[torqhead]

As has been pointed out, and I agree with, the motor is not overheating and cooling fine. I believe in doing things right but at the same time using the "KISS" theory. It's not necessary to make a mountain out of a mole hill.

Andrew, if you want to pull all of that apart that's up to you but I don't think you'll gain much of anything. Your time would probably be better spent working on something else but that's up to you. The only issue I was pointing out is the sensor in that position isn't correct.

Cliff, my good friend, you get validated more every day!

[Formulajones]

Originally Posted by andrewT

Ya I know those probes. This champion rad came with nothing but a rad. And ya I'm not about to put a bunch of metal shavings into the rad.
Looks like water crossover will be getting a sensor and I'm going to pull apart my water pump

I'd hold off on the water pump deal and save yourself some work at least for now. I'd just move the fan switch to the engine as I suggested early on (water cross over works fine) and eliminate all the wonky possibilities that putting it in the radiator presents, and then drive the car and see how things act before coming to the conclusion you have any type of overheat issues.

Like I said before, I've been experimenting with this lately, and had the sensor mounted in the bottom of the radiator on the hot side where it would never be uncovered with coolant, and it just didn't like it when the car was in motion.
Worked perfectly sitting in the garage and idling for 30 minutes and watching the fans kick on at 185, off at 175 where we had the rheostat set, and it would pull the engine down to 175 in 30 seconds. I'd watch this cycle go on several times without a hiccup. But out on the road when the car was moving the fans wouldn't kick on until the engine reached 195 degrees and then struggled to pull it down, temp creep started making my dad nervous. I surmised that all the air moving across the radiator was doing funky things with the sensor. I ended up turning the rheostat down all the way and forcing the fans to run continually until we got home, which resulted in the engine staying around 185. But shouldn't have to do this, fans won't last long like this.
So I decided to move the fan switch to the engine at the water cross over. So far now, while driving, the fans kick on and off as they are supposed to and it has done a good job at keeping the engine around 185 while driving. My only issue is I'd like to see the fans not kick on at all, or very little, while moving down the road at 50+ mph but there just doesn't seem to be enough radiator to do so at the moment. Once heat soak sets in on an hour long drive the fans have a hard time pulling the engine down below 185 and it just stays in that range. Once stopped and idling, it will cool back down. Opening up the shroud for more airflow while the car is moving has seemed to help this some but I think more is needed or maybe a change in design. But in a nutshell, moving the sensor to the engine definitely helped the scenario.

["QUICK-SILVER"]

Originally Posted by andrewT

I am sure the gauge is fine as I can feel the car behaving differently when its hot but will try another gauge to make sure.

Different how?
One member said it was fine and you wasn't experiencing any problems.

I/We DK, so you need to tell us.

Originally Posted by andrewT

yesterday went for a little 30 minute romp. Wired the fans to keep them on the entire drive. Water temps never got over 210, and oil only hit about 230 towards the end of the drive

Fans on full time and cooling "system" up to par....Coolant temps should have been the same as thermostat opening temp.

230°F~240°F oil temps are fine for the VR-1. Need 220°F to keep water out of the oil. That's water from normal combustion process. Past 260°F the oil gets to thin and breaks down fast.

If you're seeing a big oil pressure drop at those temps...It's time for thicker oil.
If oil pressure stays the same...Might consider running a thinner oil.
And what you've got might be just right.

Clay

[torqhead]

Originally Posted by Formulajones

I'd hold off on the water pump deal and save yourself some work at least for now. I'd just move the fan switch to the engine as I suggested early on (water cross over works fine) and eliminate all the wonky possibilities that putting it in the radiator presents, and then drive the car and see how things act before coming to the conclusion you have any type of overheat issues.

