kenheehn3

I haven't worked on my jeep for a few months due to snowmobiling instead, and today I decided to install my new radiator to fix the leaky one previously installed, and I got it all in and the truck was running great then all of a sudden it started to almost overheat. Does anyone know what would cause this? Like I said it has a new radiator, coolant flushed, new radiator hoses and a new coolant overflow bottle. Any help would be greatly appreciated!
Thanks
kenny

redrunner

Are you running an open (after market installed) or closed system that the 90 came with? The bottle on the fire wall with a hose in the side and another in the bottom with steel Ts? If it is a closed system it more than likely has air trapped in it....just like any baby it needs to be burped. Check for other threads for how to correctly burp the closed system. I have replaced the closed system on both my 89s for an open system. Great move to change it over!

DKCherokee

Did you replace the thermostat?

And also, did you make sure to purge the system of air when adding coolant?

When I replaced my rad on my 99 Cherokee, I replaced the hoses, thermostat too, and rad of course. I filled up my rad, capped it, then started the engine as coolant was still in the engine. I then opened the cap and kept filling till it was almost overflowing. For the next week, I would check the overflow tank, and top that up until it finally didnt drop in coolant level.

IT'S AN XJ THING

ya....pull the cap off when its cold then start it and run it for 30 min. (watching the temp gauge) and don't add coolant, just let the air bubbles circulate and escape.

kenheehn3

Last night right after I installed it, I filled the tank and left the cap off and let the truck run for probably 20 minutes and a lot of air did come out, but then all of a sudden it decided it wanted to be a ***** and overheat

fantic238

are the fans ok? electrical and mechanical?

kenheehn3

Clutch fan works perfect and the electrical one I wired to a toggle switch and is turned on at all times.

kenheehn3

I think I just have a gigantic air bubble somewhere and I need to get it out, I have been reading for a while how to do so. Tonight that is my project, I will keep posted.