Specific Thermostat question - higher temp replacement 240D - PeachParts Mercedes-Benz Forum

DieselConvert · #1 12-07-2005, 02:14 PM

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)

#2 12-07-2005, 02:17 PM

Quote:

Originally Posted by DieselConvert

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.

dieseldiehard · #3 12-07-2005, 03:50 PM

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.

glenn1179 · #4 12-07-2005, 04:17 PM

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

Diesel Giant · #5 12-07-2005, 04:27 PM

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.

DieselConvert · #6 12-07-2005, 05:13 PM

Quote:

Originally Posted by dieseldiehard

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.

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

Hotdogseller · #7 12-07-2005, 06:56 PM

Quote:

Originally Posted by DieselConvert

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.

Hotdogseller · #8 12-07-2005, 07:00 PM

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

bullwinkle · #9 12-07-2005, 07:42 PM

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.

MB-Owner-in-ind · #10 12-07-2005, 08:42 PM

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.

t walgamuth · #11 12-07-2005, 11:13 PM

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

tom w

linguica · #12 12-07-2005, 11:30 PM

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.

biopete · #13 12-08-2005, 09:07 AM

Quote:

Originally Posted by DieselConvert

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

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.