Coolant question

[rtstrack]

I'm trying to figure out if my cooling system is working properly and could use some help. I have a coolant catch can mounted below my radiator with a small hose connecting from the top of the radiator to the bottom of the catch can. When my car is completely cold the catch can is filled with coolant. After running for awhile and checking the catch can, it will be down about half way (20 ounces or so). Then when the car cools again the catch can is back up to the full mark (no coolant loss). Is the system working properly? Is the engine full of air and then being replaced with coolant as the engine starts to warm up? Thanks

Ryan

[undy]

Originally Posted by rtstrack

I'm trying to figure out if my cooling system is working properly and could use some help. I have a coolant catch can mounted below my radiator with a small hose connecting from the top of the radiator to the bottom of the catch can. When my car is completely cold the catch can is filled with coolant. After running for awhile and checking the catch can, it will be down about half way (20 ounces or so). Then when the car cools again the catch can is back up to the full mark (no coolant loss). Is the system working properly? Is the engine full of air and then being replaced with coolant as the engine starts to warm up? Thanks

Ryan

Actually the inverse should happen. That assumes you have a closed/sealed system. Are you sure you don't have it backwards?

Water/antifreeze expands with heat in the engine and starts to fill the catch can. As the car cools and the water contracts in the engine it pulls back the water from the catch can by vacuum. So... cold engine, catch can almost empty. Hot car, catch can fills up. You car can't defy physics..

[rtstrack]

I thought things were screwy. Apparently my car is special because it is indeed defying laws of physics. I always check catch can before i go out for a ride and it is always at the same spot (3/4 full at the "full" line) and then when i get home i double check it after the temp gauge gets to read real high and the catch can is ALWAYS down half way. I let the car cool off and check my overflow tank and its back to the "full" line exactly. What in the world could cause this? One thought is my coolant hose running from my thermostat housing to the upper radiator outlet is too long and is actualy arching up because of it. The arch is physically at a higher location then the radiator cap. My radiator is slanted back at an angle, is it possible the top of the radiator is sitting lower then my intake and therefore leaving the system sitting empty?

[rtstrack]

Should the overflow tank be mounted above the radiator instead?

[PANAVIA]

overflow tank tops are usually inline, level with the top of the radiator or slightly higher.

the only think i can think of is that you are experiencing some sort of capilary action when the engine is running , sucking up the coolant into this system then gravity is pushing it back out/down to the bottle when the engine is off.

[rtstrack]

i was planning on adding an expansion/surge tank between the t-stat housing and the upper radiator outlet so that I could be sure i have a fill point that is sitting above the rest of the system. I think that seems like my next step