It probably isn't an issue with modern, densely finned aluminum radiators where most of the oncoming air is attenuated. However, our radiators have large gaps and significantly more thru-flow. Food for thought.

 

That's another thing that I had not considered! So other rad shrouds have flaps that open to let airflow pass through?

 

Yup. The flaps are pushed open by oncoming air at speed. When the fan is engaged at low speed, the negative pressure ("vacuum") draws them closed so all the air is drawn through the fan.... most effective when the entire radiator is fully backed by a shroud:

 

The more I think about it, I think keeping the mechanical fan and buying a shroud would be best. The mechanical fan cools fine when the truck is at least moving.


What shroud do I need? JBG lists one but the dimensions are different than what I had measured. From the holes already in my radiator it comes out to be around 28x20.


Can anyone point me in the right direction on which one to get?

 

I run this with a two speed 19" fan off of a late 90's lincoln:

I had pretty high temps in traffic so I completely removed my clutch fan and replaced it with the electric one... had it on for two years with the stock alternator and an optima red top. No problems whatsoever with the alternator struggling to keep up. It's easy to wire up and just set the temp that it kicks on with a small screw driver... the higher speed kicks on 10 degrees higher than the low, and it also has a manual override wire which I have on a switch for passes when towing. works great; haven't overheated yet.

 

Hey guys. Reviving this old thread....I picked this up out of a Lincoln town car today while I was at the pick pic n pull. I'll be going back for a 3g alt at some point. Will this be a good fan for a Highboy with a 390? supposedly it's got internal resistor. does this have an internal temperature controller? Is it a 2 speed? Thanks for any info you have on this.

2001 Lincoln Town Car.

 

If it is a two-wire plug then it is typically single-speed.

.. three-wire and it's more than likely a two-speed fan.

I know, fire it up!

 

Here,s what I did No over heating problems Yet.

 

Nice. This is a 3 wire fan. I'm assuming 2 speed. I have no clue how to wire this thing up. I'll look into it when I get the 3g conversion done and I'm ready to give this a shot. I've heard changing the alt isn't that big a deal. Off to the pic n pull again.