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BongC36 08-09-2002 10:07 AM

High engine temps SOLVED!
Ever since I got my C36 I had been concerned about the high engine temperatures that I normally experience, which ranged from 95C to 110C. Once, It even went up to more than 115C, when I met with heavy traffic afer a hard run.

While I have read many times on this and at other forums that it is normal for MB's to reach even 120C, I am not really comfortable seeing the needle so close to the red mark. I have experienced many warped heads and blown gaskets due to overheating on my other cars, and performance suffers as the temps go up.

I am sure that there are many here who share my preference for lower engine temps.

First thing I did was to install a manually-controlled relay that turns on my AUX FANS at stage 2 (high). This is my insurance policy since this relay is fed directly off a solid +12VDC source.

Next, changed the coolant with genuine MB stuff, mixed 55/45, and made sure my system holds pressure. It does, no problem.

I then installed a BEHR 71C thermostat. While this solved the high temps, I found that the engine took too long to reach even 80C, and that at speed the temp drops to 70C! This is bad since it accelerates engine wear and the fuel mixture is set to rich so I re-installed the old but functional BEHR 87C thermostat.

Still the temps were high. I next replaced the functional OEM viscous fan clutch with a SACHS tropical version. Sucess! Now temps ranges from 85-90C in traffic or freeway, motor feels more powerful, and I can relax knowing I am far away from the red zone.

This tropicalized unit has a lower lock-in setting than the standard clutch. Part number is 2100 006 243.


stephenson 08-09-2002 10:15 AM


Way cool on the tropical component ... many would likely benefit from this ... how would I go about checking for a tropical version on a W126? Is it shown in a dealer database somewhere?

BongC36 08-09-2002 10:25 AM

George, sorry but I dont know if the SACHS unit will fit your car. It fits on my 190E 2.6 (103 engine) and the C36 (104 engine). I'm sure our techs can help.

Part number is 104 200 01 22 and mfg code on the box is 2100 006 243. What I noticed was that whereas my OEM unit was still free-wheeling at an indicated 100C, this unit is locked up when I shut off the engine at 90C.

stephenson 08-09-2002 10:30 AM

Thanks, Bong ... I did not initially notice where you are located ... after having spent a few years in Philippines, I can certainly understand why a better viscous clutch would be applicable.

The physics on this sort of thing are pretty simple - I had heard of someone modifying the vclutch to lock up earlier by adjusting the bimetallic portions, but thought one actually designed for a hotter climate would be much better.

Where are you located?

BongC36 08-09-2002 10:34 AM

Am based at Subic, Olongapo City

stephenson 08-09-2002 11:33 AM

I have spent a lot of time there. Was a P-3 pilot based in and out of Cubi Point.

How is the economic situation? I saw some photos taken by a FedEx pilot friend and things looked very nice - economic growth of a good kind.

BongC36 08-09-2002 01:24 PM

George, pls check your mailbox

jsmith 08-16-2002 12:00 PM

Good stuff Bong! Anyone out there find a source for this part in the US yet? I don't know if this is easily ordered or not since the part number is not the xxx xxx xx xx format.

I had read before that there were tropicalized versions of cooling components in MB's. It was just a matter of time before someone from the tropics verified this. Now that global warming is producing these hot summers in the US, this information could be critical. We've had several 100F+ days this summer here in NJ and my car is keeping it's head above water with the help of the resistor mod. I agree that this is a much more elegant if not the correct solution...

jsmith 08-16-2002 04:12 PM

i just got a quote online for 104 200 01 22 $159! wow, it might be cheaper to import one from the philippines...

BongC36 08-17-2002 12:00 AM

I paid around US$ 105 for the SACHS tropical unit from an MB dealer here, and I must say it works like a charm on my C36. The temps stays between 85-95C all the time (traffic, high-speed, stop-and-go).

