Mechanical Vs Electric Fan

[dfeldt91]

(I tried to search but the search function has never worked for me on this site. Not sure why..just blank page below the header.)

I have an electric fan that does not currently work and a belt driven fan on my VW Passat. I am doing a bunch of mods and would like to completely remove the belt driven fan to save fuel but am not sure which is likely to be more fuel efficient. I have a feeling it is the electric fan, especially if only operated when needed via in cabin switch.

After I remove the power steering pump assembly the serpentine belt will be routed just close enough to barely touch the fan so it is likely not going to work with minimal contact anyhow.

Anyone else have experience with this and care to give some input? Thanks!

[t vago]

I would not trust an in-cabin switch for fan operation. All you'd need to do is forget to operate the fan, just once, and *BOOM* overheated engine.

You would do well to leave fan operation to your car's electronics, and get a larger fan. You'd also want to construct a fan shroud to make your fan more efficient.

I've done this modification to my truck, a 2000 Dodge Dakota Quad Cab, and I am going to do this to my newest acquisition, a 2001 Dodge Durango. It currently is sitting in my garage, slowly being put back together after I swapped in a replacement engine.

[redpoint5]

Hey, another person from Salem (that's where I am as I write this)!

The electric will be more fuel efficient, especially in our climate where we rarely need the fan. How much more efficient I'm not sure. You'll want to leave the fan control up to the vehicle electronics to switch on. It's too easy to miss an alarm that warns when the fan needs to be manually operated, especially that one time you let someone else drive the car.

I recall my friend's VW had 2 fans, just like most Japanese cars. 1 fan turns on whenever the AC is operated, and the other turns on only when the coolant temperature goes above a set threshold (215 F in my Acura). How many fans are in your Passat?

I've found that my cooling fan never turns on when I run the AC, as the airflow from the AC fan is sufficient to keep coolant temperatures in the normal range.

[Frank Lee]

When I was a youngster I put a Toyota engine into my Triumph Spitfire. Space was so tight I had to relocate the radiator forward AND go e-fan... but there weren't that many e-fans to choose from then. I found one in the junkyard from a Simca and had to reverse the blades to make it into a pusher, mounted in front of the radiator. Put a toggle switch on the dash. Start it, drive. Watch the gauge climb, turn it on/off as needed. Easy.

Went fanless on the F150. There have been a few situations where an e-fan would have been nice. If I ever get around to installing an e-fan I'll probably control it with a simple toggle switch. When it gets hot it tells you: gauge shows it, you might get a whiff of anti-freeze, you might hear boiling, you might see steam. It's not as if the thing will go into uncontrolled nuclear meltdown right away. Don't ignore it either, though.

Sport Coupe is fanless too. Never gets hot even with the grille block but then there's no a/c and I don't sit in traffic either.

[cRiPpLe_rOoStEr]

Get an electric fan and you won't regret.

[ShadeTreeMech]

I agree that toggling a fan manually is not that difficult. But I also agree that someone with less mechanical sympathy driving your car would be a bad thing with a manual toggle.

However, I also once had an 85 Maxima which didn't have a functioning water pump which easily survived being driven during a winter in my temperate Arkansas until my less wise and youthful self decided to look into it to realize the water pump belt was broken. Surprisingly it never overheated.....

[Frank Lee]

Nobody else drives my stuff but if it's an issue tape the toggle so it's on for the duration of their using it. Won't hurt anything.

[user removed]

Originally Posted by ShadeTreeMech

I agree that toggling a fan manually is not that difficult. But I also agree that someone with less mechanical sympathy driving your car would be a bad thing with a manual toggle.

However, I also once had an 85 Maxima which didn't have a functioning water pump which easily survived being driven during a winter in my temperate Arkansas until my less wise and youthful self decided to look into it to realize the water pump belt was broken. Surprisingly it never overheated.....

Air over the fan turns the fan and the pump, (even with a fan clutch) just don't sit idling for a long time, or shut it off, just keep moving or engine off. That's the reason I question the swap, if there is enough air flowing through the fan becomes a propeller driving the pump.

regards
mech

[TimV]

In my case i have an waterpump witch is driven by an serpentine belt and an separated viscous clutch with fan so the fan is not mechanically directly connected to the waterpump.

Hopefully i have in a few weeks the time to do thus swap. I have 2 fans just laying around doing nothing...

The only problem i face to. Is how to turn the fan on and of...

[user removed]

Drove my 76 Z car home 20 miles when the OE fan belt snapped at the seam. With only airflow driving the water pump, using engine off coasting, the coolant temperature was actually LOWER than normal when I arrived back at the shop.

regards
mech