The other day I was using my AC for the first time this summer,usually I have my windows down but the heat index was 114 that day so I needed AC. So I drove probably around 25 miles like that and I stopped to go get some ice cream. When I came out and started my jeep it was shaking, so I backed up and pulled into another parking lot which was empty and the engine light came on. When I opened the hood the engine coolent was bubbling over. So I parked it and left the hood open for about 10 minutes. When I came out I turned my ac off and my car ran fiine with no temp issues. Any idea as to why this may have happened?

 

my first thought is what condition is your coolant system in? Is the coolant good, are there any blocks in the lines, is the thermostat good. You said the CEL came on- get it on a code reader and find out what it says and go from there.. Its all guesses and headaches till then...

 

Which list is shorter.......what u have done (maintenance wise), what u have not done. The shorter the list, the easier it is to guess/help.

 

sure feels like the thermostat. i had a similar experience. It got hot but over about a 5-10 mile stretch. it's an easy swap, want to say less than $20. probably not a bad idea to go ahead and do a flush, too. Start simple.

 

I had my thermostat replaced about a year ago. So it might be that but I don't think so, cuz it only overheats with my ac on.

 

For others having problems with a coling system.

http://www.familycar.com/Classroom/CoolingSystem.htm


KEEP IN MIND- every 1 pound of pressure that the system is put under it raises the boil-point of the coolant

For example- the Glycol-water mix will now BOIL -because of the glycol at about 225 degrees NOT 212 anymore.
Adding pressure- for every 1 pound added it will raise the boiling point 3 degrees
Glycol-water mix under 10 pounds of pressure

225 + 30 ( 3 x 10 )= 255 DEGREE BOILING POINT

 

The check engine light or the "I may need a new cylinder head" light.

 

I'll bet you it shook because of vapor lock and next time dont shut it down right off when the a/c was just running, try letting it run a bit with the a/c off.(114) that day.But yes you should make sure everything is up to par with the cooling system.

 

 

Does the secondary cooling fan start when you turn the AC on?

 

Idk I may have to check that