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Discussion Starter #1
1985 500 SEC

I need a new mechanical 9 blade radiator fan, and while a new clutch is locally available, an undamaged fan is proving difficult to find in Thailand.

My hope is that a fan from another MB model, or even a different car will fit. If I have to buy a matching fan clutch that is fine as the stock one is suspect and shows signs of being "serviced" by a local mechanic

Worst case I will have to convert to electric fans, with the new problem of finding a higher output alternator
 

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1990 SEC
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4,088 Posts
1985 500 SEC

I need a new mechanical 9 blade radiator fan, and while a new clutch is locally available, an undamaged fan is proving difficult to find in Thailand.

My hope is that a fan from another MB model, or even a different car will fit. If I have to buy a matching fan clutch that is fine as the stock one is suspect and shows signs of being "serviced" by a local mechanic

Worst case I will have to convert to electric fans, with the new problem of finding a higher output alternator
The easiest solution is to source a new (or good used) clutch fan assembly. They're relatively easy to find on sites like the US eBay.

Converting to electrical fans is a bit more complicated, and involves a few trade offs.

As you point out, you'd have to upgrade the alternator from the standard 85 amp unit to something like the 150 amp unit from a 600SL. How easy are those to come by in Thailand?

You also need to upgrade and install new wiring to power the electrical fans.

Then there is the issue of controlling the fan. The viscous coupled OEM fan is variable speed. Which means that it's fairly quiet when the engine is cold. An aftermarket setup will either be on/off using a simple temperature switch in you cooling system somewhere, or a variable speed setup using a PWM control unit going off a sensor installed somewhere in your cooling system.
 

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Two '87 570SECs, one '87 560SEL
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Axel is right. I've BTDT. My beautiful dual electric fans cooled the 560SEL great, but the stock 85 amp MB alternator died in two weeks. Had the alternator rebuilt into a heavy duty 100 amp unit. Lasted under six months. Had a custom 140 amp alternator built and that's still working, but the fan controller died. #$%^& Bought a $50 viscous clutch assembly off eBay and had the radiator rodded and flushed - all is well. I live in Las Vegas, as hot as if not hotter than Thailand.
 

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Discussion Starter #4
The cost here is the roughly the same for a used fan, new shroud, and new clutch, as an electric dual fan solution using a PWM controller.

The simplicity of the stock system is appealing, but there must be a reason why the dual electric fan conversion is popular in hot climates, and why new cars are electric. While it also takes HP to drive a big alternator, it should be less than driving an engaged propeller.

Thanks for the input, and I am still still hoping for a different mechanical fan alternative..................,
 
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