Like I said before, I've been experimenting with this lately, and had the sensor mounted in the bottom of the radiator on the hot side where it would never be uncovered with coolant, and it just didn't like it when the car was in motion.
Worked perfectly sitting in the garage and idling for 30 minutes and watching the fans kick on at 185, off at 175 where we had the rheostat set, and it would pull the engine down to 175 in 30 seconds. I'd watch this cycle go on several times without a hiccup. But out on the road when the car was moving the fans wouldn't kick on until the engine reached 195 degrees and then struggled to pull it down, temp creep started making my dad nervous. I surmised that all the air moving across the radiator was doing funky things with the sensor. I ended up turning the rheostat down all the way and forcing the fans to run continually until we got home, which resulted in the engine staying around 185. But shouldn't have to do this, fans won't last long like this.
So I decided to move the fan switch to the engine at the water cross over. So far now, while driving, the fans kick on and off as they are supposed to and it has done a good job at keeping the engine around 185 while driving. My only issue is I'd like to see the fans not kick on at all, or very little, while moving down the road at 50+ mph but there just doesn't seem to be enough radiator to do so at the moment. Once heat soak sets in on an hour long drive the fans have a hard time pulling the engine down below 185 and it just stays in that range. Once stopped and idling, it will cool back down. Opening up the shroud for more airflow while the car is moving has seemed to help this some but I think more is needed or maybe a change in design. But in a nutshell, moving the sensor to the engine definitely helped the scenario.

Hey Larry, that's an interesting issue you're describing with your dads car. The only time I've ever had cooling issues with my 69 GTO is when I rescued it from going to the junk yard and rebuilt the car back in '86. I didn't know it at the time when I got it, but the original short block was cracked from front to back along the mains. After replacing the block and reassembly of the car I had repeated problems with overheating trying to figure out what was wrong (this is in Texas heat). During the process of trying to fix it I had a 5 core (upgraded from stock 4 core) built for it and still was struggling with overheating especially when I ran it at highway speeds, etc. Had to let it sit to cool off. One day, sitting on the side of the road, guy stops to check on me and I'm whining about my cooling issue. True story, he said, "Is the plate installed behind the water pump?". At the time I didn't know what he was talking about as there wasn't one there when I tore the motor apart and I didn't know a lot about Pontiac motors then... Told him there was no plate when I got it. Low and behold, found a plate and installed it and needless to say had to up my thermostat to get the car to warm up properly. lol Someone had changed that water pump and threw that plate over their shoulder, overheating problems started and they just ran that damn thing until it ceased!

Anyhow, back to the regular scheduled program. I ran that setup for 25+ years and 2-3 years ago swapped in a 4 core aluminum from champion when I put the A/C back on the car. I, like others, know heat is one of the worst things for a motor and have always ensured I had plenty of cooling capacity. I think you mentioned it previously, what radiator is Larry Sr. running now? I have no issues with cooling and most if not all of the time the flex-a-lites come on at low speed, only time they run at high speed is when I turn the A/C on which is determined by a sense lead at the control module.

[70GS455]

Originally Posted by geeteeohguy

I'll be the first one here to say that there isn't an overheating problem if the coolant is at 200 degrees. The engine is not boiling over per the OP, is not showing any symptoms of overheating, but 200 degrees is seen as an overheat condition. It isn't. 235-240 is. Not 200. The oil temp seems a bit high, though...........

For the past 40 years, I've driven several Pontiacs running 200-215 degrees for 100's of thousands of miles without issue. Sometimes they ran 180-190, on hot days over a lot of ground, hotter. No overheating, though.

It is an overheating problem if the OP has installed a 180 thermostat. The cooling system does not have sufficient cooling capacity and has lost control of the ability to maintain coolant set point plain and simple.

Now if a 200 thermostat is in place then I would agree, the system is performing as intended.

Sent from my SM-T817V using Tapatalk

[geeteeohguy]

Originally Posted by 70GS455

It is an overheating problem if the OP has installed a 180 thermostat. The cooling system does not have sufficient cooling capacity and has lost control of the ability to maintain coolant set point plain and simple.

Now if a 200 thermostat is in place then I would agree, the system is performing as intended.

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200 degrees is not overheating, plain and simple.

[JLMounce]

Originally Posted by geeteeohguy

200 degrees is not overheating, plain and simple.

Originally Posted by 70GS455

It is an overheating problem if the OP has installed a 180 thermostat. The cooling system does not have sufficient cooling capacity and has lost control of the ability to maintain coolant set point plain and simple.

Now if a 200 thermostat is in place then I would agree, the system is performing as intended.

