Specific Thermostat question - higher temp replacement 240D
 

Hi all.

Searched the forums and didn't find anything this specific. I've even called fastlane with no luck so probably no oem replacement. I'm doing a conversion on vehicle to vegoil, but that's not that important. Basically, the car runs cool, way cool. I think the thermo has failed. Would like to get a replacement that opens at higher than 80* C. No luck finding one...yet. I had to run this car forever with AC on just for it to hit 80 and the kit I'm installing will only switch over at that point, so I guess it is important.

I think the fan might be stuck too, but I will research that one too before I post. So to review, anyone found a replacement thermo rated higher than 80*C?

grazi.
-Tony (no I am not italian)

i would stick with the original thermostat, what is an idea is to restrict air flow across the radiatior to allow it to run hotter.

The cardboard idea works great but if the thermostat is stuck open it won't be the best solution because it will take a long time to get the engine up to temp.
A better idea is just change the thermostat, then if you are driving in sub zero temps use the cardboard.
If you are serious about needing a hotter thermostat the ones from a gasser would be an alternative, they come in 87 and I believe 93 degrees, for sake of lower emissions the factory raised the temps years ago. I stuck one in a 300D to see if the gauge was reading correctly and it worked fine, I removed it later and put a stock one in to replace one that was sticking open. This kind of failure is not uncommon.

hotter stat
 

Autozone also lists a stat at 195F for these cars. Not sure you would want to go much hotter than that. Cardboard would help the temps rise faster also.

Glenn

Just use a method to block the air coming in the radiator. Much easier to remove when it starts to run on the hot side.

Gasser thermo?
 

I guess my question would be, does it fit the diesel? I guess other than that they all basically work the same way. Like I mentioned in my original post, I think part of the problem is the fan seems to be always engaged which certainly doesn't help a cool running car and also, sort of defeats the purpose of cardboard since fan will be on anyhow.

thanks for the info so far though :)
-Tony

Cardboard will still restrict the air flow. Sort of like the big semis with the covers on their grill. I drove them before and it makes all the difference in the world in the winter.
I think the MBsare made to run near 80C. I don't think I would change it. Diesels as a whole run on lower temps. Heat will kill them.

80c = 176F
87.7= 190F
90.5=195F

I would run the 195 deg t-stat, my Cummins runs at 190F all the time, the Benz runs around 90C for the most part-a lot of people have stated here that SLIGHTLY warmer temps will help with fuel mileage slightly, but I wouldn't recommend above 105C. The problem with the cardboard is it will probably only help at highway speeds, I think little or no help in stop & go at low speeds.

Since the only time water is moved thru the radiator, with a properly operating thermostat, is when the t-stat thinks the water is too hot then blocking off the radiator seems silly to me. I have a 190 stat in my '77 300D for a year with no problems. I got it so the car would be warmer in the winter. I plan to do the same to my '83 soon. I got my stats from Advance Auto, had to order them though.

well yeah
 

it seems like that cardboard shouldnt work, but it does. i cant explain why though.

tom w

Just do it!
 

My car wouldn't even think about 80C and most of the time ran closer to 60 on cooler mornings. I replaced the stat. w/ the Behr 80C and now it runs steady at about 90. If that doesn't warm it up enough, then you can always add cardboard.

With my new oem stat, temp rests at 90
 

I have same problem with fan engaged all the time. I noticed when turning the engine by hand that I could hold the fan and it would not spin. So it is not "engaged" like i thought it was but rather there is a little to much friction and maybe can be fixed with grease or by loosening some bolts. I have yet to try to hold it with the engine running :0 Now ..

I had overcolling and changed the thermostat and it gets up to 80 pretty quick and rests at about 90. It did not look at temp but it was a Behr made in germany. I would say 10-15 minutes in 32*F . Probably like 5 minutes in the summer. So the 80* degree stat may work for you.