Tricks to get get your m103 running cooler
 

there are mods and different parts I have heard of for a w124 chassis with M103 (mine is a 1989 300TE) but am not familiar with or don't know how to do them and I was hoping I could get some more information on.

The first one is about a Viscous Fan Clutch that is available for extreme climates that kicks the fan in at a lower temperature.

also there is this
I was wondering if someone could detail this for me a bit better, how is it normally set up, and how does using the low fan sensor on the drier get you high fan instead of low....... also how would you wire a cabin switch.

I know there is also supposed to be a resister mod, and I think there is a guy that makes some type of plug in to make your car run cooler.


If anyone can expand on any of these ideas or can add other tips or tricks please do so.

I assume you could easily throw a relay in and connect the low speed fan sensor to the coil and then run 12V to one contact and a jumper wire in parallel to the cooling fan.

<<I was wondering if someone could detail this for me a bit better, how is it normally set up, and how does using the low fan sensor on the drier get you high fan instead of low....... also how would you wire a cabin switch.

>>

You can easily get high fan instead of low for a/c by using the existing low fan circuit fuses. relay , and wiring, with these changes.
Low fan uses the R15 Resistor , so you disconnect that resistors feed wire [ the terminal with the single wire] and use that feed for a 30 Amp relay coil feed. [ Radio Shack has a nice one for less than $6] . Then ground the other side of coil.
The contacts set of relay will then be fed fused 12V from a good bat. source and the other side goes to the R15 terminal with the 2 wires on it.
That eliminate the R15 low fan resistor and you will now have a high fan speed when a/c calls for aux fan. B/C you are still using the stock low fan relay and sensor circuit, you do not have to do any changes on that part of the sensor circuit. You are simply jumping/eliminating R15.

Some try and just jumper R15, but that circuit has too small of wiring to run a high fans current demand and they will burn up..that is why we use a seperate 30A relay.

The cabin sw is simply put a toggle in the cabin and run a 2 wire zip cord [ lamp cord is fine] and hook each end to the pigtail connectors at the pressure sw . That gives you manual control of fans w/o upsetting the stock circuits..all will still work as factory, but you will then be able to Over-ride the stock fans activation manually...great for towing or traffic jams,etc.
That should be done regardless of a/c modifications, just to have a manual access to fans..very handy when needed..eliminates the old " Turn the heater on " in high thermal conditions when things get creepy....:)
You can aslo change the coolant sensor by bridging it w/resistor to lower the cut-in spec, but if you have a cabin sw , you can do that before it gets up that high, and if you are using a/c , the high fan will already be On with the relay mod anyway.......

Contact Jim Forgione on this forum. He sells a simple resistor assembly that plugs into the temp sensor. I had him custom make a 88C sensor for my 300CE. It cuts in at 88C and out at 82C. Perfect for here in the Desert.
Anziani

'93 300CE 172K
'95 E420 116K

Perfect! thank you for the information good sirs and Arthur Dalton, thank you for the details, it makes life a little easier.

now if I could just track down this Viscous Fan Clutch that I hear is available.