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This is semantics. No, 200 isn't overheating, but 70gs455 isn't wrong either, if the intended operating temp is 180, the system isn't cooling well enough to run as intended.

That also means if it already can't run at that temperature, pushing the car much harder may result in an actual overheat situation.

[Formulajones]

Originally Posted by torqhead

Hey Larry, that's an interesting issue you're describing with your dads car. The only time I've ever had cooling issues with my 69 GTO is when I rescued it from going to the junk yard and rebuilt the car back in '86. I didn't know it at the time when I got it, but the original short block was cracked from front to back along the mains. After replacing the block and reassembly of the car I had repeated problems with overheating trying to figure out what was wrong (this is in Texas heat). During the process of trying to fix it I had a 5 core (upgraded from stock 4 core) built for it and still was struggling with overheating especially when I ran it at highway speeds, etc. Had to let it sit to cool off. One day, sitting on the side of the road, guy stops to check on me and I'm whining about my cooling issue. True story, he said, "Is the plate installed behind the water pump?". At the time I didn't know what he was talking about as there wasn't one there when I tore the motor apart and I didn't know a lot about Pontiac motors then... Told him there was no plate when I got it. Low and behold, found a plate and installed it and needless to say had to up my thermostat to get the car to warm up properly. lol Someone had changed that water pump and threw that plate over their shoulder, overheating problems started and they just ran that damn thing until it ceased!

Anyhow, back to the regular scheduled program. I ran that setup for 25+ years and 2-3 years ago swapped in a 4 core aluminum from champion when I put the A/C back on the car. I, like others, know heat is one of the worst things for a motor and have always ensured I had plenty of cooling capacity. I think you mentioned it previously, what radiator is Larry Sr. running now? I have no issues with cooling and most if not all of the time the flex-a-lites come on at low speed, only time they run at high speed is when I turn the A/C on which is determined by a sense lead at the control module.

He used to run a 25 year old 4 core copper radiator with the stock clutch fan and shroud setup, and that worked fine. The car never overheats. He decided recently he wanted to try electric fans and a different radiator to clean up the engine bay and free up some HP. So he went with a Cold Case 2 core aluminum with 1 1/4" tubes, and their dual electric fan setup that comes completely enclosed in an aluminum shroud. Had troubles as first at cruise speeds until he moved the controller onto the engine. That seems to have stabilized the temps, however the fans tend to run more than I think they should when cruising along. Tells me either the radiator isn't up to the task or the aluminum shroud is blocking too much air flow. Cutting openings in the shroud with rubber flaps seems to have helped some. More drive time and more experimenting is needed.

[Formulajones]

Originally Posted by JLMounce

This is semantics. No, 200 isn't overheating, but 70gs455 isn't wrong either, if the intended operating temp is 180, the system isn't cooling well enough to run as intended.

That also means if it already can't run at that temperature, pushing the car much harder may result in an actual overheat situation.

Agree with Jason. If there is a 180 stat in the engine and it's running 200 degrees, then there is something going on that is keeping the engine from running at or near the thermostat rating.

Could be a whole bunch of reasons why, but technically if everything is happy and working properly, you can make an engine run at any temp thermostat you care to install.

[Big Bear]

Swapped the copper core rad in my TA for a Cold Case aluminum hoping for better cooling on the highway or in traffic with the AC on. Ended up gaining heat faster and having to use heater to control it from over heating. Noticed coolant leaking from the overflow tube below the rad cap. The aluminum tube is smaller diameter and the original hose didnt fit tight so it leaked coolant and also sucked in air on recovery. I did hear a gurgling sound. Changed to a heavy wall hose to seal better and after a couple of heat cool cycles and the air is out of the system it stays at 180.

[krisr]

Originally Posted by Formulajones

Agree with Jason. If there is a 180 stat in the engine and it's running 200 degrees, then there is something going on that is keeping the engine from running at or near the thermostat rating.

Could be a whole bunch of reasons why, but technically if everything is happy and working properly, you can make an engine run at any temp thermostat you care to install.

