Coolant blowing out fill tank cap.

[Strokin_it96]

I have a 96 and after about 15-20 seconds of idling it seems to start building up a pile of pressure coolant starts foaming up outta the cap. My first thought was the rad was plugged somewhere but I wasn't sure if a bad thermostat would make it do that?

[phoenixrhino2]

I would first check that your T-Stat is functioning. Sounds like it may be stuck closed if you are getting pressure/heat buildup that quickly.

[Strokin_it96]

Well I changed the t-stat today, no change, still doing the same thing. I cracked the ECT sensor to let some air out and i got air, but then coolant so I tightened it back up and filled the tank and still the same thing. I then let it idle with the sensor out, and the cap on and I didn't get anything, until I cracked the cap and it all drained out and started pouring out the sensor hole. I'm at a stand still

[ryandamo]

im thinking injector cups?

[ajpu1983]

Sounds like cups to me.

[Strokin_it96]

yeah, i could almost bet 100% that's what it is because i just put stage 1's in the truck. thanks guys.

[Rockin J]

I'm new to this forum but I'm looking for some answers. I can drive my truck daily with no problems and my coolant doesnt drop. I hook up to my big toy hauler and she warms up to about 3/4 on the gauge and blows water out the tank. When normal driving it runs at about half on the gauge. Please help

[AD5GB]

Rockin J, make sure the fan clutch is working. You can definitely hear them when they engage. If that's not it then it might mean the radiator core is partially plugged. That would mean a trip to the radiator shop. I don't think it's a thermostat since it behaves well unloaded but it's a remote possibility as well. Good Luck

[Rockin J]

Thank you for the ideas, I just wantedto add that i have changed the thermostat and it still does it. Today when i got home from work and the truck was at op temp i left it running and got out and checked the top radiator hose and it was empty of any water and the Fill tank was only warm when i think it should def be hot to the touch. I called a ford dealer todayand of course they jumped right on that I had a blown head gasket. I would think that it would blow air through the tank all the time if that was the case. When i pull my trailer i do not hear the fan clutch engage when it heats up. Please send me any more help with this!!!

[AD5GB]

Originally Posted by Rockin J

Thank you for the ideas, I just wantedto add that i have changed the thermostat and it still does it. Today when i got home from work and the truck was at op temp i left it running and got out and checked the top radiator hose and it was empty of any water and the Fill tank was only warm when i think it should def be hot to the touch. I called a ford dealer todayand of course they jumped right on that I had a blown head gasket. I would think that it would blow air through the tank all the time if that was the case. When i pull my trailer i do not hear the fan clutch engage when it heats up. Please send me any more help with this!!!

What I used to do at the Ford garage to test them was first inspect them for excessive leakage. With the vehicle cold the fan shouldn't spin too freely. If it totally freewheels, it's junk. Then I'd block off the radiator and mount a thermometer and run the vehicle 'till it got to 190*. A good clutch should have engaged by then and on our trucks you can definitely hear them come on. These things aren't cheap for the PowerSmokes. I changed mine last spring. Like $160 or so. Can you hear your fan when you first start the truck?