Vortec Thermostat Experiment

[AuroraGirl]

Adding flow IS what you want to do if you want the cooling aystems capacity to be increased. My cooling system has to shed nearly twice as much heat as the factory installed 350. I have a high flow pump as well that is more balanced bank to bank. The stock pump is just ugly in flow distribution. While it will get grannys 140 hp 305 wagon to the groccery store and back it has no place on a performance engine. Also my cooling system is new and it is clean. Green coolant will not be going anywhere near it. I ran Nissan Blue for years then with the 383 and new radiator switched to semi truck coolant. Both are far better at protecting aluminum. The semi truck coolant is actually better at transfering heat. It was designed to better withstand high temperatures found in diesels with water cooled EGR coolers. The engine in my 1980 Corvette did not even have a thermostat, just a restrictor ring. The car was never driven in cold weather so it was not a problem to run it that way. The water outlet angle on a Vortec does not trap air and the hose is uphill all the way to the radiator. I use a Lisle burping funnel to purge the cooling system of air.

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the only issue i can see maybe is your coolant. is your coolant you are using, was that put into service while the blocks passages were freshly cleared or not at all corroded or mineral deposits? THe green coolant is abrasive, its how it keeps the system wokring, but you used nissan blue. was nissan blue putting a protective coating or also abrasive? The way dexcool works, if you had a fresh clean system without any solder or brass/copper concerns, it would put a film down which would keep the issue at bay in the service life span. if it was not clean, its got insulating corrosion or minerals that will hinder your cooling

 

[L31MaxExpress]

the only issue i can see maybe is your coolant. is your coolant you are using, was that put into service while the blocks passages were freshly cleared or not at all corroded or mineral deposits? THe green coolant is abrasive, its how it keeps the system wokring, but you used nissan blue. was nissan blue putting a protective coating or also abrasive? The way dexcool works, if you had a fresh clean system without any solder or brass/copper concerns, it would put a film down which would keep the issue at bay in the service life span. if it was not clean, its got insulating corrosion or minerals that will hinder your cooling

Clean fresh build, new radiator, new water pump, new hoses everywhere. Only things re-used were the metal heater hose lines and heater cores and they were well flushed.

My only problem is that I am dumping 2x the heat into the cooling system as the stock engine did. More air and fuel = more heat and a bigger bang = more horsepower. More heat from having a higher compression ratio as well.

 

[AuroraGirl]

Clean fresh build, new radiator, new water pump, new hoses everywhere. Only things re-used were the metal heater hose lines and heater cores and they were well flushed.

My only problem is that I am dumping 2x the heat into the cooling system as the stock engine did. More air and fuel = more heat and a bigger bang = more horsepower. More heat from having a higher compression ratio as well.

thats true yes, did you see what I had said about oil cooling before. does your truck utilize one?

 

[Pinger]

My only problem is that I am dumping 2x the heat into the cooling system as the stock engine did. More air and fuel = more heat and a bigger bang = more horsepower. More heat from having a higher compression ratio as well.

The higher compression ratio is at least trying to help you!
Higher compression ratio also means higher expansion ratio so more energy is being extracted in the cylinder and the exhaust gas leaves the cylinder cooler than it would with a lower compression ratio. Thus, less heat from it is absorbed into the coolant as it passes through the (cooled) exhaust port. Additionally, the smaller combustion chamber with the higher compression ratio also means less surface area to absorb heat into the coolant during the very high temperature combustion event.
All very small contributions in the overall scheme but working with you nonetheless.

 

[L31MaxExpress]

thats true yes, did you see what I had said about oil cooling before. does your truck utilize one?

Yes my engine has an oil temperature stabilization device in the hot side tank of the radiator. As well as its equal for the transmission in the cold side tank. Both work as designed.

 

[ralmo94]

Have you had your block drain plugs out? If not there might be build up in your block passages.

 

[L31MaxExpress]

Have you had your block drain plugs out? If not there might be build up in your block passages.

This engine was built from a bare block. No buildup at all. It does have a street fill of hard block in it. To the bottom of the freeze plugs to help with lower end strength.

I do not know why people keep coming up with the dirty cooling system theory. This is a fresh build with new parts.

That being said the 195F high flow has it running 196-199F moving down the road. After 30 minutes of idling with the ac on in 85°F ambient it had climbed to 203°F. My intention is to put a 180°F high flow in it and send it. I will put the 180°F high flow into it when it gets the intake swap. I will be pulling the metal bypass pipe out of the water pump, tap the pump for a pipe plug and drill the thermostat with two 0.125" holes for a constant bypass as I have always done with Vortec head swaps. It will be using the Edelbrock 180F high flow balanced robert shaw design thermostat when the new intake goes on. Doing this forces the bypass water through the radiator and prevents air and steam pockets from forming while the thermostat is closed.

