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Stock JK TechBulletin board forum regarding issues with OE (original equipment) components of the Jeep JK Wrangler (Rubicon, Sahara, Unlimited and X) such as factory suspension parts, engine, transmission, body parts, interior fixtures and the on-board computer.
I've been having coolant leaks the past few months, it's taking about a gallon a month but couldn't figure out where it was coming from. (Clean radiator, reservoir is good, pump looks clean, lines looked good.) Finally found a pool of coolant against the intake manifold on the driver's side. I couldn't find any exact hits on my searches but seems like the lower intake manifold gaskets might need replacing but I haven't seen anyone post about it pooling up right there. Any ideas on what else it could be or what it might cost to fix?
Hairline crack, loose hose clamp or bad dry rotted gasket at the plastic hose thermostat housing located at the engine block. The puddle of coolant is where the coolant is collecting being blown back onto the manifold from this hairline crack. Replace the plastic thermostat housing, gasket and the thermostat.
Lower intake manifold gasket on that 3.8L is a common issue. Given the area of pooling, I suspect that is probably your culprit as you mention. I actually just dug up Rednroll's old links for another member/thread. This might be useful reading for you as well -
Hairline crack, loose hose clamp or bad dry rotted gasket at the plastic hose thermostat housing located at the engine block. The puddle of coolant is where the coolant is collecting being blown back onto the manifold from this hairline crack. Replace the plastic thermostat housing, gasket and the thermostat.
Sharp eye, yeah, you can see coolant running back from the Tstat housing. I would definitely address that first.
Well, I got the thermostat off, looks pretty new and there wasn't anything around the housing itself. What's really concerning me now is that the hose going to the housing was empty and the level inside the engine was about an inch and a half below the thermostat itself. From what I've seen both of those should have been full which leads me to believe the leak is below this??
I'll try a new sensor right there, hopefully that's it... Looks gunked up...
I chased a leak for a year and finally the hairline crack on the plastic thermostat housing exposed itself. Look very closely to this housing as I suspect this may be your problem.
12-27-2020, 03:34 PM
Coolant leak
