Flex Fan Or Electric Fan?
 

Would replacing my clutch fan on my 420sel with an all electric fan or with a flex fan make any noticable or worthwile improvents to cooling while idling with the a/c on or power?

The quick answer is no.

Electric will not move as much air as the OEM. You will have cooling issues.

The fan clutch will disengage when the RPM is greater than 3000. So that is as good as it gets.

He's right no it won't improve the cooling situation.

But he's wrong that it will make it worse, because you CAN get electric fans that move as much air as OEM.

The only improvement and electric fan will have, and its a very very minor almost non existent one on a V8 engine, is lack of parasitic drag at idle compared to the clutch. On a car like the 190E 2.3 on the other hand the difference is very dramatic especially in stop and go traffic, three guesses how I know ;)

The advantage to an electric fan is that at idle , they move more air than an engine driven fan simply b/c they have FULL RPM at idle, an engine fan does not b/c it's speed is engine rpm dependant. That is why Benz uses aux electric fans for both coolant temps and a/c high side pressure aids...it is at idle/stand-still that these fans do their job of keeping both temps and pressures in check b/c engine fans have an airflow volume problem at those low rpm/idle conditions.
When a care is traveling, you have airflow from vehicle speed and these electric fans are not even needed.

Thanks Arthur I forgot about that advantage too.

try a product called water wetter it will improve the temp connection between the antifreeze and the radiator tubes and allow to run cooler.

I found this article to be very helpful. It even shows you how to mark the Prestone antifreeze tester to get a 35%/65% antifreeze/water ratio. I found that all three of my cars had too much antifreeze. Thanks Jim.

http://pages.prodigy.net/jforgione/MB_WW.html

Let me "fan" this fire a little bit. Last year the fan clutch on my '91 300SE locked up due to a dry bearing. Once I got the clutch and hub off, it was winter by the way in Georgia, I drove around with only the aux fans. They never kicked on and the temp never climbed much above normal, even in town. I bought an electric fan rated for a V8 engine, did some engineering with a genuine Benz fused relay out of a wrecked car, wired it (soldered) through the A/C circuit at the compressor, now I have the needed cooling when the A/C is on. I can hear the aux's kick on but this is normal in summer when running A/C. I've noticed that I get a little better mileage due to the engine not having to pull the fan. My 2 cents

I wanted toknow because I was trying to get better air conditioning performace in stop and go traffic because I do a lot of city driving in my work route and I'm about to move to a worse location. The fuel mileage my car gets is horrible with the a/c it seems and any extra mileage and/ or better cooling will help.