1995 E300D fan clutch

[Zulfiqar]

Yesterday I was bored and decided to inspect the cooling fan. It was testing as

stone cold start - fan was engaged at idle - but would decouple at anything above 1000 rpm
engine at full operating temp - fan would freewheel - with literally no air movement - even with temps at 100 on the needle.

So I removed the clutch (which took me half n hour because the centre bolt was plugged with dirt)

cleaned out the fins of the clutch and removed the blade wheel.

You can fill a 606 clutch, remove the RTV, and slide the bimetal strip to disengage from its captive position the RTV is what prevents the bimetal from going down. remove metering piston and seal and proceed to bake the clutch in the oven at 225 degrees F for about 5 minutes, remove clutch from oven.

I filled it with about 15cc of 7000 cst silicone diff lock oil from a hobby store. You need to muscle the srynge to push the oil in the metering piston hole.

point to note is that you may think that the bimetal can only be bent out of place, DO NOT BEND as it would make the fan engage at 80 degrees or even be permanently engaged.

NOW the result

When I start the engine cold - the fan is engaged, and my GOD it pulls an AWFUL lot of air - and sounds like a truck. It takes a good minute or more to decouple. and when the engine gets hot about 90 to 95 celcius with the hood closed - the fan couples and you can hear it too - For all the time I drove today it did not decouple fully, I could hear it the roar whenever I accelerated, I had my A/C on too, and it was cooling super nice because of the fan - but the temperature never touched the 100 mark.

I have not seen a proper working OM606 fan, was my original fan correctly working or is my refurbed clutch coupling too hard? I dont want the fan to explode because of too much coupling.