, or too infrequent changes of coolant. Most manufacturers select gasket materials to be compatible with the various base materials of parts, and the coolant chemistry to avoid typical corrosion problems. Arbitrarily changing these can increase the likelihood of a corrosion event significantly. In the case of the thermostat housing, I believe the gasket design is intended to isolate the galvanized steel thermostat support ring from the aluminum housing, as that is what was intended for the 1982 240D we have. Other models will be slightly different and newer ones have plastic housings or housing covers to further minimize the corrosion potential.

Good luck and I hope this helps, Jim
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)
Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 09:40 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page