Nightmare locating thermostat, drain plug - PeachParts Mercedes-Benz Forum

braverichard · #1 08-16-2004, 11:01 PM

OK... The pictures included in the MBUSA Service Manual CDs for the location of the engine block coolant drain plug as well as that of the thermostat aren't clear enough to me.

Could someone kindly show me pics of:
1) The thermostat - an arrow pointing towards it in a pic of the engine would be great.

2) The engine block coolant drain plug as seen from either the top of the engine or under it. Again, a picture with an arrow pointing at it clearly would make it much easier for me to understand.

You can either post 'em here or send 'em to braverichard@hotmail.com

Sorry if these are elementary questions, but I'm pretty good at cars - driving them that is. I'm a Computer Systems Analyst and I've never worked on cars. I'm just learning to do so. At least trying to.

Thanks guys.

PS: The car is the 1984 300SD.

phantoms · #2 08-16-2004, 11:25 PM

Can't take any pictures for you right now as it's dark out. The thermostat is under the thermostat housing. Grab the top radiator hose. Follow it away from the radiator. The aluminum housing it's clamped onto is the thermostat housing.

As for the block plug, I believe it's either a 17mm or 19mm plug in the right side of the block, a little foward and up from the back of the starter. You can usually see it (if you know what you're looking for) through the wheelwell.

braverichard · #3 08-17-2004, 01:44 PM

Thanks for the tips. I found the thermostat and took it out.

I'll do the block drain plug stuff tomorrow. I'd still appreciate it if you could take a picture of that drain plug for me. Thanks for your help.

RockinWagin · #4 08-17-2004, 02:19 PM

What problem are you having? I just recently fought (and won) the overheating battle on my 84SD.

braverichard · #5 08-19-2004, 07:37 PM

Is the engine block coolant drain plug the huge plug with an electrical connection plugged into it? I noticed I have to remove that connection in order to fully get to it. And it is huge! Is that it?

The problem I am having with my '84 300SD is that it is overheating. When I drive it on the highway at 70mph for about 15 minutes or even less, the temperature gauge goes to 100 C. Then a few minutes later it can go to 110C and stay there. I haven't noticed any decrease in engine performance, and neither have I smelled coolant burning, but I consulted a man well experienced with Mercedes-Benzes and he told me that the engine was running too hot (just like I was thinking). So now I'm in the process of flushing out the entire cooling system, replacing the thermostat, seal and housing gasket.

What suggestions do you have for me? I read several pages of search results here and now all the plans I have come from my research results.

#6 08-20-2004, 12:01 AM

The engine drain plug is a much smaller plus to the right of the engine block heater, if I remeber right, it's going to be a 17mm bolt...

braverichard · #7 08-21-2004, 04:20 PM

Thanks all for your help. Found both items: thermostat and engine block coolant drain plug. Not like my problems were solved though.

Thread continued here: Overheating '84 300SD

skaa · #8 08-21-2004, 09:53 PM

Braverichard,
I was up under my '82 300SD today, and snapped this photo for future reference on this thread. The drain bolt is right behind the starter, (something I never knew, so THANKS!). Good luck with your problems.

SteveKaa
-------------------------------------------------------------------------------------

1982 300SD 337k miles

phantoms · #9 08-21-2004, 11:37 PM

skaa, you did a good job of getting that picture. I tried a few times with no success.

braverichard · #10 08-22-2004, 02:06 PM

SteveKaa, that was indeed a great picture. Very clear. If I had that in the beginning the whole process would have been a whole lot easier for me.

skaa · #11 08-22-2004, 08:59 PM

Braverichard and Phantoms,
Happy to help. This forum has saved my butt several times!
SteveKaa

-------------------------------------------------------------

1982 300SD 337k miles