Car getting real hot....
Yellow rose, actually you can have too fast flow threw the radiator. A/C equiped cars had a water pump with fewer vanes on the impeller to slow the flow through the radiator for more temperature exchange to prevent overheating in traffic.
The rad cap has nothing to do with temperature as long as it is not letting coolant out.
I would be looking at the fan and fan speed. Is the fan an electric with the radiator? Those need a 40A relay and 8ga wires from the battery, through a 40A fuse, through the relay and to the fan. A temp switch rated at 190° in the bottom tank will control the relay. Remember it needs an equal ground for the fan.
If the fan is on the WP, does it have 5 plus blades and it should be centered front/back in the shroud.
You could also try the A/C WP.
No, you can’t move the coolant too fast through a radiator. That is wrong. Think about what yo are saying and what you want me to believe.
You are saying use less flow so the coolant stays on the radiator longer. So I’ll ask you. What happens when the coolant spends more time in the radiator???? The coolant in the block and heads spends an equally longer time picking up heat. So you gain nothing and lose the ability to keep the coolant temperature closer to the thermostat opening point.
It’s really that simple. If the coolant coming out of the engine is staying there long enough to leave at say...210ish, and the system is capable of a 20 degree temperature reduction then the best you can hope for is a 190 degree coolant temp. Doesn’t matter if you have 190 thermostat or a 160 degree thermostat.
If you speed up the coolant so it doesn’t stay in the engine as long and the coolant is now leaving the engine at say...195 then you can reasonable expect to keep the coolant right at the 190 degree thermostat opening.
So we can keep going. What if we can keep the coolant coming out of the block at 180 because it doesn’t stay in there so long? That would mean you could reasonably expect that with a 160 degree thermostat you would be right at thermostat opening. Maybe not on a 105 degree day, but certainly when ambient temperatures aren’t hotter than the hubs of hell.
With my cooling system, I run a 160 degree Stewart Components high flow thermostat and on 100 plus degree days it will run at 160. All day long. If I get stopped by a long train it might, maybe might climb to 170 or a skosh more. I’ve never seen it hit 180.
That’s one reason why you don’t slow the coolant down. Overdrive the pump as fast as you can find pulleys and to the limits of keeping the belts on and the fan blades on the fan.