LS3 / 525 crate motor.... what's a "normal" operating temperature range
06-06-2019, 09:06 PM
#1
LS3 / 525 crate motor.... what's a "normal" operating temperature range I finished my ls3 swap in my 79 Corvette a few months back. Well summer it's here in Louisiana and engine coolant temps are a bit higher with the ac on. Stock gmpp ecm tune, newer dewitts radiator and elec fans.
From what i can tell is most ls motors run comfortably around 200-210. Mine got to 210 while idling the other day (never seen it that high since it's been on the street, usually 204 fans kick on and temp drops) and wouldn't go any higher or lower after about 10 minutes of idling my driveway. No doubt in my mind if i were to get moving the temp would drop.
I've been thinking of upgrading to some spal fans which should help out at idle. Any thoughts? Pics for the fun of it.
Thanks,
Ryan
From what i can tell is most ls motors run comfortably around 200-210. Mine got to 210 while idling the other day (never seen it that high since it's been on the street, usually 204 fans kick on and temp drops) and wouldn't go any higher or lower after about 10 minutes of idling my driveway. No doubt in my mind if i were to get moving the temp would drop.
I've been thinking of upgrading to some spal fans which should help out at idle. Any thoughts? Pics for the fun of it.
Thanks,
Ryan
06-06-2019, 10:03 PM
#2
TECH Senior Member
We have a stock suburban that once warmed up, never wavers from 210. No harm will come as long as it doesn't go up much from that.
06-07-2019, 08:11 AM
#3
What temp t'stat? What are the programmed parameters for fan on/fan off temps? If your system is designed to control temps at 190F and it's reaching 210F at idle - then something's amiss.
On the other hand, suspect you've got a 187F OEM t'stat and the system is doing exactly what it was programmed to do. But without knowing what it's trying to do, there's no way to tell whether things are working as they should or not.
On the other hand, suspect you've got a 187F OEM t'stat and the system is doing exactly what it was programmed to do. But without knowing what it's trying to do, there's no way to tell whether things are working as they should or not.
Last edited by Michael Yount; 10-13-2019 at 07:44 AM.
06-07-2019, 09:00 PM
#4
My stock 2015 Silverado 6.2 is always at 210 degrees no matter what. My 98 Wrangler LS6 swap with a 187 degree thermostat will run right at that temp most days. Not today it's 92 here in sunny MN. ECM controlled Spal 16" fan kicks in at 205 and turns off at 195. Has worked like a champ for over 10 years. My 68 C10 has a big Afco cross flow radiator 180 degree stat and runs right on that temp. If I let it idle after driving it for a while the fan 16" Spal will kick in at 205 and out at 195.
My.02 is that you are good. With anti freeze mix you have 40 degrees before I'd be really be concerned. Hard to keep your eye off the temp gauge isn't it?
My.02 is that you are good. With anti freeze mix you have 40 degrees before I'd be really be concerned. Hard to keep your eye off the temp gauge isn't it?
06-08-2019, 04:09 PM
#5
TECH Senior Member
iTrader: (7)
If you are using the GMPP harness and ECU, the fan is programmed to come on at 212 and off at 205...as I recall. Sounds like your temperatures are "normal" if you have a stock thermostat.
Andrew
Andrew
06-08-2019, 09:24 PM
#7
TECH Senior Member
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06-08-2019, 10:18 PM
#8
Rick - If the gauge is bone stock too, it likely has a ton of hysteresis built in to keep the gauge from moving around and freaking out the average driver. When you’re going down the highway the t’stat is in charge and actual temps are likely lower - 195F-198F range. In the same year Corvette, when in traffic the fans are in charge and the E38 ecu allows temps in the 220-230F range with the fans. And through all that, the newer gauges never move...210F - all’s well!
They seemed to start that in the mid-late 80's. I first noticed it on the stock fox body 5.0L's in the Stangs. Until you actually overheated them, the gauge just sat right in the middle - never moved.
