Air in cooling system, how???
 

Does anyone know a way for air to get pumped into the cooling system other than the head or gasket? For hours of running when full the air bubbles were coming up through the radiator and it would blow the water out of the reserve tank. Had to put water in it like every 50 miles to keep it cooling. I start to tear it down for the head gasket, pull the thermostat housing, pull the belt, fill it up, start it up, no bubbles. Race it up no bubbles. I'm stumped. It had no coolant leaks, just blows the water out. Could it be that it only leaks when hot? Any ideas, I have to get this thing running by tomorrow.

At the risk of sounding stupid, could it just be a bad radiator cap, just not holding pressure??????

sounds like a head gasket to me.

I 2nd a bad cap. Cheap place to start anyway.

Put a new cap on it when it all started. Did not change a thing.

take the truck to ur freindly neighborhood emission station and hold the probe over the rad fill neck and see if you are getting exhaust out. if so bad head gasket

In Alabama? You kidding, we don't have those things here, or inspections either. [laugh]

UMMMM ok my bad. Ok is the truck getting hot and over heating or is just the water being forced out of the rad cap. pull the injectors and look for white residue...

It does not overheat until it runs out of water which is forced out the overflow tank. Every fifty miles or so I can stop, let the pressure off, fill it up and it runs fine till it runs low again. My thought was the head gasket, already bought the gaskets, but there is no bubbles out the engine with the belt off and running.

Can you put in some dye to show which side the leak is on (if any)

dont know how else u could test it unless u did a compression test or cylinder leak down test. dont know what the correlation between the belt being off and on is but something is introducing pressure into the system. Dont know how the WP would do that it only circulates the water unless when it spins it draws air in from a weep whole somehow and is pressurizing the system but that would be a first for me..

Water pump cavitating???? :confused:

Dixie, do you have access to a radiator tester that has the pressure gauge on it, if so, put it on and see what kind of pressure you got. Could it be air trapped in the system and making the water turn to steam, which would blow the cap??? or could your radiator be plugging up un you??

Emission testing down here[laugh] [laugh] [laugh] We don't need to test, if it smokes, we got emissions[laugh]

How I have always checked for a gasket leak is the disconnect the pump, pull the thermostat and fill the engine up. Running there is no circulation so the gasses should come out of the thermostat housing. I see nothing. Well no choice but to pull it down I guess. Must be a high pressure leak under pull.

im sure u dont want to here this but a cracked head sometime does that after it warm but i have seen head gasket do it too