01xj

Drove to the in-laws last night all the way in 4x4 and notice it was running a little hot didn't pay much attn I know that is the nature of the beast...So when I went to leave last night i went out to warm her up and i sat in the jeep while doing this 110-150-180-211 no heat I notice there was a little antifreeze on the ground where I was parked kept warming it up 220 nothing then jumped from 220 to 240 in a split second rad cap was boiling over and resovoir was filled still no heat big hose from rad to thermostat was hard and hot. I got a ride to the gas station and got some fluid and filled it up low about 2 quarts meanwhile the resvoir drained back into the motor\rad.I drove the jeep around for about 15-20 mins never over heated while driving still no heat? although the weather in mich last night was -18...What my thought are is that I have a stuck thermostat or i have too much water in there and its froze in my heater core.Now I did have heat on the way over there house. any thoughts>>

COSXJFAN

Heater control valve perhaps. IDK much about the newer XJs, but the older ones have a valve that is operated by vacuum, and opens the heater core up so coolant can flow through it. It sounds like you may have some other issues with your cooling system though.

havensov

Have you back flushed it recently? You might have a clog somewhere.

Just my thoughts?

RenoXJ

my thought is a stuck thermostat. can you tap the housing gently ... or just replace the 7.00 thermostat...

BuckB91XJ

Sounds like you may have a stuck shut T-stat and either the fluid froze up on you or you have a clog. Flush your whole system out really well and swap the T-stat. That should fix it. If not, it's definitely a good satrting point.