They seemed to start that in the mid-late 80's. I first noticed it on the stock fox body 5.0L's in the Stangs. Until you actually overheated them, the gauge just sat right in the middle - never moved.
Last edited by Michael Yount; 06-08-2019 at 10:49 PM.
06-09-2019, 02:48 PM
#9
TECH Senior Member
iTrader: (7)
Rick - If the gauge is bone stock too, it likely has a ton of hysteresis built in to keep the gauge from moving around and freaking out the average driver. When you’re going down the highway the t’stat is in charge and actual temps are likely lower - 195F-198F range. In the same year Corvette, when in traffic the fans are in charge and the E38 ecu allows temps in the 220-230F range with the fans. And through all that, the newer gauges never move...210F - all’s well!
They seemed to start that in the mid-late 80's. I first noticed it on the stock fox body 5.0L's in the Stangs. Until you actually overheated them, the gauge just sat right in the middle - never moved.
They seemed to start that in the mid-late 80's. I first noticed it on the stock fox body 5.0L's in the Stangs. Until you actually overheated them, the gauge just sat right in the middle - never moved.
Andrew
06-09-2019, 02:53 PM
#10
TECH Senior Member
Ford temp gauges had three positions- cold, normal, and totally fried. Oil pressure similar- none, normal, and filter explosion.
06-09-2019, 07:17 PM
#12
TECH Senior Member
06-14-2019, 01:19 AM
#13
On The Tree
Nice looking Corvette !!!
I agree with the consensus, and for me using a scan tool is where I start. The gauges are "tuned" to stay put and move slow in the normal operating range as stated before, that is where the scan tool come in "trust but verify"
I agree with the consensus, and for me using a scan tool is where I start. The gauges are "tuned" to stay put and move slow in the normal operating range as stated before, that is where the scan tool come in "trust but verify"
06-16-2019, 11:47 AM
#15
TECH Enthusiast
A other good test for airflow and radiator airflow is when hot roll down your windows & fully turn on heater & blower motor. If temps drop in a few minutes, definitely room for improvement.
07-08-2019, 10:19 AM
#16
well new spal fans are on and it still slowly climbs up to 226. Once I start moving the temps drop, same for if I open the hood. If I turn ac off it'll drop down to around 217-219 which I'm ok with. Turn ac back on and it start climbing back up. I'm comparing temp readings between my autometer gauge and bluetooth torque app. I know engine bay temps are extreme, my intake air temps have gotten up to 206 just sitting, once I get going down the road they're about ambient or about 10 plus.
AC question, I have a line from the evap inside the car freezing up a little (classic auto air unit), I just need to bring it back to have them check service the system. Would being low or high cause the compressor to run harder and engine or engine bay temps rise?
Looks like my only other options are to refill coolant system and to make sure there aren't any air pockets (I filled with a vacuum/purge tool and have been running the car w/out ac for a few months already so I doubt it's this), vent my hood or engine bay, or go spend some more money on a larger cored radiator.
Is there anything else I could be missing?
Thanks for the replies and advice so far.
Ryan
AC question, I have a line from the evap inside the car freezing up a little (classic auto air unit), I just need to bring it back to have them check service the system. Would being low or high cause the compressor to run harder and engine or engine bay temps rise?
Looks like my only other options are to refill coolant system and to make sure there aren't any air pockets (I filled with a vacuum/purge tool and have been running the car w/out ac for a few months already so I doubt it's this), vent my hood or engine bay, or go spend some more money on a larger cored radiator.
Is there anything else I could be missing?
Thanks for the replies and advice so far.
Ryan
07-10-2019, 07:20 PM
#18
Blueday - if temps keep climbing with fans on, but drop when you start moving - then the fans aren't moving enough air to reject enough heat to keep the temp at your control point.
