mrmalin92

So my 85 190e is overheating. It seems like the bigger yellow fan doesn't turn on when its supposed to. It just spins slowly and can be stopped by my hand, even turned backwards. The aux fan doesn't turn on either when using the ac. I was told it needs to be charged in order to work. It looks like someone already converted to r134a. So if I recharge it, will it turn the fan on? Some help with my fans please.

MTI

For your year, the fan mounted to the engine is an electromagnetic unit, not a hydro-viscous unit, so you can test the fan by shorting the terminals on the engine temp sensor at the front of the cylinder head (red). If the fan spins up, then the fan motor is okay. If not, then either the temp sensor is bad (likely) or the fan motor is burned out.

mrmalin92

How do I go about shorting it?

MTI

I used to use a screwdriver blade across the terminals.

mrmalin92

Which one is it exactly? There is two red ones. One with three prongs, one with two. And a black one with two prongs

MTI

The three prong red sensor switch controls the auxillary fans, the ones at the front of the radiator, so I misspoke. There should be a wire harness from the main fan (light colored plastic fan attached to front of engine/water pump) and will lead to a two prong sensor on the cylinder head. With the ignition in the "On" position, but the engine off, short the plug connector harness with insulated wire into each hole. There should be a click from the fan clutch signaling that the electromagnet has engaged. If so, replace the sensor (cheap), but if the electromagnet is silent and the fan can be easily spun while shorted, then the magnet clutch may be gone.

mrmalin92

So I shorted it like you said and both fans came on immediately. They were quieter then I expected. This means its the sensor that is bad?

MTI

Yes, you're in luck. The sensor is quite inexpensive online.

mrmalin92

So just checked it again just in case. The aux fan turns on. The yellow one spins slowly but I can stop it and turn it back with my hand. Is it still the sensor? Or is it the fan electromagnetic clutch as well?

MTI

It's at least the sensor, however the main engine fan should be tougher to stop spinning. I would start with swapping out the temp sensor switch.

mrmalin92

Now I'm having another problem. The car seems to be randomly stalling. No random noises or issues. The engine just cuts off. I'll post some pictures tomorrow

mrmalin92

Believe I found the issue, what's this called? Looks like its corroded

mrmalin92

Could I just solder the plug or what?

mrmalin92

The fuel pump is somehow stuck on now. Had to disconnect the battery to turn it off

mrmalin92

I fixed the plug. I believe it was messing up due to the fuel pump relay, the fuse was also blown in the ovp relay