high flow themostat question

[blazer2007]

anyone out there using the high flow thermostats,and do you think it helps in these hot summers.

[swb85]

Depends what you're running for a cooling system. If you have a high flow water pump, you need a high flow thermostat. Otherwise a standard thermostat should be fine if the rest of the system is sufficient. I run a high flow 180* with a high flow water pump and it works great. Keeps temps right at 180* sitting in 100* ambient temps with the a/c on.

I tried to run a standard 180 stat with the high flow pump at first, but temps would climb above 195* on the highway because the pump was moving so much water it was forcing the thermostat closed. Switched to the high flow thermostat and she's cool as a cucumber now.

[Rooster's82]

My truck calls for a 195* t-stat...isn't that standard for all 350's of this era? What is the benefit of a 180* set-up?

[swb85]

For most street driven small blocks, 195* is just fine. On my 383 I run quite a bit of compression for iron heads & 91 octane gas, I run a 180* to help ward off detonation.

[LONGHAIR]

temps would climb above 195* on the highway because the pump was moving so much water it was forcing the thermostat closed.

The thermostat opens away from the flow of coolant. It is not possible for coolant to force it closed.

A high flow thermostat is, in itself, not going to aid in cooling. The thermostat is nothing more than a "switch" that opens and closes the radiator from the rest of the system. It is not as simple as on/off though. There is a bit of "regulating" going on too, depending upon water temp. So, if your stock-flow thermostat is not fully open all of the time (and un-able to keep-up with cooling) then increasing flow at the 'stat wouldn't do anything for you.

The point of the whole thing is the heat exchange ability of the radiator itself. Of course hotter air does not remove as much heat, so hotter weather does have some effect on the system as a whole. Once the coolant is at maximum flow ('stat fully open) in a clean, smoothly flowing radiator.....more fluid flow speed is not the answer. The radiator is not removing the heat. There is not enough radiator surface area, or the cooling air is too hot to make enough difference. Since you really can't change the incoming air....all you can really do is improve the radiator's efficiency.

All assuming that you do actually have a problem.....

[swb85]

Originally Posted by LONGHAIR

The thermostat opens away from the flow of coolant. It is not possible for coolant to force it closed.

Unless you've got the thermostat installed upside down, a standard thermostat opens down into the intake.....against the flow of coolant.



From Milodon's website:

The high flow "Balanced Sleeve" thermostat is highly recommended for use with High Volume water pumps. With other thermostat designs (like the pic above), the increased flow generated by High Volume water pumps can actually attempt to hold the thermostat closed. The "Balanced Sleeve" design equals the pressure exerted on the thermostat allowing its operation to be solely regulated by coolant temperature.

This is exactly what was happening in my truck. With the standard stat, my coolant temp went up at highway speeds but cooled back down at lower speeds. Now with the high flow stat, my temps don't climb on the highway anymore.

Originally Posted by LONGHAIR

The point of the whole thing is the heat exchange ability of the radiator itself. Of course hotter air does not remove as much heat, so hotter weather does have some effect on the system as a whole. Once the coolant is at maximum flow ('stat fully open) in a clean, smoothly flowing radiator.....more fluid flow speed is not the answer. The radiator is not removing the heat. There is not enough radiator surface area, or the cooling air is too hot to make enough difference. Since you really can't change the incoming air....all you can really do is improve the radiator's efficiency.

All assuming that you do actually have a problem.....

Actually (up to a certain point) more fluid flow IS better. Read this, scroll about halfway down. Thermodynamics can get real confusing.
http://www.arrowheadradiator.com/14_...utomobiles.htm

[blazer2007]

would a 160 thermostat help in keeping the motor cooler

[LONGHAIR]

would a 160 thermostat help in keeping the motor cooler

Not really, it will just let the coolant flow into the radiator earlier. It may have some effect in the winter, when the incoming air is much cooler. Unfortunately, your heat/defrost suffers for it though.
The "equalized temperature" is basically controlled by the radiator's efficiency and the incoming air temperature. When the air is warm, there is not as much temperature drop across the radiator. This is especially bad in a "borderline situation". At that point, the thermostat is fully open and everything is flowing freely/fully. If you introduce more heat, from towing, long hills, etc. and the system is at capacity....your temp goes up. (That same hill or trailer might not cause overheating in cooler weather)
If that is indeed the case, increasing the radiator's efficiency will help you the most.