 

[Schurkey]

There's a misconception that if you have too much flow the coolant doesn't stay in place long enough for the heat to be transferred to it. That's bad science. The heat is going to transfer to whatever coolant the hot surface is in contact with.

Thank you. There's so much misinformation about cooling systems floating around automotive forums. Nice to see truth.

The problem with flow comes when you pump coolant near its boiling point too fast, and the localized drop in pressure on the draw side of the pump causes it to boil. The water pump can't pump vapor, and it cavitates until the coolant cools down, changes back to a liquid, and can be pumped again. You get a temperature spike that can cause detonation.

Technically true, but the "draw" (I'd have said "inlet" or "suction" side) SHOULD be the already-cooled fluid coming directly from the radiator.

Water pumps can cavitate, though. I think it has more to do with impeller speed and inlet restriction rather than inlet temperature.

Similarly, when there's a problem with the lower radiator hose collapsing, most folks say to shove a "spring" inside to "support" the lower hose. I say to check the radiator for restriction. If the lower hose collapses, it's because you're pumping water out of the hose at the water pump end, faster than it can re-fill from the radiator side.

This is why I said you do not want high flow, no thermostat is just asking for cavitation and thus hotspots/boiling. The flow can be restricted without a thermostat, and then you would eliminate my concern. but these are more common on racing where they want to reduce drag and use propylne glycol from what I can tell, , so not spinning the hp on the pump against a thermostat but also cooling sufficiently in a WOT pull situation, from what i gather

Propylene glycol (PG) anti freeze is popular with the Eco-sensitive; I've used it too. Doesn't poison dogs or squirrels who might drink a little out of the coolant drainpan left unattended too long. I figure it's better to appropriately contain 'n' dispose of the waste anti-freeze in a timely manner. But like I said, I've used the stuff and it worked OK. Been a long time...

The PG antifreeze doesn't have to have anything special in the cooling system; it is just a little "thicker" than ethelyne glycol; and doesn't have quite the freeze protection. You'd need a different freeze-protection tester than Ethylene glycol.

https://www.amazon.com/old-world-sep003-antifreeze-coolant-propylene/dp/b000ccm5ja

"High flow" is very welcome...but only when the heat load demands it. The whole point of a thermostat is to choke-off coolant flow to make the cooling system much less efficient, so the engine warms-up quickly and stays at a reasonably-steady temperature. This is why engines operated at idle or cruise should run within a few degrees of the thermostat rated temperature; if the engine is more than 20-ish degrees above the thermostat rating, it's lost control of engine temp. Of course, some of that depends on when the fan(s) are activated--GM often doesn't turn on an electric fan until 220 degrees or so. The second electric fan may not come on until 230. If the cooling system is running way hot at idle or cruise, it's got no reserve capacity for when you're dragging a trailer up the mountain, or other heavy-throttle use. THAT is when the thermostat should be WFO, and the engine coolant temp may climb some.

The "big deal" with having a restrictor in the thermostat housing--either an actual thermostat, or a restrictor disc--comes from the older, top-to-bottom flow radiators. UNLIKE a typical cross-flow radiator, the pressure cap is on the inlet side, ahead of any restriction presented by the coolant tubes in the radiator. Having radiator-cap pressure, PLUS water pump pressure (especially at high water pump speed) that isn't moderated by the restriction, will overpressurize the radiator cap, causing it to release pressure and therefore loss of coolant. Then the system is low on coolant, so the engine overheats.

A cross-flow radiator has the pressure cap on the outlet side, so it maintains cap pressure despite water pump suction, leading to higher overall pressure within the engine. Cross-flow radiators are way better than vertical-flow radiators for this reason. And then GM starts building vertical-flow radiators after decades of cross-flows, for the GMT360/370 Trailblazer/Envoy series of vehicles.

 

[AuroraGirl]

Thank you. There's so much misinformation about cooling systems floating around automotive forums. Nice to see truth.


Technically true, but the "draw" (I'd have said "inlet" or "suction" side) SHOULD be the already-cooled fluid coming directly from the radiator.

Water pumps can cavitate, though. I think it has more to do with impeller speed and inlet restriction rather than inlet temperature.

Similarly, when there's a problem with the lower radiator hose collapsing, most folks say to shove a "spring" inside to "support" the lower hose. I say to check the radiator for restriction. If the lower hose collapses, it's because you're pumping water out of the hose at the water pump end, faster than it can re-fill from the radiator side.


Propylene glycol (PG) anti freeze is popular with the Eco-sensitive; I've used it too. Doesn't poison dogs or squirrels who might drink a little out of the coolant drainpan left unattended too long. I figure it's better to appropriately contain 'n' dispose of the waste anti-freeze in a timely manner. But like I said, I've used the stuff and it worked OK. Been a long time...