Engine feels stronger now, probably because my timing does not get retarded by the computer because of elevated temps. I used to see 100-115C all the time, and my timing was probably dialled way back to avoid detonation.

I wish everybody who is concerned about high temps will know about this clutch. It is an elegant solution since it keeps the engine (and me) coool without turning on the aux fans. Warm-up time is unaffected. I have shut off the engine many times when the gauge was around 80C and the fan was still free-wheeling. At gauge=90C the fan was locked so it is probably grabbing at around 85-90C. Stands to reason since the stock thermostat is set at 87C and I presume that SACHS developed this tropicalized clutch in conjunction with MB.

jsmith 08-17-2002 07:51 AM


i'm trying to keep this thread up to get more exposure. i'd like to get one of these for my m104 as i like your description of your car's temp characteristics. the resistor mod does keep things in check but temps can fluctuate depending on the resistance value you use. i am using a higher temp cut in than what most everyone else is using because it keeps my temps at 90C most times without the aux fans. however, in high temp situations it can fluctuate from 85C to 100C from the high speed fan cutting in and out. i think that with this fan clutch, the resistor mod will no longer be needed. here's a couple of items that might be of interest.

-there are 82C thermostats available which you may want to try. this won't affect your warmup as the 70C did and may even prevent the viscuous fan clutch from engaging all the time. i am thinking about trying one of these too next coolant change.

-doing a search on sachs viscous fan clutches, i saw complaints about their failure and overheating which resulted in warped heads in older BMW's. i guess that is why MB has the high speed aux fans as a failsafe.

Arthur Dalton 08-17-2002 09:37 AM

<<there are 82C thermostats available which you may want to try. this won't affect your warmup as the 70C did and may even prevent the viscuous fan clutch from engaging all the time. i am thinking about trying one of these too next coolant change. >>

I think the thermstat temp range is the most contributing factor..
Very hot here lately, so I stuck a 79C in there from another older Benz just for kicks and the aux has never come on once ..
[ and I have parelleled it to cut-in at 100c]

I'm sure the milage will go down as I can tell it is running richer
than w/87C Thermo, but they like them hot/lean for emmissions/milage, so maybe this is a good in-between...

Might even go with winter/summer thermos like we used to..
So, that 82 might be worth a try, as I find the 79 slightly low for my likeing..

BongC36 08-17-2002 01:10 PM


Yes I was also told by the dealer about the 82C thermostat. I had actually bought one already and was supposed to try that next but I am already satisfied with the way the current setup is working. I like the way my 104 responds when it is between 80-90C.

Clutch failure? Gee I hope not, although I still have the 2 aux fans operational. There was a time the Aux fans failed and my temp reached 120C!

The aux fan relay coils are fed from a fuse which also supplies power to other loads such as the windshiel washer heater. Apparently there was a ground, the fuse blew and my relays were dead, along with the fans! My insurance is an additional relay which I wired up to supply power in parallel to the existing circuit so that even if the relay coil fuse blew again, I will still have power to the fans.

Since the clutch, I haven't heard them come on yet except when activated by the high pressure sensor in the AC circuit.

BTW the OEM fan clutch in my C36 was also made by Sachs.

rainmaker 08-18-2002 02:17 AM

Would anyone here know if the fan and clutch would fit on a 500E?

JimF 08-18-2002 11:49 AM

Good work BongC36 . . .
check the Sachs website out:

Click the "ENGLISH" tab and fill in the car info, etc. to get started. It's not easist to navigate but with a litte work, you can get a part number for a replacement VFC for your car. But can't find a "technical manual" or pdf to see where it designed to cutin and cutout.

But if it's like Bong's part (lock up around 90C), that would be ideal.

Rainmaker my part number is 2100 013 031. Also the internal pn is MNT9K-C1. It fits a 119.070 engine for C140 cpe. But should be the same part for you. The MB pn is 119 200 00 22 but don't know if that's the Mercedes cross reference to the original part????

Can anybody find what the specs are on the clutch???

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