So I can run my jeep all day never over heat but as soon as I shut it off I begin to boil and over flow my system. The bad thing is it then air locks it
does not have a presurised cap. coolant mixture is a 50/50. would converting to a presurised system solve this issue?
1990 6I.

 

Yours shoudl have a closed "pressurized" system.
What do you mean by "does not have a pressurized cap"

 

just that the cap is a nonspring cap to creat presure. kinda wondering now if some one just found a cap and placed it on there not knowing the differnce. have not had the jeep that long. so being 20 years old im sure now that thats what happend, so problem solved.

 

YOu should have this bottle in the right corner. The cap should look about the same.
If that bottle has any cracks, it will cause it to overheat/boil. Pressure is what keeps the coolant from boiling

 

Or you simply have more water than coolant in there so the boiling point is not high enough ...

 

fluid ratio is fine the cap this is more like a lawn mower gas cap tho so i think ill pick me up a new one.