Engine gets too hot at idle

[Garf]

I have a stroked 528ci engine making 700 hp in a 1970 F100.  It stays cool when moving at 180 degrees, but sitting at idle the engine temp keeps creeping up.  It's been up to 210 before I've shut it down.

It has a 3 core aluminum champion radiator, high volume Edlebrock mechanical water pump, 17" Derale flex fan with a shroud.  Flex fan is about half in and half out of the shroud which puts it about 2.5-3" from radiator.

Looking for ideas to solve but thinking of 2 13" electric Spal fans that pull 1777 cfm each with shroud to replace the flex fan.  I have a 140 amp alternator.  Each fan draws 24 amps.

Thanks in advance for any advice you're willing to share.

[sixty9cobra]

I have the Spal fans and they do a great job. I also had a champion radiator and it didn't cut it on 464 cu.in. I bought a Summit 3 pass rad and it stays at 180.

[My427stang]

Very rarely is a flex fan a good choice, especially as you make more heat.

Assuming you have the fan spinning 1:1 or faster with pulley sizing, the best fan for keeping them cool I have seen is the Flexalite race fan

https://www.summitracing.com/parts/flx-101584

I am not an electric fan user unless you can use a very effective fan.  Two 13s seems very small to me

[Drew Pojedinec]

When I first started using my engine I had same issue.
Realized the water pump pulley was under driven, getting the correct one helped a lot.

[jayb]

I think Spal electric fans are the only way to go.  I put them on all of my cars, unless they are stock.  If you are cooling OK running down the road, then the radiator should be big enough for the engine.  Put the biggest Spal fans in that you can fit; I've often used one puller and one pusher just to maximize the size of the fans.  No cooling problems here on engines up to 1000 HP in traffic.

[Tommy-T]

I ass-u-me that you have a 385 series motor. They tend to run a little warmer than FE's, but they can really make big power.

A couple of things I've found that really work.
1) I try to run a 5" water pump pulley and a 7" crank pulley. Folks talk about water pump cavitation. It's talk, nothing more.
2) I run 2 11" Spal paddle fans with shrouds. They come as a kit. The paddle fans are noisy but flow a ton of air.

These 2 things along with a 19"X31" aluminum Ebay radiator keep my D4TE 390 block that's been bored to 4.130 and Hardblocked to the water pump holes nice and cool. Plenty of cruising miles at above 100* this past summer.

[Joe-JDC]

Are you still running a heater with lines to the heater core?  If so, then turn the heater on and see if the temperature comes down any.  If it does then you need to speed up the fan or increase the fan size or make sure it is positioned correctly to the radiator and in the shroud properly.  If you are bypassing the heater, then pulley size or speed will be suspect IMO.  Joe-JDC

[My427stang]

I can't argue for or against a big SPAL or OEM if you have room, there are also some towing kits made by I think Flexalite that are huge and made for towing applications that include a shroud that move a TON of air, ame with the Ford and Lincoln factory stuff

However, given my experience in Vegas with 150+ degree pavement temps, I'd be hard pressed to not try 4 bolts and a 60 dollar fan and check pulley ratio before I added hundreds of dollars in changes.

Those fixed fans really made that much difference regularly on Tri-5 Chevies with Rats and small radiators.  I'll also add that what I used to use in th Northeast and what I do in the Midwest just wouldn't cut it at the extremes.

Again, can't argue what ELSE will work, but those curve tip fans are incredibly capable