It MASSIVELY depends on when the thermostat actually opens. I'm yet to see one open fully open at it's "rated" temperature. New cars have 180F/84C thermostats but don't kick the fans on until 200F+ and they have WAY more cooling capacity than they know what to do with. In my 400, I run a 160F thermostat because it's not fully open until 180F, but I choose not to turn the fans on until 190F, I actually need to turn the fans on around 200F now since switching to E85 (with a half filled block and oil cooler).

OP: Check your fuel pump divider, move your fan switch to the water crossover - not the radiator, see how it drives then. From what you're describing, it doesn't sound too dire and it just needs tweaking.

[torqhead]

Originally Posted by Formulajones

" you can make an engine run at any temp thermostat you care to install."

That's how you say it... dang...

[Formulajones]

Originally Posted by krisr

It MASSIVELY depends on when the thermostat actually opens. I'm yet to see one open fully open at it's "rated" temperature. New cars have 180F/84C thermostats but don't kick the fans on until 200F+ and they have WAY more cooling capacity than they know what to do with. In my 400, I run a 160F thermostat because it's not fully open until 180F, but I choose not to turn the fans on until 190F, I actually need to turn the fans on around 200F now since switching to E85 (with a half filled block and oil cooler).

OP: Check your fuel pump divider, move your fan switch to the water crossover - not the radiator, see how it drives then. From what you're describing, it doesn't sound too dire and it just needs tweaking.

Did a bunch of testing on that years back both on the stove top and on the road. If you stick a thermostat in a pot of hot water along with a temp probe it's actually pretty interesting. In reality every single thermostat I tested actually starts to open a few degrees before it's rated temp, and is fully open a few degrees after it's rated temp.
The 160, 170, and the 180 I tested all behaved nearly identical. For example the 160 actually started to open around 158, and around 162 it was beyond half way, at which point it's open enough to cool the car. It reaches full open at 165. The car I have this in actually will fluctuate 158 to 162 on the gauge on a cold day, because the stat is actually cycling, and as it just cracks open the temp will drop to 158 and close, then back open again. You can watch this as it goes down the road.
Done some of this testing in computer controlled cars with HPtuners hooked up on gauge display while driving. With a 170 stat in that car it would force it to run right above at 172-173 degrees as long as I was moving. On a cold day it would run 167-168 and move up and down between 167 and 173. This stat was never fully open at 173 either, it just happened to be open enough to keep the engine cool. On a hot day the car would run 178-179 while moving. So I didn't program the fans to come on in that car until 190 and off at 185.
Bottom line, from what I've found, the stats don't have to be fully open to cool the engine, especially if the cooling system is up to the task. If you have a 160 stat that doesn't fully open until 180, I'd personally be swapping it for another as that is way out of range from the testing I've done.

[Formulajones]

Originally Posted by torqhead

That's how you say it... dang...

lol

I agree with your statements, no such thing as too much cooling capacity. If I still have your email I'll shoot you some pictures of his setup. I kind of want to change a couple things around but for now it's working for him, I just think it could be better.
Comparing his to my chevelle for instance, (the 2 cars making the most power) His engine is much larger and making a good 100hp more than me. But my cooling setup isn't fancy. With 600hp/tq I also run a 4.10 gear and routinely buzz this thing at 3,000 to 3400 rpm down the highway for extended periods. Yet the engine never gets above 175 degrees and cools right back down to 165 when at a slow cruise. I mean it just never even gets close to hot. Just a simple Griffin radiator with a stock shroud and clutch fan.
That Cold Case radiator looks like a nice piece, similar fin count, same amount of rows and same size tubes. Physically they are identical too, both cars being A-bodies. I can't see any quality differences in it compared to my Griffin. So his shouldn't run all that much hotter than mine in theory. I lean towards the fan setup or shroud as something that might need improvement.

[torqhead]

Originally Posted by Formulajones

I lean towards the fan setup or shroud as something that might need improvement.

Based on what you said I would be leaning this way too, the shroud sounds suspicious to me. When the car is moving 40/50 mph I would think that alone should be enough air movement to cool it without fans running if the cooling capacity is sufficient. I probably could have gone with just the 3 core aluminum, but decided to spend a little extra and get the 4 core just for the simple fact to have more cooling capacity if needed. It's a little extra water/weight but I've got plenty of power so not an issue.