A note about more (thicker) core. You get pretty diminished returns by adding more rows after the first two. As air moves across the first row, it picks up heat from the first row. So the air temp when it hits the next row is significantly higher -- so there's less delta-T to remove heat from the second row, even less for the third, rinse/repeat. If you double the number of square inches of core (L x W) - you double the amount of heat rejection capability - 100% more capability. When you keep L x W the same, and add a second row, you only get about 50% more heat rejection capability. The third row only adds about 15% more capability. Additionally, there's more restriction to air flow across the core the more rows you have. So those same fans may have even bigger problems moving the same amount of air across more rows.
If you determine you need more heat rejection capability, more L x W works better. Given, however, that temps drop when you start moving, I think your fan choice is the key to a solution.
A note about more (thicker) core. You get pretty diminished returns by adding more rows after the first two. As air moves across the first row, it picks up heat from the first row. So the air temp when it hits the next row is significantly higher -- so there's less delta-T to remove heat from the second row, even less for the third, rinse/repeat. If you double the number of square inches of core (L x W) - you double the amount of heat rejection capability - 100% more capability. When you keep L x W the same, and add a second row, you only get about 50% more heat rejection capability. The third row only adds about 15% more capability. Additionally, there's more restriction to air flow across the core the more rows you have. So those same fans may have even bigger problems moving the same amount of air across more rows.
If you determine you need more heat rejection capability, more L x W works better. Given, however, that temps drop when you start moving, I think your fan choice is the key to a solution.
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Breezee 87 (08-03-2022)
07-13-2019, 11:20 AM
#20
Blueday - if temps keep climbing with fans on, but drop when you start moving - then the fans aren't moving enough air to reject enough heat to keep the temp at your control point.
A note about more (thicker) core. You get pretty diminished returns by adding more rows after the first two. As air moves across the first row, it picks up heat from the first row. So the air temp when it hits the next row is significantly higher -- so there's less delta-T to remove heat from the second row, even less for the third, rinse/repeat. If you double the number of square inches of core (L x W) - you double the amount of heat rejection capability - 100% more capability. When you keep L x W the same, and add a second row, you only get about 50% more heat rejection capability. The third row only adds about 15% more capability. Additionally, there's more restriction to air flow across the core the more rows you have. So those same fans may have even bigger problems moving the same amount of air across more rows.
If you determine you need more heat rejection capability, more L x W works better. Given, however, that temps drop when you start moving, I think your fan choice is the key to a solution.
A note about more (thicker) core. You get pretty diminished returns by adding more rows after the first two. As air moves across the first row, it picks up heat from the first row. So the air temp when it hits the next row is significantly higher -- so there's less delta-T to remove heat from the second row, even less for the third, rinse/repeat. If you double the number of square inches of core (L x W) - you double the amount of heat rejection capability - 100% more capability. When you keep L x W the same, and add a second row, you only get about 50% more heat rejection capability. The third row only adds about 15% more capability. Additionally, there's more restriction to air flow across the core the more rows you have. So those same fans may have even bigger problems moving the same amount of air across more rows.
If you determine you need more heat rejection capability, more L x W works better. Given, however, that temps drop when you start moving, I think your fan choice is the key to a solution.
I can't get more surface area w/out modifying the core support a lot. I'm running an aluminum 2 row dewitts with 1" tubes right now. I do see that dewitts makes a a 2 row radiator that fits but has 1.25" tubes (flows 1 side to another) . Or another option is that they make a ls swap radiator (2 row w/1" tubes) that has the inlet/outlet on the same side plus steam vent connection. Any thoughts on the thicker tubes helping or the actual ls swap radiator?
Also upon digging ( i think i came across your name michael ) I'm wondering if this is worth looking at......my classic auto air has a heater core block off valve controlled by the ac system so i don't actually have coolant flowing back into the system like it "should". Apparently this is controversial but could my overheating problem be related to this? I think I'm going to go ahead and put a tee in so it'll flow either way similar to your setup michael.
Thanks
Ryan