ok so i just changed my coolant and thermostat last week and now everytime i run the ac, coolont bubbles up and overflowing out of the expansion tank.

The truck is nowhere near overheating, in fact i replaced the thermostat that opens a few degrees cooler.

i did my own mix of coolant and distilled water 50/50, i purged the air from the system like i was told to by my haynes manual any ideas??

 

Did you try turning on the heater full blast, to get coolant flowing through the heater hose? Sounds like you're getting no flow somewhere. Does it do this with the AC off? Weird!

 

no it doesnt do it when the acs off only when i use it and ya i ran the heater on full blast to get it flowing when i first filled it up with coolant. Maybe i just didnt do it long enough?

 

update today drove about 30 minutes on the freeway with the ac off, and it still overflowed the truck is running at 185 degrees yes i put in a thermostat that opens cooler. it doesnt make sense im not even close to overheating