Does This Debunk the "Coolant Can Flow Through the Radiator Too Fast" Idea???

If you radiator won’t cool and it’s aluminum, it’s not not cooling because of what it’s made from.

I agree, in our application if a car isn’t cooling it’s not because the radiator is aluminum
So my over simplifications aren’t really.

They are facts.

Almost no one disputes that two big cores will out cool four smaller cores. You aren’t building a radiator out of brass or copper or some mix of it that will tolerate two big cores.

Again, that’s a fact not a simplification.

Actually it is again a wild oversimplification. Because if we’re talking about a 4 core brass/copper radiator and a large tube 2 core aluminum radiator it is NOT a slam dunk that the aluminum radiator will cool better. It simply is NOT a fact. You’d have to test those individual radiators, and the result would depend on the individual construction. It could easily go either way.

Saying otherwise is simply a wild *** guess.
Buying undersized junk **** and not grasping what it means when you have a 180 degree thermostat and the engine on hot days is running at 200 they should know their cooling system is NOT doing its job.

It’s failing at its job.

Nope. Another simplistic over generalization.

Yes, the thermostat only sets the minimum temperature.

In general your cooling system should be able to maintain a temperature within the operating range of the engine. The thermostat has no effect on that, it’s out of the loop the moment it fully opens. So if your car maintains 180, or 190, or 200 once the thermostat is open that has nothing to do with the thermostat and everything to do with your engine, it’s tune, and your cooling systems capabilities. If you run a 160° thermostat and your car will maintain 190° regardless of the situation it doesn’t indicate an issue with the cooling system at all.

Yes. If it won’t do that the cooling system is not keeping up.

I’d love to be able to not run a thermostat at all. I don’t want or need that restriction.

And I tried that. It was a hundred degrees out and about 90 in the shop. I barely got 140 degrees out of it. That’s too cold to run the defrost in the winter.

So I use a 160 thermostat to set my minimum temperature. If my cooling system wasn’t capable the engine would run hotter than what the thermostat is rated to open.

As it is, on 100 degree and hotter days if I have to sit at a long light it will creep up to 170.

That’s because I’m only turning the water pump 6% over crank speed.

I’d bet everything I have, everything you have and a bunch of stuff neither of us have that if I can drive the water pump 20% faster than the crank that I could sit at a stop light in downtown hell all day and it would stay at 160.

This is silly. Why are you worried about the “restriction” from the thermostat if your cooling system works well?

As for the amount of over or under drive it totally depends on the pump itself and the rest of the system. AC Mopars were overdriven at 30-40%.

As far and maintaining within 10°, sure, that indicates a robust cooling system, but that’s not a standard that indicates anything less is junk. If your car maintains 180° all day with a 160° thermostat you’ve got no issues at all.


Run Forest Run. If you are relying on the speed of your water pump to cool your engine you don't understand how your cooling system works. The rad is the heat exchanger and it must be the correct size and design to remove the the heat your engine produces.

Nope, not true. Pump speed is very important, and has to be matched. Again, Ma Mopar changed the speed of the pump by over 30% depending on the engine and options. It’s not the only thing, but it’s a thing. There are several threads here where members solved their overheating issues just by changing their pump drive ratio. Mostly after realizing they were unintentionally under driving their water pump.