LS swap coolant temps
 

Good afternoon everyone, I have a mild 6.0 in my 72 with an Entropy LS radiator, new OEM stock t-stat. I have been playing around with my fan set points. Originally, I had it set for the first fan to come on at 180, second at 205. This meant the primary fan ran all of the time. No big deal, it ran right at 193 all of the time, highway and stop and go. Changed them to 206/200 & 215/206 On/Off for the fans. Now that we have gone from March 99th to August 1st here in the Midwest as far as weather, I am noticing that my temp creeps up at stoplights to 208 or so. It never gets hot enough to trigger the second fan. Start moving and it drops back down to 193 as it should. Since under the hood is a giant hot box with the engine and headers, I feel like this is normal, but I felt I should do my due diligence and see what everyone else experiences.

Currently, I have each fan operating independently. I am really leaning towards adding another relay to get high/low on both fans for the sake of noise since these Entropy fans a wicked loud.

What is everyone else seeing with the temps when it's warm outside with stock or close to stock set points?

Re: LS swap coolant temps
 

When they set my fan temps, they put fan 1 on at 175...fan 2 on at 185...my thermostat is a 165..
I pull heavy loads with mine and even in Aug it never gets over 185...
Fan 1 runs all the time...fan 2 turns on and off as needed..
But on the flip side my z71 runs at 215...

Re: LS swap coolant temps
 

I'm running a Single 16" Spal and the fan turns on at 205 and off at 195. I'm running a 180 stat. It runs right at 180 unless I'm moving thru a lot slow traffic.

Re: LS swap coolant temps
 

So it sounds like these temps are reasonable. I may play with wiring both at half speed at a little lower temp.

Re: LS swap coolant temps
 

FWIW...I have 2 fans w/3 relays running both on low then on high once the AC is activated or higher temps. Low on at 195, high on at 205. 187 deg thermo. Im in California and have yet to have the high activate unless the AC is on. I agree the Entropy fans are loud in normal mode, that's why I went with the 3 relay setup as you are considering. I can hardly hear the fans on low speed. Very happy with this setup, as I think you will be also....

Re: LS swap coolant temps
 

You should check to make sure your fans are okay to run in series as not all fans are. I initially had my Spal fans wired up with the 3 relay setup to run in series, then I stumbled on info on the internet saying that Spal fans are not meant to run in series. So I reached out to Spal and they told me the same thing and that it would shorten the life of the motors. Spal fans are single speed fans.

Re: LS swap coolant temps
 

All of you are running a lot cooler than me. I’m using a Holley frostbite radiator with F-body fans. In the summer without the A/C my 5.3 runs between 208-210 and with the A/C on it runs between 218-220. It drives me nuts. I’m about to add an expansion tank as I lose some fluid through the vent. I keep reading these are normal temps for the LS, but I DO NOT like running that warm.

Re: LS swap coolant temps
 

Jesse...I know what you mean..I think we all think about sbc...but the LS runs hotter and it doesnt seem to be a issue..I wouldn't worry about those temps...that's about where my '13 GMC runs...

Re: LS swap coolant temps
 

Thanks everyone! Sounds like my temps are right in line with everyone. A 3-relay setup is definitely in the works.

Re: LS swap coolant temps
 

Now that I got my truck running I see what everyone is saying about the fan noise.

Nick, did you every find out if the 3 relay mod is an issue with the Entropy fans?

Re: LS swap coolant temps
 

I emailed them a while back and they said they had no problem with me wiring them with 3 relays. I have the parts to do it, just haven’t had a chance to wire it up.

Re: LS swap coolant temps
 

I emailed them a while back and they said they had no problem with me wiring them with 3 relays. I have the parts to do it, just haven’t had a chance to wire it up.

Re: LS swap coolant temps
 

i have on fan comes at 190 another is set at 215 which i hate but normal driveing my runs 1aorund 180-190

Re: LS swap coolant temps
 

I ended up lowering mine 4°, both fan 1 and 2, but I haven't had a chance to really get out and drive it to see how it likes it.

Fan 1: 202 on /196 off
Fan 2: 211 on /203 off

Re: LS swap coolant temps
 

So what makes Spal's DC motors any different than any other DC motor? Many different OEM's run their fans in series and I have never heard of any thing detrimental happening to the fan motors by running them half-speed.

Re: LS swap coolant temps
 

I don't know enough about electricity and motors to tell you that. That's just what SPAL told me on the phone.

Re: LS swap coolant temps
 

Made a relay box for the fans and headlights. Been working well, give it a try if you like....

Re: LS swap coolant temps
 

Have you not had the check engine light come on? I have the same diagram for the fans and trinary switch, but with a diode and a resistor on the blue wire out of the trinary switch so the PCM doesn't see an uncommanded ground and turn on the check engine light.

Re: LS swap coolant temps
 

I know you're already answered but I figured I'd chime in for anyone else now that I finally got at least one fan hooked up.

2006 GMC Yukon radiator - 34" core
2006 GMC Yukon dual fans - only one hooked up right now

First fan at 180 (hooked up)
Second fan at 195 (will be hooked up)

Idling in my blacktop driveway, in the sun, in 88 degrees and humid. I let the truck get to around 200 degrees. Connected the one fan I have a relay and harness for, and within 5 minutes it was down around 177 and the fan shut off... revving the engine up brought it down another couple degrees.

Just a stock 5.3. I know no load, not idling in gear, etc... still pretty OK with those temps and that performance.

Re: LS swap coolant temps
 

Hey MDP, I never got around to putting the diode in mine and I have never had a CEL 6 years. So the second truck I did the same and no light yet.
My swaps were genIV e38 ecm’s.

Re: LS swap coolant temps
 

Interesting. I wonder if the Gen 3's are different in that regard.

Re: LS swap coolant temps
 

Would you mind sharing pictures of your radiator setup? I had looked at using the same radiator, but didn't know how to make it fit in the core support being a few inches wider than the stock core. This is assuming you have a 67-72.

Re: LS swap coolant temps
 

I have a 2005 Vintage Air with a trinary switch and factory relay setup. No engine light.

Re: LS swap coolant temps
 

I have a squarebody (1980) but on the squares the only thing I had to remove was the old air intake pass-through that wasn't in use. I'd be happy to send photos if you still think they'd help as long as you promise to ignore my temporary zip tie upper radiator mount :lol:

Re: LS swap coolant temps
 

Well, I am sending my radiator back for the second time (ugh), so while it is gone I thought I would do this mod. I am pretty sure I know the answer to this, but want to confirm that I do not have to do any reprogramming to make this work correct? My set points will stay the same and since it is just providing a ground I cannot see anything I would have to change. Can someone confirm that for me?

2004 LQ4 in case it matters.

Thanks!