Hi there, my 2012 JKU Sahara has 158k on it with regular maintenance. Overheated on the highway a week and a half ago with radiator suddenly empty. Filled radiator and reservoir with coolant and ran perfectly fine (no leak observed), no sounds, sights, or issues and stayed at normal temp until last night. Again on the highway temp alarm goes off. Pull over and don't see any leak, radiator and reservoir still full. Towed it to a shop and then had massive coolant coming from back of engine coming down over trans and dripping on either side of oil pan (video attached, better video too big so working on getting a youtube link for it). They checked thermostat, water pump, and coolant issues and didn't see any issues. Next step is checking freeze plugs. Hoping it is not oil cooler issue as that's a pain to do but well see. Just looking for any insight you guys may have on how to diagnose. It is technically driveable, starts and runs fine minus the leak and overheating.

 

Video didn't have any picture for me. If it's coming down the back of the engine, and it's not the heater core lines at the firewall, then it seems it has to be the oil cooler which you know is under the intake manifold. I'd suspect a bad o-ring if that is the case....it would fill the valley between the heads and then pour out the back. the valley has bulkheads in it as you can see in this picture from one of my old threads -



That valley can hold a decent bit of liquid and then it's escape route is the back of the block. You could possibly get a decent horoscope up the back and into that valley from behind and get a look if things are pooling there. there is zero space to observe from the front. I really can't recall the access from the back at the moment so that might not really be possibly with the lower intake installed.