V8 Radiator troubleshooting (1 Viewer)

[lonelydriver]

Hey all, I've got am LS swap with champion radiator, and 2 electric spal fans. Was hot day in socal 90+ degrees and figured it's a perfect day to stress test the cooling system. I had a long upward freeway stretch and then a uphill climb into the mountains ( if you're familiar with the area, 2 freeway north and then up the bottom portion of Angeles Crest through Lacanada flintridge)
Long story short the temps kept going up and up, even on the freeway with both fans roaring I was approaching 220+ and climbing... And this is without A/C.... Not gonna fly in so cal.

I know mechanical fans move more air but I thought that at freeway speeds, that fans don't really matter much (and even stop on some cars at freeway speeds) or maybe they do matter at speed?

My main question:
Since even at higher speeds the temps kept going up does this mean I have a radiator issue? Not so much a fan issue?

I am considering the mosley motors radiator for LS swaps, and open to any other suggestions.

 

[MANUCHAO]

Looking at the pic posted up there.. I see you tranny temps are also on the elevated side of things...
That is not going to help your radiator temps...
You running a trans cooler ?
Blow some compressed air between the rad and AC condenser just to rule out any air flow obstruction....
I run (200°F) the same rad, but with a mech fan.... It does get to 220 with the AC on and ambient temps on the 100+°F, but it does come down pretty quick once I crest the mountain...
If addressing any of that does not help out.. I woud def look at the Mosley option...... That will be my next move when the time comes...

 

[lonelydriver]

Hey Manu my champion radiator is the one with the built in trans cooler , so it's run thru that and then I have an additional external cooler in front of the ac condenser.

Likewise once i crest the hill temps came down really quick.. but didn't give me confidence with something like the grape vine or el cajon pass in summer .,

My condenser is pretty clear so don't think anything is blocking it ..

Thanks for the feedback good to see ur considering the mosley rad as well

Looking at the pic posted up there.. I see you tranny temps are also on the elevated side of things...
That is not going to help your radiator temps...
You running a trans cooler ?
Blow some compressed air between the rad and AC condenser just to rule out any air flow obstruction....
I run (200°F) the same rad, but with a mech fan.... It does get to 220 with the AC on and ambient temps on the 100+°F, but it does come down pretty quick once I crest the mountain...
If addressing any of that does not help out.. I woud def look at the Mosley option...... That will be my next move when the time comes...

 

[OSS]

220° F coolant temperature is "normal" for a big engine and well within safe operating temperature range when driving the speed limit over mountains during the summer.

 

[lonelydriver]

220° F coolant temperature is "normal" for a big engine and well within safe operating temperature range when driving the speed limit over mountains during the summer.

I did read that the stock LS's operate at a pretty high temp 220-230ish, fans kick on around 229ish degrees... , but my worry was with both fans running and at a pretty high speed that the temps were still climbing at a rapid pace instead of holding or cooling. i didn't look like the fans/rad had the cooling capacity

 

[EasternYeti]

I was in the same boat with my swap on Colorado mountain grades. I had a dual electric fan setup as well, with the biggest fans I could fit and the temps just wouldn’t stop climbing once it started past 220 unless I pulled off and popped the hood.

After a two year saga of battling temps I ended up going with a mechanical fan out of a 2500 and a custom shroud. It solved all my Temperature woes and it sticks to 190 on the hottest days or steepest slopes

OSS is right, 220 isn’t crazy high - but if it keeps going that’s another thing.

I know i was bent because I paid for the electric fans (as I’m sure you’d be too) but It was a major relief seeing the difference with the mechanical setup

 

[cruisermatt]

what thermostat do you have? That's pretty much what mine did when I was out there in August. Stock rad, Ford fans
The drive though bakersfield/socal etc was brutal without AC.

 

[lonelydriver]

I was in the same boat with my swap on Colorado mountain grades. I had a dual electric fan setup as well, with the biggest fans I could fit and the temps just wouldn’t stop climbing once it started past 220 unless I pulled off and popped the hood.

After a two year saga of battling temps I ended up going with a mechanical fan out of a 2500 and a custom shroud. It solved all my Temperature woes and it sticks to 190 on the hottest days or steepest slopes

OSS is right, 220 isn’t crazy high - but if it keeps going that’s another thing.

