Sounds to me like your thermostat isn't sensing because the cores you have it next to are cooling down when you get wind. Or, the thermostat isn't tight against a core.
Some cores are plugged or half-plugged on the inside. They cool down quickly. Usually it's the ones used the most (right next to your inlet pipe). Since water takes the path of least resistance, flow goes to another core farther away. You can prove this with one of those infrared guns but you have to run real fast in front of the car while it's going down the road. Just sitting there, all the cores conduct heat because the hot air is stagnant. I suppose you could blow a hefty fan in front to simulate 35-mph air flow while using the gun in the driveway.
I'm surprised factory boy didn't recognize this right away especially with a classic car. I had my rad out and filled it with phosphoric acid to break down the lime deposits. I had the rad flat with liquid covering the cores. Then I ran my propane torch over each rib quickly at first. The cores that are free will boil the liquid inside and you can hear bubbles through the cap and hose openings. The ones that are plugged don't boil. It's tricky. At the ends, the cores are normally somewhat open. Running heat along the core, it will boil until the obstruction, then it will stop. Because acid works much better with heat, I went back and forth dozens of times until the dang thing cleared itself, right and proper-like.
Nothing beats a recored copper radiator, but this helped quite a bit. BTW, Prestone has a anti-rust chemical. Yep! Phosphoric acid in a mild form. Once it gets used up, no more anti-corrosion/anti rust properties.
Many of the solid state controllers are current direction sensitive. They will destroy if current is reversed. That's why I like using bullet proof relay contacts. Let the solid state take care of small signal currents so relays can do the real work.
The correct placement for the thermostat is at the radiator. At the engine's thermostat, it's always hot by design.
There's another problem if the radiator isn't full of coolant. Water pumps pull from the bottom of the radiator. Even if the coolant level is half way down, it still pumps. I see nothing wrong with putting the thermostat closer to the bottom of the radiator where you KNOW the coolant is. If airflow works, the coolant will stay cool (and not call for the fan). If not, it's putting hot water back in your engine and the stick should sense that. - Dave
Some cores are plugged or half-plugged on the inside. They cool down quickly. Usually it's the ones used the most (right next to your inlet pipe). Since water takes the path of least resistance, flow goes to another core farther away. You can prove this with one of those infrared guns but you have to run real fast in front of the car while it's going down the road. Just sitting there, all the cores conduct heat because the hot air is stagnant. I suppose you could blow a hefty fan in front to simulate 35-mph air flow while using the gun in the driveway.
I'm surprised factory boy didn't recognize this right away especially with a classic car. I had my rad out and filled it with phosphoric acid to break down the lime deposits. I had the rad flat with liquid covering the cores. Then I ran my propane torch over each rib quickly at first. The cores that are free will boil the liquid inside and you can hear bubbles through the cap and hose openings. The ones that are plugged don't boil. It's tricky. At the ends, the cores are normally somewhat open. Running heat along the core, it will boil until the obstruction, then it will stop. Because acid works much better with heat, I went back and forth dozens of times until the dang thing cleared itself, right and proper-like.
Nothing beats a recored copper radiator, but this helped quite a bit. BTW, Prestone has a anti-rust chemical. Yep! Phosphoric acid in a mild form. Once it gets used up, no more anti-corrosion/anti rust properties.
Many of the solid state controllers are current direction sensitive. They will destroy if current is reversed. That's why I like using bullet proof relay contacts. Let the solid state take care of small signal currents so relays can do the real work.
The correct placement for the thermostat is at the radiator. At the engine's thermostat, it's always hot by design.
There's another problem if the radiator isn't full of coolant. Water pumps pull from the bottom of the radiator. Even if the coolant level is half way down, it still pumps. I see nothing wrong with putting the thermostat closer to the bottom of the radiator where you KNOW the coolant is. If airflow works, the coolant will stay cool (and not call for the fan). If not, it's putting hot water back in your engine and the stick should sense that. - Dave
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