The fan still spins when it's cold but it's not as high as it would be when warm. There will always be some drag in the visco clutch to pull the fan along.

The only true on-off engine fan is one with a dry clutch. I know the 190E 2.3 uses and electric clutch (like an A/C clutch) to hold the fan and it truly freespins when it's off (see picture attachment). Most large semi's use the same idea using an air-actuated clutch.


Go out and move your fan by hand. It will have some resistance.

I guess I should edit it to point out the fact that it's basically a 240D by body badge, not function.

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The clutch fan I mentioned was taken from an early-80s 300CD. I originally intended it to upgrade the cooing system on my '60 Fintail, after I add a hang-on AC unit. But I already have an extra clutch-fan from a '70 W114 250C parts-car that I used to own.
Meanwhile, my 240D fixed fan is indeed a plastic five blade, but my 300CD clutch-fan is a six-blade aluminum fan. I know I'll need shorter bolts to fasten it on the waterpump. I'm hoping, if nothing else, to cut down on some of the roar at highway speeds.

Happy Motoring, Mark

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DrDKW

Better recount, it's got 5 blades.

it may help a little. it would be interesting to take a decible meter and take before and after readings.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Well, maybe yours does, but I have the fan in question right in front of me and it's got six.
However, this fan may not have originally left the factory with that 300CD - the part number on the fan blade assy is 108 205 10 06. The fan clutch part number is 000 200 04 22.

Happy Motoring, Mark

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DrDKW

That must not be the original. The stock fan is the 5-blade on the left. The one I use is the updated 9-blade plastic on the right.

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My spare is like the six-blade aluminum fan on the left.
With the sudden arrival of cold weather, I think what I'll try is to remove my fan completely, wire a temporary switch to the aux fan, just in case I get stuck in traffic, then go on a test drive to see if there's any noticeable difference in noise or power.

Happy Motoring, Mark

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DrDKW

good idea.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

All 3 fans- 5blade, 6blade, 9blade are available thru aftermarket houses like performance4benz. My 300D turbo has a 6blade.
interesting mileage figures posted in this thread- my car gets 28-29 mpg in mixed driving. Also it runs hot- 100C minimum. I'm definately not removing my fan- might try the 9 blade though...

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'83 300D Turrrbo 295K miles

i would be trying to get that temp down if i were you.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

For sure. 100 is way above normal.

The fan does spin when cold, but I don't believe it's using that much power. You should be able to stop it from spinning without much force (i.e., with a rolled-up newspaper).

They do have a tranny cooler in the radiator, I'm not sure how much heat it makes in stop and go traffic. My radiator is original, so that may explain why I need the fan. YMMV.

they are not evenly spaced, but there are 6 blades...
John:fork_off:

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Humm.. Learn something new every day. I guess I'll keep my eyes out for one in the parts yards.

Yes, I've removed the fan both on my 6.2 Chevy Diesel Van and Mercedes 300D in the winter from November through February in Iowa. My Van would noticeably cool with temperature gauge drop when idling in the winter with the mechanical fan, and when removed it would stay warmer and heat up more quickly. I did install an electric fan in the 6.2 diesel van as a result of this experience. Remember, the cabin heater is a cooling radiator as well.
I've not had an overheating problem. The radiator acts as a cooling reservoir after sitting at a light and dumps cold water into the engine block while waiting for green. Diesels produce significantly less heat when idling than a gas engine and results in using less fuel & greater economy.
Of course you'll be more thoughtful about outside temperature and your temp gauge. I don't track mileage closely enought, however there would be small economy improvement here. Think about the savings when you add up hundreds of thousands replacing their unneccessary mechanical fans!
This is my experience and works for our diesels in the winter. You decide!

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'96 C220 138,000mi, '95 E300D 239,000 mi., '87 300TD 214,000mi '88 6.2 Turbo Diesel Chevy Conversion Van 253,000 mi.