Fan clutch or no fan clutch, that is the question

[ScottinSoCal]

Originally Posted by karburn

One post above gave me the idea that the fan should spin freely when the engine is off, regardless of temp.

The fan is thermomechanical, not electrical. Engine running or not doesn't matter, just the temperature. There should be more resistance when hot, less resistance when cool. Try it in both conditions and see how much difference there is. If there isn't any difference, get a new clutch.

[slik560]

I think I got it now...thanks. Hope it's an easy DIY. I'll probably use the Behr replacement in lieu of the $$$$$$$$$$ OEM. Thanks for your time.

[Djenka018]

So I can take it that none of you here have the fan with the velocity dependant cluch?

[ScottinSoCal]

Originally Posted by Djenka018

So I can take it that none of you here have the fan with the velocity dependent clutch?

No, you're the only one.

[Lookout1979]

And this site seems to have everything and maybe be the cheapest:
73 1973 Mercedes 450SL Fan Clutch - Cooling System - ACM - PartsGeek $169.94

Anybody use this "PartsGeek.com" site?

OK. Benzbin.com looks cool (partsbin.com did not) and they've got a fan clutch for about $195 (a little more expensive than PartsGeek.com) Mercedes Parts - Mercedes Benz Parts - Discount Prices - 1973 Mercedes Benz 450SL Fan Clutch

After a few minutes of browsing and finding on BenzBin: - no wiper motor, and - items like "motorcycle cover", I think i like PartsGeek better so far. Time will tell since I've yet to order anything.

My experience w/ partsgeek ended up in horrible customer service (what CS there actually was)... and it's a HUGE hassle if you have to return anything

[rowdie]

Another NO vote on PartsGeek.

[Fonzi]

Good info. Thank you on the PartsGeek info. I'll be sure to stay away. For now I think Rockcrusher is solving all MY problems. Gotta love this site!

[slik560]

I ordered a replacement fan clutch from Performance Products. When I had the new unit installed (I'll spare you all of the details) I found that the new unit was too short; ie: it put the fan too close to the belts/pulleys. I took it out and disassembled everything [again] and put the old unit and the new side by side. See photo:


The old clutch is on the right. Note the attachment tabs for the fan blade assembly. There is a 5/16" difference. The new unit puts the fan 5/16" closer to the motor, which is just not acceptable. I sent the part back to Performance Products today. VERY dissappointing.

SO....now the choice is to order one from another source and take my chances, or punt and go the flex fan route. I would need to find one that moves enough air for this motor. So far the ones that I see online are good only up to 4L motors.

[Fonzi]

Originally Posted by karburn

I ordered a replacement fan clutch from Performance Products. When I had the new unit installed (I'll spare you all of the details) I found that the new unit was too short; ie: it put the fan too close to the belts/pulleys. I took it out and disassembled everything [again] and put the old unit and the new side by side. See photo:


The old clutch is on the right. Note the attachment tabs for the fan blade assembly. There is a 5/16" difference. The new unit puts the fan 5/16" closer to the motor, which is just not acceptable. I sent the part back to Performance Products today. VERY dissappointing.

SO....now the choice is to order one from another source and take my chances, or punt and go the flex fan route. I would need to find one that moves enough air for this motor. So far the ones that I see online are good only up to 4L motors.

Should have orderd from PartsGeek.






:-)

Just kidding!


When I installed the AC belt on mine, I was really thinking that maybe I was going to need to remove my fan. I was just barely able to squeeze in my new AC belt after a lot of patience. I wonder if my fan clutch is a 1/4 inch too short too? Interesting. Thanks for posting!

[slik560]

I was able to get the correct fan clutch from my local MB independent shop at a decent price and it fit perfectly. I cannot believe how much air the thing moves now. I did some long highway drives, each ending with some deliberate stop-n-go driving, and the temp gauge would only go slightly above normal....and then go back down when the car was moving at speed again. I think I have this part of my stalling-while-hot problem fixed.

The downside, if you could call it one, is the noise. The fan now moves so much air that the car sounds like my grandmother's old Hoover vacuum cleaner when accelerating. No kidding. While the sound is reassuring in that I know the radiator and motor are now getting more air, it actually drowns out any exhaust note. So...there is only one viable solution:

MAGNAFLOW! Time to start the exhaust rehab project: Magnaflow cat, delete the stock resonator, new Magnaflow muffler and stainless piping in between. I can't show my face at the next autocross with the car sounding like a turbine, now can I???