wssix99

iTrader: (5)

Think of it more like an expansion tank. As the coolant heats up, it expands and builds pressure in the system. Excess pressure/coolant flows to the tank. When the car cools down, a vaccum is created in the system as the coolant shrinks in volume, sucking coolant back in to the radiator from the tank.


Sloshing and blow-outs are classic blown head gasket = not good.

Spartan7

iTrader: (7)

Yes, it should. Read the GM manual.

"A coolant recovery reservoir is connected to the radiator to recover engine coolant displaced by expansion. As the engine cools, the engine coolant is drawn back into the radiator by vacuum."

If yours is always dry, you're low on coolant. The reservoir is designed to keep air out of the radiator.

LS6427

iTrader: (2)

Not with mine, not for 14 years. My coolant is always topped off. I check it like once a week. Never is it it low. I've had the over-flow line off for a long time too....never was I low. Fact is, if the pressure never rises above ~18psi, nothing leaves the radiator. When I pull into parking after driving it my temps are always around 185-190, so I never get hot and never get over-pressure.

I'd like to see that process actually take place. I'd like to see how coolant can flow back into the radiator with the suction from cooling pulls the radiator cap seal on harder and harder.........the suction can't over-come itself. Either the cap will be too tight (from suction) to let coolant get in or the seal would have to get sucked into the radiator.

I just don't see it happening. My coolant is always topped off where when I check it the cap comes off wet. I can certainly see coolant leaving the radiator from an over-pressure, but going back in......maybe it happens, but that defies physics in a way. More vacuum pull, better the seal.

.

Spartan7

iTrader: (7)

Radiator caps have a pressure relief and vacuum relief valve. It uses a heavy spring for the pressure relief, allowing pressure over 18 psi to push its way back into the overflow tank. When there is a vacuum drawn by the cooling system, the vacuum relief valve allows coolant to be drawn from the reservoir.

This is a very well known design for radiator caps, it's been around for years. I really don't care what you say works for you. If it does, that's great. But that's not how the system was designed to work.