The PG antifreeze doesn't have to have anything special in the cooling system; it is just a little "thicker" than ethelyne glycol; and doesn't have quite the freeze protection. You'd need a different freeze-protection tester than Ethylene glycol.

https://www.amazon.com/old-world-sep003-antifreeze-coolant-propylene/dp/b000ccm5ja

"High flow" is very welcome...but only when the heat load demands it. The whole point of a thermostat is to choke-off coolant flow to make the cooling system much less efficient, so the engine warms-up quickly and stays at a reasonably-steady temperature. This is why engines operated at idle or cruise should run within a few degrees of the thermostat rated temperature; if the engine is more than 20-ish degrees above the thermostat rating, it's lost control of engine temp. Of course, some of that depends on when the fan(s) are activated--GM often doesn't turn on an electric fan until 220 degrees or so. The second electric fan may not come on until 230. If the cooling system is running way hot at idle or cruise, it's got no reserve capacity for when you're dragging a trailer up the mountain, or other heavy-throttle use. THAT is when the thermostat should be WFO, and the engine coolant temp may climb some.

The "big deal" with having a restrictor in the thermostat housing--either an actual thermostat, or a restrictor disc--comes from the older, top-to-bottom flow radiators. UNLIKE a typical cross-flow radiator, the pressure cap is on the inlet side, ahead of any restriction presented by the coolant tubes in the radiator. Having radiator-cap pressure, PLUS water pump pressure (especially at high water pump speed) that isn't moderated by the restriction, will overpressurize the radiator cap, causing it to release pressure and therefore loss of coolant. Then the system is low on coolant, so the engine overheats.

A cross-flow radiator has the pressure cap on the outlet side, so it maintains cap pressure MINUS water pump suction, leading to higher overall pressure within the engine. Cross-flow radiators are way better than vertical-flow radiators for this reason. And then GM starts building vertical-flow radiators after decades of cross-flows, for the GMT360/370 Trailblazer/Envoy series of vehicles.

was it because narrow front but tall bay (i6 atlas fits i guess)

 

[Supercharged111]

Thank you. There's so much misinformation about cooling systems floating around automotive forums. Nice to see truth.


Technically true, but the "draw" (I'd have said "inlet" or "suction" side) SHOULD be the already-cooled fluid coming directly from the radiator.

Water pumps can cavitate, though. I think it has more to do with impeller speed and inlet restriction rather than inlet temperature.

Similarly, when there's a problem with the lower radiator hose collapsing, most folks say to shove a "spring" inside to "support" the lower hose. I say to check the radiator for restriction. If the lower hose collapses, it's because you're pumping water out of the hose at the water pump end, faster than it can re-fill from the radiator side.


Propylene glycol (PG) anti freeze is popular with the Eco-sensitive; I've used it too. Doesn't poison dogs or squirrels who might drink a little out of the coolant drainpan left unattended too long. I figure it's better to appropriately contain 'n' dispose of the waste anti-freeze in a timely manner. But like I said, I've used the stuff and it worked OK. Been a long time...

The PG antifreeze doesn't have to have anything special in the cooling system; it is just a little "thicker" than ethelyne glycol; and doesn't have quite the freeze protection. You'd need a different freeze-protection tester than Ethylene glycol.

https://www.amazon.com/old-world-sep003-antifreeze-coolant-propylene/dp/b000ccm5ja

"High flow" is very welcome...but only when the heat load demands it. The whole point of a thermostat is to choke-off coolant flow to make the cooling system much less efficient, so the engine warms-up quickly and stays at a reasonably-steady temperature. This is why engines operated at idle or cruise should run within a few degrees of the thermostat rated temperature; if the engine is more than 20-ish degrees above the thermostat rating, it's lost control of engine temp. Of course, some of that depends on when the fan(s) are activated--GM often doesn't turn on an electric fan until 220 degrees or so. The second electric fan may not come on until 230. If the cooling system is running way hot at idle or cruise, it's got no reserve capacity for when you're dragging a trailer up the mountain, or other heavy-throttle use. THAT is when the thermostat should be WFO, and the engine coolant temp may climb some.

The "big deal" with having a restrictor in the thermostat housing--either an actual thermostat, or a restrictor disc--comes from the older, top-to-bottom flow radiators. UNLIKE a typical cross-flow radiator, the pressure cap is on the inlet side, ahead of any restriction presented by the coolant tubes in the radiator. Having radiator-cap pressure, PLUS water pump pressure (especially at high water pump speed) that isn't moderated by the restriction, will overpressurize the radiator cap, causing it to release pressure and therefore loss of coolant. Then the system is low on coolant, so the engine overheats.

A cross-flow radiator has the pressure cap on the outlet side, so it maintains cap pressure despite water pump suction, leading to higher overall pressure within the engine. Cross-flow radiators are way better than vertical-flow radiators for this reason. And then GM starts building vertical-flow radiators after decades of cross-flows, for the GMT360/370 Trailblazer/Envoy series of vehicles.

I'd argue that's the least of the evil they put into that platform.