Cooling - Flex Fan or Elect Fan

jamjet · May 23, 2007

351 EFI, Shroud, Griffin 4 core alum rad, Mr. Gasket 180 T-stat, stock water pump

Running 160 - 170 at cruz, when at idle in traffic 200 - 210...arizona 100 degree plus days.

Obviously an air flow issue..

Would a flex fan be the ticket?? I have no experience with one. I understand that the 4 core has a lot of surface area and that a 3 core would most likely work better.

I am thinking that an electric fan would be the way to go...I wouldnt think a flex fan would make a that much of a difference?? Seems to be pro and cons of the flex fans from other members.

No cut outs in the hood for airflow which would obvisiouly help.

Thanks

76Broncofromhell · May 23, 2007

Neither, and Search. This is probably the most frequent argument on this site.

SaddleUp · May 23, 2007

If that was the only time it would get warm then 210 wouldn't worry me. If it's getting that hot in traffic at an idle though then it will get hotter on the trails.

I didn't even know there were any 4 core aluminum radiators available. Most are either one or two core. (Mine is a 2 core)

Flex fans usually don't help much. A good fixed pitch fan that is set up properly will work better. Be sure your fan is not too far out of or into the shroud. I think it should be 1/3 to 1/2 of the fan inside the shroud but a search here should give a better estimate (I know it's been discussed here). If all else fails you can try an electric. On mine it did okay in traffic but would overheat at slow trail speeds. As soon as I took it down the road at 20 or so it would cool back down. My solution was to put a Taurus electric fan in but it wasn't a simple swap. I had to cut and rebuild the core support to allow the radiator to be moved forward and down about 2". Now it does great in town and crawling around on the trails (Seldom gets over 200 on the trails) but will run a little warm (210 or so) at 70 MPH on the freeway. It's the same problem except that now the fan blocks too much air at freeway speeds. I can live with that though since it cools down fast as soon as I slow to 45 or 50. Note: It got warmer initially on the freeway until I bypassed the thermal switch and left it on all of the time. If it's turning it's moving more air through it.

iwlbcnu · May 23, 2007

The main reason to avoid flex fans is in case you ever hit water, they will flex right into the rad.
BUT, if you get the good flex fans, not the cheapy, they do move alot of air.

Mark · May 23, 2007

210* for a 351 is not bad

DRBRONCO69 · May 23, 2007

If you are running 200-210 on a 100 degree day with a 351, you have no cooling problem at all. If you are really worried about it, you can install an additional pusher fan (elec). I wouldn't worry about it at all and I am sure others will agree. Just my .02.

JWMcCrary · May 23, 2007

76Broncofromhell said:
Neither, and Search. This is probably the most frequent argument on this site.

Thank you so much for providing such a warm welcome to new members.

Skiddy · May 23, 2007

Mark Troy said:
210* for a 351 is not bad

Yep considering an efi runs a 195 t-stat

Scrapper_MV · May 23, 2007

What manifold do you have?

This might help.

http://classicbroncos.com/manifold_cooling.shtml

jamjet · May 23, 2007

Thanks for all the suggestions
What is a "high temp" for the 351?
If it his hitting 210 in traffic (idle) my concern is on the trail...its only going to get hotter.

Saddle I thought it was a 4 core I'll check again..although I wont be home for a couple of weeks. I did find info on fan depth when I did a search here..the fan sits 1/2 in the shroud. Were you able to slip the Taurus fan in between the grill and rad? I have looked at some of the fans and it seems as though the grill might have to come off for the fan install.

Not sure as to which manifold I have.....

Skiddy · May 23, 2007

jamjet said:
Were you able to slip the Taurus fan in between the grill and rad?

I have the same setup as saddleup and you will have to move your radiator out about 2". btw it is a puller so you have to mount it between the engine and rad.

iwlbcnu · May 23, 2007

The taurus fan goes behind the rad requireing mods to push the rad forward into the grill, requiring the use of hood pins also, pretty indepth. OR switching over to an Explorer serpetine belt setup.
Since you are cooling good at speed, shows the fan needs work.

jamjet · May 23, 2007

So your not running an engine mount fan?
I was thinking of adding a fan to the front of the rad on a thermal switch.
Sorry for my ignorance....How would the serp set up help? , To move the rad forward you have to open up the core support to a size that will allow the rad to slip into??
Thanks

Skiddy · May 23, 2007

no engine fan just electric. The exploder serp. set up is shorter than the mustangs and gives you more room. Sounds like you have the v-belt still? To install the fan you will have to cut out around your core support bout the size of your rad. and move it out, i used 2x2 angle and welded it back in. There are some pusher fans out there that would help while sitting,crawling but not sure which ones also have heard people say that it restrics air flow by having another fan with the mechanical one. My brother has both but he has a full size and not near the air and space restrictions that we do.

jamjet · May 23, 2007

Thanks Skiddy

Still curious as to what temp is "hot".....red line so to speak

JWMcCrary · May 23, 2007

If your running a v-belt setup might think about BC Broncos water pump pulley. I added it to mine and it definately helps.

Skiddy · May 23, 2007

jamjet said:
Thanks Skiddy

Still curious as to what temp is "hot".....red line so to speak

on mine 302 though I have ran it up to 215-220 before I started having any problems, I had it up to 230

and it did not like it. This was before I put in my tauras fan.

jamjet · May 23, 2007

It is a V -belt setup. I figured this was an airflow problem...thought about a pump and pulley but I didnt think it would help. Did you have the same symptoms?

JWMcCrary · May 23, 2007

My symtoms were about the same. I added a pusher fan on a thermostat and it helped. Since I added the BC pulley the pusher has yet to come on. I haven't been offroad...but it has run a lot in stop and go traffic with no problems at all.

I think some of my problems were that my engine just wasn't broken in enough. If your engine is new that may be part of your problem.

JWMcCrary · May 23, 2007

Not to sound like a ad for the BC pulley...but..you can put your hand back around the carb with it idling and you can feel the fan pulling air...it didn't do that before. I'm running the stock 7 blade fan.

Cooling - Flex Fan or Elect Fan

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