So my radiator fluid is backing out of the overflow, first assumption, Thermostat.

Im pretty sure thats the problem, but like an idiot... i didnt look at the old one before i took it out to see which way it goes in.

Does anyone know which way is the correct way it should be in?

its an 88 by the way.

 

I'm pretty sure the spring goes towards the engine

 

well i know that, lol. but im pretty sure you have to put it in turned a certain way.

Never changed it on the cherokee, but i know on other vehicles if its put in upside down it wont work properly

 

If it matters there will be a tab in the housing and a matching notch on the Stat.

 

As long as the spring is towards the engine you'll be ok. Replace the radiator cap too, it goes over looked much too often.

 

so i put it in, cranked her up, when she got warm it is still backing out of the cap. it starts to back out around 130 degrees maybe a little less.

Other than the thermostat nothing else should be causing it to back out should it?

Could the cap cause this? i made sure it was as tight as it would go.

 

Can be the cap is bad it's been known for this to happen

 

ok so the cap isnt bad either. could the heater core be blocked up? can i bypass it?

Also, can i run without the thermostat?

 

Another thing, i let it run for a while with it overflowing, and it didnt get above 150 or so temp wise. and yesterday when i was driving, it didnt get above 210. so its not overheating, its just overflowing for some reason...

 

bump.

Still no ideas on why its blowing out the coolant.

any help is appreciated

 

If those temps are accurate, sounds like the cap/bottle are not holding any, or very little pressure. Temps need to be verified.

 

thanks djb, when i get a chance ill go to a jy n see if i can round up another bottle.

work will delay this as well as a trip to florida which i was hoping to be driving the xj.

 

The '98 FSM doesn't say "u must use a specific temp t-stat", but it does say "not using a t-stat is not recommended".

 

88 xj is a closed system air must all air must be out of system