[Bryced1]

hey all, my 97 zj has 35k miles and overheated this morning, it was 8 degrees outside. at first i thought it is probably the thermostat, but i noticed the fluid in the resivoir was boiling over, and my heater wasnt working, which doesnt point to a thermostat. any thoughts at all?

 

[MaineMan]

Blown head gasket??!

 

[GreenZJ]

35K, nice! As for overheating, check your waterpump, make sure you have enough coolant in it, also check to see if there is a clog somewhere in your system. feel if the upper and lower hoses are hot or not and report back

 

[Bryced1]

both hoses are hot.

i dont think its a head gasket, it runs strong, smooth idle and it hardly ever gets off the pavement, doesnt use coolant and theres no coolant in the oil or vise-versa.

is there any problem with the cooling system that would cause the heater to stop working?
even at normal temps it blows cold air.

 

[GreenZJ]

It sounds like there isnt enough coolant in the system. you could easily have a small leak in a hose. Like said, check your hoses, check the weep hole on the water pump, Most likely if its a hose, its the bypass hose which is a pita to get to

 

[Bryced1]

the coolant level is good, possibly a clogged heater core? does anyone know how to do the garden hose trick to unclog it in a zj?

 

[rockrknockr]

ok

1. you are not losing fluid, so NO LEAK

2. you are overheating, overflow reservoir BOILING

3. heater not blowing hot air

a. i don't think the heater is getting hot water, you already know that.

b. if the t-stat doesn't open then you WILL overheat. check the t-stat again

c. if the water pump stopd working then you will overheat. check the water pump again.

d. where does heater hose originate? i am not looking under the hood of my GC right now

and all this while the air temp is 8*...........go figure