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.

Original fan clutch was not working; it should have been fully coupled at 90 deg C. Your 'overhauled' fan clutch sounds like it has nearly the opposite problem - it should not engage when cold.

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

the fan is coupled on startup but decouples in about 1 minute then freewheels till the temperature comes to about midway between 80 and the mark above 80 (which I believe is 100) and just sits there. Causing the fan to be engaged nearly all of the time under normal driving conditions.

funny bit is that there is only a very slight temperature difference (never actually touches the 100 mark) after the refill but the A/C performance is off the scale now, freezing cold in TX weather.

I think that either I put in too much fluid or I put in too thick or both.

I would strongly encourage you to part with $140 for a new clutch from the dealer to minimize the risk of damaging a very expensive engine. Rebuild other things like brake calipers, axles, injectors, alternators, fan motors, etc.

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2009 E320 Bluetec 117,000
1995 E300D 306,000 Sold
1996 Ford Taurus LX 130,000 Sold
1985 300TD Still 225,000 Sold
2016 Ford Fusion 24,900

update - I have a nicely working fan clutch now, and the temps are controlled at 90 to a smidge under 100.

I removed nearly 9cc of the oil I put in and pushed in 3 cc of new 3000 cst oil - left the clutch sitting upright for 12 hours and voila - perfect dead cold start has the clutch locked for about 5 seconds and after a drive with A/C the clutch couples and tries to follow sudden acceleration but cannot keep up completely. decouples at 3000 engine rpm too.

so if you have a 606 engine car with a BEHR clutch that is not completely toast, you can save it, spend 10 bucks at the hobby store - and borrow the wifes oven for 10 minutes. Just remember a little less oil is much better than a little more

When a hot engine is shut down the fan stops within 2 or 3 blades. Previously it was freewheeling on a hot stop.

I also fixed my high speed aux fans - green relay had its 30A fuse blown - new fuse and the fan test ok with the 2 pin plug on the front of the cyl head disconnected.

Good stuff, I need to make this repair on my OM606. I'll be calling the local hobby shops and the Toyota dealers (looks like Part # 08816-03001 is the 3000 cst oil).

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

How can you safely check the operation of the fan clutch to know that it is engaging?

By using a digital strobe light that indicates rpm.

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Jim

As an aside, those stobes are awesome for balancing/truing fan blades. You set it to the correct rpm and it "stops" all 4 blades in the same place. With a Sharpe mark on each blade (1,2,3,4) you can see which blades are out. Then you just bend away!
Back to your regularly scheduled programming....

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

Guys I 'have been doing some research on this.

I replaced the fan clutch on my 95 E300D about four months back with a then brand new Berh unit. I get Cool running AC, when it get's above 90 degrees and the car is parked under the sun for too long I notice that if I don't move the car (sit in too many traffic lights) the AC's performance drops from "freezing cold" as my wife often complains about having to wear sweaters when in my car to ok cold when compared to when the car is moving. Both electrical fans are in good working order. but they don't seem to go into the second speed at any time though. (I have tested the second speed on the fans by disconnecting the temperature sensor by the upper hose and the fans automatically climbed onto the second speed) not sure when that second speed is supposed to kick in anyways.

Took it to my trusted AC guy and he mentioned that the fan clutch is no good (4 month old) based on firstly because when we turn off the engine the fan keeps free spinning and when the engine is off it free spins)

I put my hand with a rag of course onto the Fan with the engine on to see if it was engaged, At that point the car must have been a bit below what we think is that is 100degrees (the line with no number just between the 80 and 120) and tried to stop the fan. I was able to stop it but it was very hard to make it happen. The car had not reached 100 degrees and it did not seem to be moving towards that direction. He said that it looked good on the pressure side at 34psi. (is this correct for this car?)

Car is Black on Black and in south Florida weather which surely does not aid the scenario

Does this sound like a good working fan clutch?

I would really appreciate any input.

Thanks

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CM

when the clutch is engaged, you will definitely hear and feel the fan, it roars really really loud and also moves enough air to basically freewheel the front aux fans just on air movement.

In summer the fan clutch will definitely be heard if the ambient temp is about 80F and the engine temperature is about 95-100C. You cannot expect it to heat up if the hood is open and if the engine fan shroud is missing. It needs to cook in order to operate.

This creates another point of failure, blocked radiator/condenser fins. If they are blocked with dirt,twigs,grass etc. air wont move through it and hence the fan clutch will never heat up and never work.

Take a strong flashlight and shine it through radiator and see through the condenser if you can see the light passing through. If not you have a blocked situation and need some cleaning to do.

The bottom part of the front aux fan shroud in our cars is a nice trap for grass,dirt,bugs,road grime and needs to be cleaned periodically.

If you pass all above tests and still have a dud fan - it has leaked its silicone blood and needs top up. if you are not upto the task (its an ordeal the first time) then buy a OE 1999 E300TD fan clutch - its made by Horton and is far better than the poor BEHR unit that MB installed in the 1995 E300D.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

I don't even run a fan shroud and the engine never gets above the 1/2 way line above 80 even in hot traffic. Radiator is fairly new.

I'm wondering if yours may just be a little low on freon. Find someone that can recover, vacuum and recharge and make sure the correct amount is in it.

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Jim

Thanks guys.

I checked the shroud and it looks all good and perfectly placed on the bottom, side and top portion, checked that while I was down there investigating a bit.

I checked the condenser with a flashlight as suggested by Zulficar earlier, looks good (not sure about the bottom of the electric fans shroud.

Anybody knows the correct freon pressure on these?

He mention that it was dead on at 34 psi. Not sure where he got that from though.

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CM

I'd suggest you remove the radiator fan, and tip the radiator forward so you can clean between the condenser and radiator. You might also want to clean between the condenser and condenser fans.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Thanks for the advise guys.

I finally got a chance to take a closer look at the engine radiator fan shroud and noticed that the lower passenger side guide was out and allowing air to escape a bit. so I took it off and clipped it on correctly.

Compu_85 about cleaning between the condenser and the condenser fan. Any instructions on that I would want to take a look and exercise your suggestion.

Does the front bumper have to come off, or is there an easier way around it?

Any advise would be greatly appreciated.

As always thank you guys for the advise and direction.

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CM