LS Radiator / Fan Discussion

Oh, if you don't use both speeds and only use high then fan 1 wire will control that and you probably need a heavy duty relay since it will be having to start the high speed from scratch every time. I use both speeds so that high never has to start from a stop, it always goes through low speed first. I just use standard 40-amp relays.

BTW, I'm no wiring guru either, ask my shop mate, NWFLYJ. He was the one who figured the relay setup out for me. I'm just RELAYING what I learned. (Pun intended! I'm hilarious!)

Here's a pic of the fan on my 19x31 radiator.



Looking at it the shroud may actually be too big for a 19x24. Might be perfect for my 19x28 though.

Looks like I could trim that lip off though and gain an inch ona couple sides.

You could. It would leave a gap that would best be filled but there is a small gap on the bottom in stock form that I riveted a piece of aluminum over to cover. The same could be done anywhere.

Im sure I could nigerneer up something.

Grab your favorite beverage and take a loooong look at your rig. Do what ever it takes to get as big of a radiator as you can mounted in there.
I originally ran a 19x21 on a GM 5.7, I had to use the high side of a Taurus fan a lot.
I swapped in a 19x27 and a Volvo fan, same engine and rarely do I need the high speed. Think August and high RPM.
I would also suggest a Taurus or Volvo fan and a full shroud on the biggest core that you can fit.
Shroud I used was something like this. (http://www.summitracing.com/search/brand/summit-racing/part-type/fan-shrouds/fan-shroud-height-in/19-000-in/fan-shroud-width-in/26-000-in)
Pics of a Taurus vs Volvo below.




Packaged in the Jeep like this.

The good part about the Volvo fan is that the fan itself is separate from the shroud. You can take off the factory shroud and make your own. Look for one from late 90's-'00 Volvo S70 with a turbo. I just looked on Rock Auto earlier and they're ~$120. You can find a used one cheaper though. I see them on eBay a lot.

If you prefer the Taurus fan I have one here in the shop I'll sell pretty cheap. I bought it a long time ago, but decided to use a Volvo fan instead.

hokie_yj said:

The good part about the Volvo fan is that the fan itself is separate from the shroud.

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That's cool. There's quite a few used on eBay right now. I doubt I'd trust my expensive engine to a used one, but a new one is probably the way I would go if I was doing it again.

Well the thing I keep running into on this build is I need this to do that....well I cant do that till I got this. ****!! My water pump doesnt have a pulley so waiting on a good pump, also need to get a alt / PS mount and see if thats interfere at all....dont think it will. Im gona have to lean my radiator back pretty good since I re-fabbed and raised the stock frame rails. The rails about 2" below the heater hose input/output on the 5.3L. I could put a wider radiator in but it would only be like 12" tall. Gona have to go narrower and drop it below the rails with a tube guard to keep it safe.

patooyee said:

That's cool. There's quite a few used on eBay right now. I doubt I'd trust my expensive engine to a used one, but a new one is probably the way I would go if I was doing it again.

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Yeah, I plan on buying a new one when I get to that point.

I picked up 3 (or 4?) Volvo fans, including the cool OEM relay pack (mounted right on the factory shroud) for $12/ea at the pull a part.

best thing is, all you need is a leatherman (or whatever multi-tool) to pull the fans. They are easy to get to and get out.

The ones I been seeing the relays were mounted in front of the battery. I did see something that looked different on Ebay though. Might be the ones you got.

Hey guys,

Just after some opinions on my radiator.k
I do feel I'm beating a dead horse trying too make it work, but as we all know funds dry up real quick and sometimes you gota try and make do with what you got for the moment.

Am I dreaming on trying to keep a stock 5.7 Ls1 (Just basic buggy stuff, headers, exhaust, maflass tune etc) cool with an AFCO 18x18x2?
I just put the Ls1 in from a Land Rover 3.9 v8 uke: and the radiator was more then enough for the smaller v8 but now with an actual v8 it doesn't seem to cool real well.

It has a 16" SPAL 2070CFM fan as a puller and the radiator is front mounted, the radiator its self is filthy and needs 5 years of gunk cleaned out of it, but I don't want to spend $80 at the local radiator place to come to the realisation it just isn't up to the task.

The first shake down run was in approx 104*F heat, which I'm not sure in America, but thats a decently hot day down under lol. :****:
I saw temps of 212-230 but that was the most I saw, but in saying that I let it sit idling then turned off too cool down in-between, and I wouldn't say I was beating on it a whole lot to get those temps.
Driving along I saw it come down to around 176*F, but that wasn't beating it, that was just coasting with some air flow really.

The 18x18 is basically the biggest I can fit in the front without changing a lot, and trying to avoid a rear mount above the belt line if I can due to lots of social wheeling (fun/trail riding), but if it comes to it, I guess i'll have to haha.

From my research on here/another forum, I think i really should be looking for something more along the lines of 24x19 if not 31x19 or so? Get as big as I can in there and forget about it.. but ~ funds don't quite allow that at the moment. But if its what I got to do, its what i gota do..

*EDIT after remembering some other things*
How small can the pressure tank be?
I also realised after that shake down run that i only had a 13psi radiator cap, and will upgrade to a 15psi before the next trip
I'm not 100% sure if I bled it properly, so maybe a good bleed could help? (Done some more reading on that)
And it was only water not a 50/50 mix

And since we all love pictures, here's a picture of said buggy and said radiator.

If you got it down to 176* while moving faster, it would seem your fan may not be sufficient while crawling. Might try a bigger CFM fan and a good shroud to ensure the fan is pulling air through the entire radiator.

Ethann said:

The 18x18 is basically the biggest I can fit in the front without changing a lot, and trying to avoid a rear mount above the belt line if I can due to lots of social wheeling (fun/trail riding), but if it comes to it, I guess i'll have to haha.

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If you have room to do so, you can cut the tanks off the side of the radiator, and increase their size. Keep the overall width of the radiator the same, but increase the tank size front to back. It will make a huge difference because you increase the water capacity, which will allows the water to stay in the radiator longer, allowing it more time to cool.

yankster said:

If you got it down to 176* while moving faster, it would seem your fan may not be sufficient while crawling. Might try a bigger CFM fan and a good shroud to ensure the fan is pulling air through the entire radiator.

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Cool thanks! I might look into a higher CFM fan for sure!

fl-krawler said:

If you have room to do so, you can cut the tanks off the side of the radiator, and increase their size. Keep the overall width of the radiator the same, but increase the tank size front to back. It will make a huge difference because you increase the water capacity, which will allows the water to stay in the radiator longer, allowing it more time to cool.

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Thanks for the idea! I think I do have a fair bit of room to play with in that regards. Could be a cheap bandaid for the moment!

Thanks for your replies, I'll give them a go!

It's not just the size of the radiator - make sure it's a dual pass, and a quality unit. The cheap universal ones have been proven not to cool as well as the nicer radiators many times. It has a lot to do with the shape and number of coolant passages.

My radiator is 27.5 x 20 x 3 outside dimensions with the radiator surface 22 x 18.5. I use single 16" Spal puller with a full shroud. If it gets stupid hot out (like 100+) and I'm on the sand really beating the **** out of it, it will get a little warm. For normal usage and trail riding, I've never had a problem. Stock LS1 Ultra4 style trail rig. PRC made it for me and did a beautiful job with the fabrication. It was shipped the same day I ordered it.