cooling issue....custom car

[craig3x]

This may be a very dumb question, but when you first start a car and the thermostat is closed so that the engine can warm up, what happens to all the coolant that the water pump is still trying to push? Seems like it has no where to go since it is not looping through until the thermostat opens.

[TitaniumTT]

Originally Posted by craig3x

thats something I haven't thought of. I will fill the system from the highest point and see what happens. I have 2 radiator caps. one in the front and one on top ot the waterpump fill neck. The one up front has leaked before. maybe I need a higher pressure cap up front?

The lower the pressure in the system the better... to a certain extent based on the coolant you're using. 13psi is what I'm using.

You want to bleed the system at the highest point last. Something you might want to add to the system is an expansion tank, I swear by them now. Installed properly they will automatically and constantly bleed the system unless there is an air bubble big enough to jam up the waterpump. If that happens you're screwed and the temp will just skyrocket. With air in the waterpump, the coolant will not move at all.

Originally Posted by craig3x

how do you perform a propper pressure test?

With a proper pressure tester. With the car cool, hook this little tool up to the rad cap, which ever one, and pressurize the system to 110% of the cap and watch for the leaks.

Originally Posted by craig3x

This may be a very dumb question, but when you first start a car and the thermostat is closed so that the engine can warm up, what happens to all the coolant that the water pump is still trying to push? Seems like it has no where to go since it is not looping through until the thermostat opens.

it flows through the heater core (if it's open) and weeps through the t-stat.

[craig3x]

Originally Posted by craig3x
This may be a very dumb question, but when you first start a car and the thermostat is closed so that the engine can warm up, what happens to all the coolant that the water pump is still trying to push? Seems like it has no where to go since it is not looping through until the thermostat opens.

"it flows through the heater core (if it's open) and weeps through the t-stat".

hmmm, but I don't have a heater core. And I guess my question is that if I installed one of those fancy 50gph electric pumps, what would happen when the thermostat is closed? sounds like major pressure build up???

[FerociousP]

Originally Posted by craig3x

Originally Posted by craig3x
This may be a very dumb question, but when you first start a car and the thermostat is closed so that the engine can warm up, what happens to all the coolant that the water pump is still trying to push? Seems like it has no where to go since it is not looping through until the thermostat opens.

"it flows through the heater core (if it's open) and weeps through the t-stat".

hmmm, but I don't have a heater core. And I guess my question is that if I installed one of those fancy 50gph electric pumps, what would happen when the thermostat is closed? sounds like major pressure build up???

Then you would need to route the outlet on the back of the iron (near the oil press sensor, and create a bypass after the thermostat (see the bottom of an FC radiator. The little hose is the heater return.