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Did you flush the condenser fins with water when changing the radiator? It might *look* clear, but there could still be small amounts of build-up that prevent airflow to some degree. You're operating in extreme conditions, so even small things can matter.
Where did you source the replacement fans? Are they OEM? Quality could be suspect.
Has it always behaved this way since you've owned it? Did you notice any change or improvement at all when you replaced all cooling system components? Also, what is your anti-freeze to water ratio?
I flushed the condenser with the stuff you use on ac systems then flushed the fins out with water.
The vehicle sat for a couple of years as i was rebuilding everything in it. In the process of getting it back on the road a new water pump, thermostat, hoses , rad and condenser were used. Before i dont remember it getting hot but its been a while.
Originally Posted by Forcefed86
I agree that 230-240 is pretty much the max OEM's run these days so its likely not hurting anything at that level. I wouldn't run mine there or go racing with my temps that high. But it shouldn't melt down or anything.
Might also verify the temps are actually that high. The factory LS location at the head reads hot IMO. Its always been 5-10* more than at the radiator hose on my stuff.
Howe makes some of the best cores out there and you'd have no trouble keeping it down in the 170-180 range with one of those and capable fan(s). Just have to decide if its worth it to ya. Also the new brushless gm fans flow like 3-4x the air as what you run now. One of those would also "fix" your issue.
In my poor guy hotrodder days I used the windshield washer pump and reservoir (filled w tap water) to mist the radiator at stop lights when it would start to get hot. Used tiny spray paint cap nozzles so it didn't run through much water. Worked better than you'd think.
I confirmed the temps via hptuners and a ir gun matched about 5~ of what i was seeing in hp tuners.
Do you have a link to Howe? Ill add it to the list of rads i was looking at replacing it with. and with the replacment brushless fans do they just go in place of the fans in the shroud already or a whole new shroud?
i have the ECP radiator for the auto trans in my 02 WS6. it keeps the temps at 180-185 with a 160 t-stat, PCM tune for the lower fan on/off settings. I did have a problem in the beginning, it would run at 192-198 and was getting air in the system from one of the ports. One of the fittings wasn't tightened down all the way and was leaking a lil bit of coolant around that area. The attached pic shows the fitting that was leaking but i think that radiator is the frostbite one.
Just had to tighten it about a quarter or half a turn and no more leaks and now it runs at 185 in 90+ weather. I did a quick video of the engine bay of my car and you can kinda see the ECP radiator on there. 02 WS6 engine bay
Did you have any issues installing the ECP rad. Thats the one i was thinking about going with due to the price. Did the factory fan shroud and condenser fit with out issue?
The vehicle sat for a couple of years as i was rebuilding everything in it. Before i dont remember it getting hot but its been a while.
Those fans might not be as good as OEM.
Did you replace the fans as part of diagnosing this issue? Or was this just preventative when everything else was done? If the OEM fans are still working, I might try putting those back in just to see if they do any better.
Also, what is your anti-freeze to water ratio? In your climate, you don't need much anti-freeze. I'd run a ratio that's heavy on water, such as 80/20 or 70/30 at most.
I had to tweak it a little bit with the factory fan shroud and air box. With the ECP radiator i couldn't get the air box to sit flush so i just trimmed the bottom side of the fan shroud with a dremel tool and got it to fit.
Did you replace the fans as part of diagnosing this issue? Or was this just preventative when everything else was done? If the OEM fans are still working, I might try putting those back in just to see if they do any better.
Also, what is your anti-freeze to water ratio? In your climate, you don't need much anti-freeze. I'd run a ratio that's heavy on water, such as 80/20 or 70/30 at most.
just preventative. I pretty sure i threw the old shroud away. I should be around a 70/30 mix right now for coolant
Originally Posted by xxxmalosoxxx
I had to tweak it a little bit with the factory fan shroud and air box. With the ECP radiator i couldn't get the air box to sit flush so i just trimmed the bottom side of the fan shroud with a dremel tool and got it to fit.
A brushless fan setup would fix all your issues...you can get some cheap from the scrap yard and control them with a cheap pwm generator off amazon. My swap ran hot with some mishimoto craptacular fans in traffic. Now I can keep the thermostat closed if I wanted too... I have it set so it stays around 210ish and the fans only run for maybe a minute at a time
A brushless fan setup would fix all your issues...you can get some cheap from the scrap yard and control them with a cheap pwm generator off amazon. My swap ran hot with some mishimoto craptacular fans in traffic. Now I can keep the thermostat closed if I wanted too... I have it set so it stays around 210ish and the fans only run for maybe a minute at a time
^ Are you saying that perhaps only one fan has been operating? Have you previously verified that BOTH fans were operating at high speed when the engine was running those high temps?
both fans were running at those high temps but im not sure if it was high speed or not. Thats what prompted me to take my hp tuners out and test the fan controls inside.
im thinking maybe im only getting low speed. From what I'm reading here this is how the factory ls1 system works
Stage 1, both fans low speed through relay 1
Stage 2, both fans high speed. Fan 1 is only relay 1, fan 2 is relay 2 and 3.
So in theory if i command fan 1 both fans should work.
I tried to pull the fan 1 relay and jump the switch side but nothing happens
^ This would make sense. If you were only getting low speed out of both fans, I would expect coolant temps to creep up over time exactly as you have described (and observed) during those ambient conditions. I would continue to explore this before loading the parts cannon with any expensive new radiator or fans.
If ypur fans dont run with realy #1 on then either fan relay #3 is bad or the circuit between relay #3 and fan #2 is faulty.
They are ran in series this way giving you low speed.
If the other relays are activated and both fans are running that is indeed high speed as they are now in parallel.
Last edited by Bbknucks; Aug 10, 2025 at 08:46 PM.
It sounds like my low speed is broke, but my high speed is working fine. Not really gonna solve my overheating issue as my high speed is commanded to come on 5 degrees hotter than my low side(Fan one is set to come on at 185 and fan 2 comes on at 188 in hptuners.).
Im still going to fix the low side cause its broke though.
on the free way it stayed around 200~
when it go to more stop and go traffic 210-220
hottest was 225 and when sitting staring at the logs at shutdown was 221
More reasonable and i think the system is functioning as intended and when its 105+ out its just to hot
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