Rednroll

The radiators have been known to leak from the end caps either on drivers and/or passengers side. However, a pressure test should be able to expose that problem and seeing as though you've had multiple radiators replaced I would guess your leak is somewhere else.

The heater core is another potential leak area, where it tends to leak at the elbow joints. That would also be difficult to see the leak during pressure testing since it's mounted inside behind the center of the dash. To check this, you could purchase a 5/8in ID piece of heater hose and bypass the heater core, and if your coolant smell disappears then you know the HC needs to be replaced.

Another common hard to find leak area is the Lower Intake manifold gasket. However, that is a problem which seems more common on the pre 2012 3.8L JKs or I just haven't seen anyone post that they needed to replace the LIM on the 2012+ 3.6L.

The thermostat housing is a more common leak area on the 3.6L as well but should be found with pressure testing. Then there's also the possibility of the water pump.

Hopefully, that gives you some ideas of where to inspect. I'ld start with the heater core.

Nonblonde1983

Ok I have been having issues for awhile and have searched and searched any help is much appreciated....

2013 Jeep Wrangler Unlimited Sahara 3.6.. 194K miles...

Noticed Temp was trying to get hot and started smelling coolant.. Changed the water pump out it was leaking from the weep hole. Jeep never went above 3/4 on the temp gauge.

I am still having issues. I refill my coolant every 2-3 days.. It never leaks while sitting. The other day I crawled underneath after driving it and notice blow back coming from the back of the engine. I have looked and looked and cannot seem to find a leak. Any one have any ideas?

Thanks in advance!!

Rednroll

Take to a shop and have them pressure test the system to find the leak, or purchase a pressure tester to find it yourself. Those are the best ways to find a coolant leak.

hornetman

I had similar problem with coolant odor and after several months of changing temp sensor, thermostat, water pump and still having coolant loss found that the thermostat housing had a hairline crack, coolant would pool up around the temp sensor and after changing sensor and then pulling out to reseal still continued until the crack in the housing finally got bad enough that I pulled it and found the crack.

Nonblonde1983

If it was the heater core wouldn't I have coolant in my floor board? And thanks I do plan on getting a pressure test kit.

Rednroll

If it's just a mist spraying out, it may be difficult to detect on the floor board. Some have mentioned when they had a HC leak they observed a fogging on their windshield from the coolant.

tjkamp

My heater core was leaking so bad I couldn't run the heater for the smell of antifreeze, I dont have any carpet in the Jeep, just bare body colored floor pans, never had any sign of coolant on the floor, not oven a sheen or anything. Changed the heater core and that smell went away. Still have a smell from under the hood, I am starting to think it is from the lower intake/oil filter housing area, noticed some staining in that area the other day, but it is too far in there to get a sample to smell to see what it is.

Nonblonde1983

Update: I crawled underneath it yesterday and its really hard to see anything, but it was all over my transmission pan and leaking from up above somewhere. I will crawl back under today or tomorrow after work and see if I can investigate it any more. Whatever it is its getting worse. and I never smell antifreeze in my Jeep just outside when I stop.

cedarraider

Mine only lost a drop or two a month but would smell coolant every time it was ran. Most likely it is leaking along side the plastic tanks behind the fan. It only takes a few minutes to pull the fan out and check.

resharp001

So, if I'm understanding correctly, it sounds like it is leaking within the engine bay (definitely not interior), and the leak is towards the rear of the bay if you're saying you're seeing signs of it coming down the transmission pan?? I can't recall on mine or not, but can you get a good look at the lines running through the firewall towards the heater core?

Rednroll mentioned getting a pressure test. You can also pick up a pressure test kit as part of Autozone (or other auto store) tool lending programs. That way you could pressurize the system yourself and then crawl under it to see if you notice anything. Usually our leaks are pinhole leaks at the radiator, but it sounds like you have something a bit more extreme going on. I'd think pressurizing the system would help, and also give you an indication how bad a leak you might be looking for depending on how quickly the pressure drops.