For a bit of context, I recently picked up my first xj and have been nursing it back to health from its somewhat neglected state. Generally it’s pretty unused, but hasn’t been well attended in terms of fluids and other regular maintenance.

The other day headed up a mountain (not off-roading, just heading to a trail head) and got the dreaded check engine light and noticed the temp was sky high. When I popped the trunk I could see coolant spewing out from under the radiator cap. I let it cool and headed home, and drove it in town with no further issues.

Regardless, I did a coolant flush and replaced the radiator cap as the coolant looked pretty brown. All seemed to be fixed until yesterday when I headed up the mountain again and got the same results, except this time the temp looked normal and the check engine light didn’t come on. What could be causing this spray? A water pump issue? Blockage? The radiator itself? Any help would me much appreciated!