Quick question, relating to the "cooling system issues" thread. I'm posting this in a new thread 'cause I need a quick answer, if at all possible.

Is there anything special I need to know regarding changing out the thermostat, or is it straightforward (i.e. undo the bolts, remove, replace, put new gasket in, put new bolts in)? I"ve done a thermostat replacement before, but not on an M-B...if memory serves, the housing's pretty high up, but is attached to the lower radiator hose. How wrong am I there?

I ask 'cause I'm letting a friend borrow my Haynes manual, and I need to do the job tomorrow.

Thanks! And yes, this is for my '85 300D.

__________________
2001 VW Jetta TDI, 5 speed, daily driver
1991 Ford F-350, work in progress
1984 Ford F-250 4x4, 6.9l turbo diesel, 5 speed manual
Previous oilburners: 1980 IH Scout, 1984 E-350, 1985 M-B 300D, 1979 M-B 300SD, 1983 M-B 300D
Spark-free since 1999

Dear the Warden:

You only need to remove the three bolts holding the thermostat housing, then pull out the old thermostat and the rubber seal. Stick the new rubber seal around the new thermostat and put it in the thermostat housing. Be sure that the "spring" portion of the new thermostat points toward the engine, and that the arrow imprinted on the new thermostat points up vertically.

That's all!

Best regards,

Eric

Thanks, Eric.

Is there a gasket on the housing mating surface in addition to the O-ring, or is it just the O-ring? I ask 'cause Fastlane lists a gasket for the housing...

Thanks again

Dear the Warden:

I actually replaced the thermostats on 2 different 300SD. On one of them, I simply used a toothbrush to "polish" the mating surfaces and put in the new thermostat with the O-ring. There has been no leak at all.

On the other 300SD, I just applied some Permatex sealant (for water pump/thermostat) on the mating surfaces, even though I believed that it would not leak without that Permatex sealant at all. The O-ring for the thermostat should be enough to prevent any leakage. You can buy that Permatex sealant at Kragens or Autozone for about $2.5, which is plenty enough for many uses.

BTW, if you want to save some money when ordering from Fastlane or any other online store, just get the "thermostat without seal" for $12 and a separate O-ring for $1 instead of the complete Behr thermostat set (thermostat + O-ring) for $21. The "thermostat without seal" is made in France (by Caloric or something like that), and it even looks more solid and better built than the Behr one. I ordered 2 such thermostats (French ones) and they've worked perfectly so far.

Hope this helps.

Best regards,

Eric

P.S. J'aime la France et sa langue .

Thanks again! On re-reviewing Fastlane's listing, the gasket I was looking at is for the connection between the housing and the cylinder head itself.

Unforutantely, I need to do this tomorrow, so I'll have to get the Behr thermostat from probably the dealer... *shudders* Good thing I don't have a clutch; it'd be a trick trying to drive it with only one arm after paying the dealer!

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Thanks Greg

Almost done with finals...yay!!

PS. If I interpret your question correctly.... the answer is no, you do not need the gasket to the block... the thermostat can be changed, and it looks like the rubber is the only 'gasket' you need... the housing to head is different.. and not normally needed to change out the thermo.....

the xray view...

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For the record, I'm up this late 'cause I'm working on a take-home final (that was technically due 2 days ago; fortunately this instructor allowed me a reprieve; as to why I'm late getting everything done, it's a long story and not entirely my fault), not 'cause I'm in a state of near-panic regarding the car. I'm over here at the moment to allow myself a few minutes' distraction from the paper (actually, series of papers) that I'm working on, to keep myself from going completely nuts.

Do they have rehab centers for ' procrastinators' ? I guess no one would ever show up at their doors.... LOL

*lol* I will admit to being very bad when it comes to procrastination, but this one really wasn't all my fault...one of my other instructors had family problems that led to him not reviewing something with me on a large research paper until a week before the paper was due (and this review was required by him and needed to proceed with the paper), and while he was a little bit lenient on the due date for that reason, that pushed everything back to the point that between playing catch-up and working at the fundraiser that I mentioned in the other thread, I've been working my tail off for the last 3 weeks straight...I'm looking at the coolant flush I'll be doing tomorrow as a break *lol*

Just be sure when you head north that the person driving is well rested... Do you still have the same girlfriend you stopped by here with ?

We do have some wild , dangerous, extreme weather down here.

Actually, I'm heading south. My dad lives in the Mojave Desert, which gets as cold in the winter as it gets hot in the summer. And, amazingly enough, Robin hasn't killed me yet She loves the car as much now as she did when the two of us went out there to pick the car up and drive back (with the detour, thank you again )...although she's looking forward to NOT going back to Texas for some reason (not sure if it was the heat or the torrential downpour we ran into on the 10 west of San Antonio)... *shrug*

p.s. one more baby-paper, and I'm done! Hopefully within the next half hour... *fingers crossed*