Radiator Resevoir cap issues

[wildcatfan94]

My daughter has a 2000 3.0L v6 ford ranger that keeps having an issue with the Radiator Resevoir cap that keeps blowing off and antifreeze/water blowing out the top.Anyone know what could be causing this. Yesterday I put on a new thermostat and radiator cap.

 

[Hopman]

Overfilled coolant or an air bubble in the system is my guess.

 

[wildcatfan94]

Its not overfilled, I check it when its cold and fill the radiator and then the resevoir to the full mark. If it has a air bubble how do you get it out? Will it work its way out, because this has been going on for over a week.

 

[strvger]

take it where they will do a coolant system flush and that should do it. should cost less than $40-50 depending on where you live. make sure they flush thru the heater lines as well.

 

[cocoasranger]

Its not overfilled, I check it when its cold and fill the radiator and then the resevoir to the full mark. If it has a air bubble how do you get it out? Will it work its way out, because this has been going on for over a week.

There are two full marks on the reservoir, full hot and full cold. Might want to check this, the lower one is the cold fill mark.

 

[wildcatfan94]

The low one is the one I filled to

 

[LearjetMinako]

You may have bigger issues. Air bubbles in the coolant would not cause this. The cap is designed to let expanding air out and let coolant flow back in the system when the engine is cooling off (shut off). You may have a gasket leak or a blown head.

Something to check. With the engine fully cold, take the coolant cap off and then start the engine. Look for a constant stream of bubbles coming up. If thats the case, then you got a big problem.

Also, make sure your coolant is 50/50 mix. Too much water and it will turn into steam and overpressurize the system. But thats pretty much in like a 10/90 mix.

 

[MrE_Powers]

coolant leak some where, Hopefully not at the head gasket. get a coolant pressure tester and see if you can find the leak, i had the same symptoms and eventually had to change just about every thing from the radiator which had seam leaks to the heater core because it was clogged

 

[lil_Blue_Ford]

You may have bigger issues. Air bubbles in the coolant would not cause this. The cap is designed to let expanding air out and let coolant flow back in the system when the engine is cooling off (shut off). You may have a gasket leak or a blown head.

Something to check. With the engine fully cold, take the coolant cap off and then start the engine. Look for a constant stream of bubbles coming up. If thats the case, then you got a big problem.

Also, make sure your coolant is 50/50 mix. Too much water and it will turn into steam and overpressurize the system. But thats pretty much in like a 10/90 mix.

Agreed. I've been there and done that...

My choptop for awhile was eating heads like candy until I swapped motors, you can check for what looks like milkshake or snot on the oil fill cap after running it, but you can still have a bad head/gasket and not have that sign. Bubbles in the overflow when it's running with a proper antifreeze mix usually means the head or gasket is shot, although I've heard of rare occasions where it would bubble because of a blockage (say the heater core plugged up or the thermostat sticking).