I've got the dual flex-a-lite fan and in the shroud they already had two "rubber flaps" that will open as air is pushed through the areas that the fan blades don't cover. Years ago when I first made the switch from stock factory to electric I had the same challenge with cooling, the stock just worked better. In the mid 90's my factory shroud got trashed (long story) and decided to give the electric's a shot again and ended up with the flex-a-lite setup. Actually ran cooler and has worked flawlessly except for one of the fan motors died last year, so just replaced the whole assembly with a new one as I figured I got a good 25 years out of it!

[Formulajones]

Originally Posted by torqhead

Based on what you said I would be leaning this way too, the shroud sounds suspicious to me. When the car is moving 40/50 mph I would think that alone should be enough air movement to cool it without fans running if the cooling capacity is sufficient. I probably could have gone with just the 3 core aluminum, but decided to spend a little extra and get the 4 core just for the simple fact to have more cooling capacity if needed. It's a little extra water/weight but I've got plenty of power so not an issue.

I've got the dual flex-a-lite fan and in the shroud they already had two "rubber flaps" that will open as air is pushed through the areas that the fan blades don't cover. Years ago when I first made the switch from stock factory to electric I had the same challenge with cooling, the stock just worked better. In the mid 90's my factory shroud got trashed (long story) and decided to give the electric's a shot again and ended up with the flex-a-lite setup. Actually ran cooler and has worked flawlessly except for one of the fan motors died last year, so just replaced the whole assembly with a new one as I figured I got a good 25 years out of it!

Your fan setup sounds nice. This dual setup from Cold Case had nothing to let air through except the fans themselves and that didn't seem to be enough, coupled with the very boxy shroud that is basically up against the core, the air struggles to get through.

[Steve C.]

Stated- "When the car is moving 40/50 mph I would think that alone should be enough air movement to cool it without fans running if the cooling capacity is sufficient."

I can confirm that. I use a Ron Davis Racing Products aluminium radiator/electric fan assembly in conjunction with a Meziere water pump. The dual fans are wired to cycle on and off as necessary and cruising down the road more often than not the fans do not come on. To confirm this I also have a separate switch that controls power to the fans, at highway speed I can turn them off and the temp stays the same. (typically around 180-185 degrees)


.

[70GS455]

Originally Posted by geeteeohguy

200 degrees is not overheating, plain and simple.

If the cooling system will not maintain desired setpoint, it does not have sufficient cooling capacity.

Sent from my SM-T817V using Tapatalk

[70GS455]

Originally Posted by krisr

It MASSIVELY depends on when the thermostat actually opens. I'm yet to see one open fully open at it's "rated" temperature. New cars have 180F/84C thermostats but don't kick the fans on until 200F+ and they have WAY more cooling capacity than they know what to do with. In my 400, I run a 160F thermostat because it's not fully open until 180F, but I choose not to turn the fans on until 190F, I actually need to turn the fans on around 200F now since switching to E85 (with a half filled block and oil cooler).

OP: Check your fuel pump divider, move your fan switch to the water crossover - not the radiator, see how it drives then. From what you're describing, it doesn't sound too dire and it just needs tweaking.

No it does not depend on where it opens closes etc. The number stamped on the box is the coolant temperature set point that the thermostat is designed to regulate to. If the cooling system has sufficient or excess cooling capacity, the coolant will run at the rated temp, within measuring and tstat manufacturing accuracies.

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[Formulajones]

Originally Posted by Steve C.

Stated- "When the car is moving 40/50 mph I would think that alone should be enough air movement to cool it without fans running if the cooling capacity is sufficient."

I can confirm that. I use a Ron Davis Racing Products aluminium radiator/electric fan assembly in conjunction with a Meziere water pump. The dual fans are wired to cycle on and off as necessary and cruising down the road more often than not the fans do not come on. To confirm this I also have a separate switch that controls power to the fans, at highway speed I can turn them off and the temp stays the same. (typically around 180-185 degrees)


.

Ron Davis makes excellent cooling systems, and he's local to me.

Still have my email? Can you shoot me a picture of your shroud? I'm curious what Ron did for yours. Everything he does is pretty much a custom deal per car.