Done within 2 weeks of purchase in March 2004. An update after the fan clutch repair and 4 days of commuting (BTW, the fan now stops immediately when I hit the manual stop).

Morning temps warming up and I have been running the AC full time. Traffic not too bad the last 2 mornings with no significant stop and go--about a mile altogether of the 34 mile drive. Temp stays at 100c or below.

Afternoon temps are nearing 100C with the interior of the car heated to 140F when I get in. Yesterday, about 1/3 of the 34 miles was serious stop and go. Several stretches of stop and go of at least a mile and 2 stretches of 3-4 miles in which the max speed was 20 or less and most was at crawl speed to low to show on speedometer. Temp (according to guage--I will check the sender and guage this weekend for accuracy) was at 100C before the first stop and go and it then began to rise, but mostly stayed at approx. 110C until the last 3 mile stop and go and it was a bad one). By the end of that stretch, the gauge was nearing 120C, so I hit the defrost button and the guage went back down to about 105C. Turned the AC back on and drove the remainder (about 8 miles, mostly moving between 30 and 55 mph) with 105-110C.

Currently, I have the original thermostat back in and it does pass the tests. The aftermarket one I had bought failed all tests. Anyway, I have a new MB t-stat to test and install this weekend. I plan to pull the raditor and wash it and the condensor this weekend. I plan a good flush at the same time. The radiator cap is a new MB--I have not checked for actual bar pressure, but it does hold. I am running a 50/50 mix of coolant, but I also have new MB coolant to install after the flush.

NO water in the oil;
NO oil in the water;
NO water blowing out the tailpipe while idling either hot or cold;
NO known water coming out of the overflow, but possible while driving if the cap is not holding pressure; and
NO coolant leaking from water pump, hoses, reservior tank, radiator or inside the car.

But I had to add about 1/2 gal of mix after having topped off on Monday. So...............?

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1984 300SD 326,997 miles and counting . . . No wait, my odometer is still dead

Has anyone replaced their clutch fan all together with an electric and had success?

thank you, that was forward thinking...

david

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newfane, vt
84 300td 223k modified greasel conversion (sold)
92 300d 2.5 185k with frybrid kit

You can get syringes and different gauge needles at your local Southern States Farm Supply without being looked at like a mainlining fiend. I use a 14 gauge to inject glue-fairly viscous- so that should work for the fan clutch.

Scot

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"Be kind to thy ass for it bears thee" -John Muir

83 300TD & 84 300D

OK, so it's not a diesel, but the clutch is pretty similar. My 300E has been running too hot in summertime, especially in slow stop & go conditions. I verified that the electric fan was working properly, and yes, it kicks on high speed when coolant temps exceed 105°C, as it should. But the electric fan isn't enough to cool the engine by itself, it's only there to help the main fan. With the engine temps at 110°C, I killed the engine, and the fan kept spinning for several seconds... it was definitely not coupled. Radiator fins are clean and there was no cold spot in front of the clutch. Looked like a good candidate for the silicone refill theory.


The Surgery:
Soooo, I pulled out that half-liter bottle of 12,000 cst silicone fluid which I purchased a while back (from someone who bought a gallon of the stuff, and was re-selling smaller quantities.) The bi-metallic strip (BMS) is simple to pop out on the M103 clutch, it's more glued in place than mechanically locked in, believe it or not (unlike the OM60x clutches I've seen.) With that out, I used the previously mentioned method of heating the clutch, and slowly dripping in the fluid as the clutch cooled. I'm not sure how much I ended up putting in, as I didn't measure the quantity. I lightly clamped the back side of the bearing in a vise, so I could spin the fan. Before I started it spun easily with no resistance. I stopped filling when I noticed a decent increase in resistance. I glued the BMS back in place with a dab of RTV at each end, same as it was originally.


Results:
Well... good & bad, I suppose. First the bad. When cold, the clutch is fully coupled, and doesn't appear to de-couple after a few seconds (as a normal clutch would). The good news is, when warmed up (after a 20-minute test drive), the clutch does de-couple, and appears to operate normally. I let the car idle (in 100F ambients, with the AC on max) long enough to get the engine temp to about 100C, and around that point, the clutch coupled as you would expect (due to the BMS expanding). Now, I couldn't find anything in the M103 service manual about temperatures or engine RPM's, but when hot & coupled, the clutch stayed coupled up to at least 4000rpm... it finally appeared to back off above that speed (I think the OM603 clutch is supposed to stay coupled up to 3500rpm when the BMS is triggered.) Hot or cold, the fan now stops very quickly when the engine is shut off. It's not instant, but I'd say it stops within a half-turn. Oh yeah - so how does it cool? MUCH better... so far, I haven't seen the temps over 100°C yet. I'll keep an eye on that though. Remember, this was compared to an old, shot clutch that was probably just floating along at idle speed all the time. I was trying to avoid plunking down ~$175 for a new fan & clutch.

Side note - the M103 clutch uses an 11-blade plastic fan. I may be doing this same procedure to a friend's M103 clutch, if so, I'll take some photos next time. I'd also prefer to locate some thinner fluid (6,000 cst might be good), at least for the clutches with plastic fans.



Best regards,

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Dave
Boise, ID
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Thanks.




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ASE Master Mechanic
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1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

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too bad I didnt take pictures while filling my OM606 clutch.. - But I can take the fan out in about 3 minutes now, and show how to take out the BMS and pin then fill.

Which fluid did you use for the 606?

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

I did,with a 16" Mustang size electric fan.I used a adjustable thermo switch but they burn out.I have now a 30amp toggle switch inside car.I harly use fan,only when in stop and go traffic.I bought my stuff a Summit Racing.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

You have to couple the thermo switch to a relay because the switch isn't designed to take the load of the fan.

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

Will this work on the clutch on my OM602 Turbo?

Thanks!

Refilling is a massive PITA. Just get a new aftermarket ACM clutch and save yourself hours of headaches.

Okay. I was wondering because I am not sure of the condition of the one I currently have and I also just picked a second one and I do not know the condition of it either. So I figured I would mess with the second one and then swap it out if I could get it to work properly, if it is not already.

To make the electric fan come on at 100c I replaced the brass heater temp switch that is on the thermostat housing. The purpose of that switch is to not allow the cabin heater to come on till there is hot water. I can figure that out for myself. The 100c switch has two pins and dose not ground it self.
The fan comes on when the ground side closes so I ran a ground through the new temp switch and joined to the brown ground wire coming of the AC temp switch on the dryer. Now either switch can turn on the electric fan.
I have since installed a new/used fan clutch that solved my over heating problem so the electric fan is mostly a backup but will come on the odd time in traffic on a hot day.

__________________
1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

I didnt notice that I was asked a question about the fan clutch

I used approx 9000 cst fluid in the OE OM606.910 fan clutch and about 6 or 8 cc - which btw is a stupid clutch, it acts and sounds like a old beat up truck from the 70s fan clutch but it keeps the temperature under control.

I then got a leaky genuine 606 turbo clutch and its a bit different in working, at idle speed I can feel air movement at the fan even if the clutch is not engaged and roars to life when hot.

In any case the clutch is a fuel saving and speed limiting device for the fan - if at any time you hear the fan engaged even at full engine rpm, immediately take action, The consequences as disastrous.

if you are comfortable with tinkering - refill the clutch, bake it and use the heat to aid the fluid pull, Do not put excess in otherwise it will cause pain. Once done - make sure to silicone the BMS on the clutch

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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)