I know i was bent because I paid for the electric fans (as I’m sure you’d be too) but It was a major relief seeing the difference with the mechanical setup

So to clarify, same radiator (what radiator do you have?) with mechanical fan fixed climbing temps even at speed? so seems like at speed the fans have a large effect?

 

[lonelydriver]

what thermostat do you have? That's pretty much what mine did when I was out there in August. Stock rad, Ford fans
The drive though bakersfield/socal etc was brutal without AC.

i believe its the stock one, 186 degrees, the coolant starts to really flow around 190ish.

 

[lonelydriver]

so sounds like at higher speeds cooling is still a FAN issue more than radiator , which i had originally thought the fans had minimal impact at speed

 

[cruisermatt]

yes. at speed fans should be making a negligible difference. @EasternYeti is right the 3/4 ton fan moves a lot of air, might be worth it for you. I'm not ready to give up all the room in front of my engine for one yet

 

[EasternYeti]

So to clarify, same radiator (what radiator do you have?) with mechanical fan fixed climbing temps even at speed? so seems like at speed the fans have a large effect?

Exactly, even at speed. I have a “Be Cool Boneyard LS Swap” aluminum unit that I used both with the electric fans and then the mechanical once I switched over.

The airflow between the two is BEYOND a night and day difference. With electrics it was almost a joke, the 2500 unit moves so much air you can feel it push through the gaps between the hood and the fender.

@cruisermatt makes a great point, the shroud is big - and i know some guys don’t leave enough room to accommodate all that apparatus.

I do think it would be worth your effort to make it work, and call it a day. Custom shrouds arn’t hard to come by and it’s straightforward to setup. I can grab some photos of mine when i visit the body shop tomorrow if you want something to reference

 

[dbleon]

I run a Champion on my LS swap with MeCh fan and HD fan clutch in a fiberglass schroud. Tranny cooler is a big B&M’s unit with the radiator cooler bypassed. On the hottest days in AZ Mashing up steep grades it climbs to 210 on my scan gauge. Never seen it really go any higher. This is without Ac

Great suggestions so far. I would also check to make sure your coolant isn’t too rich.

I think the external tranny cooler is the ticket. But as others have said, your temps are within operating range

 

[lonelydriver]

Sounds like my Radiator isn't the issue, and good feedback on the coolant mixture!

 

[MANUCHAO]

I use the pre mixed coolant...
Also, although I don't think it should make a difference at 100°F+ temps I run a 160°F thermostat...
For stop and go traffic it runs at 190°F
Today going up to Victorville it ran at 215°F with AC on, trans was at 170°F
Outside temps were 101°F...
Your scan gauge 2 should give you a trans temp... That's how I read mine...
Like @dbleon I run a B&M 70297...
Fan is switch wired and have only used it in two occasions

Here are the drawings for the shroud I used on the champion radiator...
In case you decide to go with a mechanical fan...
Credit to @JohnCapoccia...

 

[tmxmotorsports]

I use champion radiators on my swaps with 2500hd mechanical fan with custom fan shroud. Do you have the heater bypass fitting in place that will cause some temperature increase. I don't have a pic of the one I use but @cruisermatt may have a pic of the one he made others have used a plastic one.

 

[MANUCHAO]

Steam port routing also comes to mind....

 

[tmxmotorsports]

Steam port routing also comes to mind....

That too

 

[lonelydriver]

All good stuff, @MANUCHAO thanks for the diagrams I'll check those out. Steam port is routed back into the heater hose instead of the upper rad hose, does it make that much of a difference? Was planning to address it soon.
Sounds like ur setup is working great as the 15 north to victorville is definitely a steep hot pass especially today.

@dbleon I will def bypass the built in rad trans cooler, thanks for the tip.


@tmxmotorsports I DO have the heater bypass valve installed it's the one that has the valve that you can open or close(bypass heater plumbing) , and without it my ac wouldn't really get cold...

Looks like I'll be going with the 2500 hd fan and fan shroud on the champion rad.

 

[tmxmotorsports]

Fan shroud is a must