86 190E 2.3-16 axiliary fan problem
 

i just had the engine in my car rebuilt because a clogged catalytic converter burned my cylinder 3 and 4 valves.

no when i sit at a stop light the temp gauge steadily climbs till its almost in the danger zone and the the fans kick in. the temp gauge is accurate because i check it against the oil temp gauge on the center console.

id prefer if my engine didn't get that hot because if could damage the head and these heads are not cheap.

how do i get those fans to kick in earlier or run stronger.

I'm no expert but my first thought as I read your issue is check your radiator. Make sure that air can flow through it freely and the ac one too. Make sure all of the fins are still in good. It may just need a good cleaning..:)..

Get yourself a 100 degree C. Aux. Fan Temp. Switch.
Also, is your magnetic clutch fan operating?

if by magnetic clutch fan, you mean the one thats not on all the time and not driven by the engine, then yes it is. but ive never really checked, i keep my windows open so i hear the aux fan come on.

where could i get one of those fan switches, and is it an easy DIY

So you are stating that your clutch fan DOES operate when the coolant temperature rises?

You should be able to get the above mentioned aux. temp. switch locally. If not, then click on Buy Parts at the top of this page and order it from them. Yes, it is an easy DIY replacement. If I were you, I would go ahead and replace both temperature switches...you DON'T want any overheating situations.

okay, i just checked the magnetic clutch fan today. i was getting it confused with the electric fan.

the clutch fan is spinning very slowly in comparison with the engine. it was spinning at less than a RPM at idle and the car was very hot.

ill post a video tomorrow when i have my camera

now what

The aux fan is controlled by the temp sensor at the front of the block. To test, remove the wire harness from the sensor and use some insulated wire to jumper the harness contact. That will simulate the sensor closing the circuit and the fan should spin up since the magnetic clutch will be energized. That suggests that the sensor is dead.

If it doesn't spin up when jumpered, then it is either the wire harness or the fan clutch.

If your magnetic fan is not working it's nothing to do with your Auxiliary fans. This only comes into operation when the engine gets hotter than the magnetic fan can cope with.

I suggest that the shop that did your head repair has made some sort of error. Take it back to them and tell them what's happening. Get their mechanic to check out the refit job.

The last time I had a valve job done on my 190e the Indy shop let the Apprentice put the car back together. He left something off (bowden cable bracket) and this was not checked by the mechanic.

<<If your magnetic fan is not working it's nothing to do with your Auxiliary fans. This only comes into operation when the engine gets hotter than the magnetic fan can cope with.
>>

Correct.

And that is not the aux fan. It is the magnetic fan.
The aux fan is the electric fan in front of the AC condenser.

The mag. fan comes on @ 100c..the aux fan comes on High speed @ 105C, and the LOW aux fan is triggered by the AC head pressure.

So, here are the 3 test for all fans

Mag Fan- jumper the red coolant temp sensor..that engages the magnet for the main fan.

Aux fan HIGH speed ..pull the 2 wire connector off and jumper .

Aux fan LOW speed...jumper the 2 wire sensor at the drier with the 6" long pigtail wire harness. That gets low fan.

These test each fans circuit. If NO to ANY of these test, then you have a power problem and first step is to check the fuses for each circuit.

As Iv and MTI suggest, your problem looks to be the mag fan circuit, because your aux fan is coming on @ 105, whereas , if your mag fan was working correctly, the car would not see that high a coolant temp b/c that fan would come on @ 100c, thereby not requiring the high aux fan to come on.

assuming that the magnetic fan is working. how would i get it to come on at a lower temperature. 100C is hot

I would temporarily jumper the low fan sensor [ across pigtail wires @ drier] and see if that added airflow solves your overheat problem first.

so whats what here

I don't have that exact schematic , but this will be close and you can verify by trying each one..
First, you do not have the blu 2 wire sensor earlier mentioned b/c they did not come out til 88.

So ..Try this:

#4 The red one should be the mag clutch fan ..jumper to verify clutch mag engagement

#1 The single wire one should be the temp gauge ..disconnect it and see if gage stops working to verify

# 2/3 The blu 3 wire one is 105/115 switch..that is for high aux fan and ac comp cut-out. Jumper pins 1 [ br/gy] and 2 [ br] for high aux fan.

#5 is most likely FI temp sensor. Can not make it out.

Still want you to jumper pigtail leads at drier so we know if the low fan works or not.

so Arthur, thanks for all your help. but im going to need a walk through as i am not electrician. ive never had to deal with a problem like this before.

and i have no idea what the drier is.

Here you go. Located at the left front of engine bay, behind driver side headlight, down low. For Arthur's test, disconnect the pigtail leads and jump the brown/blue stripe and solid brown wires. Low fan should come on.