bleed coolant lines

[pp270]

how do you bleed the coolant lines to remove air from the lines.

I have a 2003 Montana.

I notice that the heat only heats up at higher rpms. 1500+. At idle there is no heat. The temp gauge also cools down at the same time as the heat comes on at higher rpm. The van was sitting for a while and the coolant reservoir went empty which I this is where air was introduced. If I feel the lower radiator hose under the water pump I can feel periodic bubbling. I am thinking the pump is cavitating from air and only overcomes the cavitation at higher rpms.

[rkvons]

Well I'm not sure about your year, but my '98 3400 has a little bleeder screw on the upper radiator hose (the one that goes from the engine to the driver's side of the radiator). You have to start the vehicle and open the bleeder screw and wait until it goes from bubbling to solid liquid as the negine warms up, then tighten it back down. You have to be careful not to loosen it too much, or it will come out and fall somewhere.

[LMP]

Originally Posted by pp270

....At idle there is no heat. The temp gauge also cools down at the same time ......I feel the lower radiator hose under the water pump I can feel periodic bubbling. I am thinking the pump is cavitating from air and only overcomes the cavitation at higher rpms.

If you have the possibility, make a CO2 test from the radiator cap. What you describe is typical of exhaust injestion into the cooling system....a head gasket failure problem common with this engine....with a myriad of threads about this issue.

[TooHipCat]

Is this vehicle equipped with a radiator fill cap? On my older vehicles I would start the vehicle up with the cap off and refill as necessary. When the coolant level would get close to the top of the engine, I would place my cap back on. I would use this method when I was starting a cold engine of course.

The only way to fill my Prowler is through the coolant reservoir unit...which is pressurized. So...when the engine is cold and off...I carefully (numerous times) squeeze the upper radiator hose to burp the system. Yes...I have a bleeder screw but it's rather difficult to access so I don't bother with it.

This proceedure works fine for me.

Good luck!