I have a 94 yj 4 cyl I am having trouble finding the cause of this but if I run my Jeep a little too long in the summer it over heats like it will boil the coolant like my thermostat is stuck closed then in the winter I’ll go start it in the morning for like 20-30 min and when I get out there it’s not warm at all maybe just over 100 on the temp gauge but as soon as I start driving it slowly heats up to 210 witch is normal but if I stop somewhere and let it idle for 5 min it drops down to 120ish kinda like my thermostat is stuck open and my heater used to make me sweat and now it’s just kinda warm so here is what I have done
and still does it
Thermostat 190
Drained radiator
Flushed it both ways with a hose
Flushed heater core
Flushed with blue devil ratiator flush
Refilled with concentrate and water 50/50
Blew my heater core out with compressed air
And tied my vent door shut
It doesn’t burn coolant or leak it at all but I’m not understanding why is would go from not heating up in the winter to boiling the coolant In the summer
Any ideas?
and still does it
Thermostat 190
Drained radiator
Flushed it both ways with a hose
Flushed heater core
Flushed with blue devil ratiator flush
Refilled with concentrate and water 50/50
Blew my heater core out with compressed air
And tied my vent door shut
It doesn’t burn coolant or leak it at all but I’m not understanding why is would go from not heating up in the winter to boiling the coolant In the summer
Any ideas?