Unexplained Coolant Loss

[nagoya10]

The dealer probably never pressure tested the cap, just the cooling system. That may be why they never found the leaking cap. There are tester adapters for the cap.

After around 5 years, the Jeep radiators (any model not just Wranglers) can start slowly leaking where the aluminum section meets the plastic sides, usually drivers side and usually on the engine side but can be at any joint. Only way to find it is to use a good LED flashlight and look down in there for the dried pinkish residue. If you see any of that it’s new radiator time.

I did learn from this thread that Wrangler overflow tanks can leak also.

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[reldausa]

My Jeep had been losing coolant as well. First time took it to the dealer for them to do the pressure test and find no issues or leaks. They topped it off and asked me to keep an eye out and let them know if it drops again.

After a weekend off roading trip the level went down a little less than an inch so I took it back in. This time I asked them to do a more deep dive which they did. They tested the fluids and found hydrocarbons in the coolant, so they suspect a small head gasket leak.

They are now in the process of removing and measuring the heads, to see if they need to be completely replaced or just the head gaskets. They are also measuring the engine block and will also check the entire system from the heads down to make sure there is no metal in it. Apparently this is a common issue with these engines. Always ask your dealers to check the heads for any coolant leaks, or at least do a fluid test to see if there's any contamination.

I'm supposed to get my jeep back this week - i'll report back.

 

[Byrds8]

Well I am hoping the cap fixes the issue. If so I’ll be tickled. If not I’ll mention this to them. Granted it all points to the cap due to residue etc.

 

[roaniecowpony]

My guess is that it's this thing. This damn thing is the bane of the Pentastar in all forms.
My 3.6 was loosing coolant and this was the cause. I bet an oil analysis would show where the missing coolant is.

 

[Maverick909]

My guess is that it's this thing. This damn thing is the bane of the Pentastar in all forms.
My 3.6 was loosing coolant and this was the cause. I bet an oil analysis would show where the missing coolant is.

Glad you found the problem! Did you go with a stock replacement cooler?

 

[roaniecowpony]

Glad you found the problem! Did you go with a stock replacement cooler?

Brian,
I had several ways to go, including the Dorman aluminum housing. I ordered a new OEM oil filter housing (w/cooler) and was going to rob the cooler off of it along with the seals that seal the cooler to the housing. Upon removing the cooler from the housing, I found Mopar has revised the housing (again) and now it has a web between the oil and the coolant ports and separate seals instead of the one piece siamese figure 8 seals. So, I elected to go with the newest OEM 68596318AB housing/cooler assembly.

Assuming this fixes my problem (and that's still an "IF"), If this taught me anything about the 3.6L, it's that I'll do oil analysis religiously at every oil change. All you 3.6 folks should do the same.

This makes me wonder if oil dilution is behind the rocker/cam issues of the Pentastar, even after they redesigned these parts extensively.

 

[Maverick909]

Brian,
I had several ways to go, including the Dorman aluminum housing. I ordered a new OEM oil filter housing (w/cooler) and was going to rob the cooler off of it along with the seals that seal the cooler to the housing. Upon removing the cooler from the housing, I found Mopar has revised the housing (again) and now it has a web between the oil and the coolant ports and separate seals instead of the one piece siamese figure 8 seals. So, I elected to go with the newest OEM 68596318AB housing/cooler assembly.

Assuming this fixes my problem (and that's still an "IF"), If this taught me anything about the 3.6L, it's that I'll do oil analysis religiously at every oil change. All you 3.6 folks should do the same.

This makes me wonder if oil dilution is behind the rocker/cam issues of the Pentastar, even after they redesigned these parts extensively.

Keep us posted. These are things I like to keep in mind with the 3.6. Eliminate problems in the future like the rock/cam issue

 

[Byrds8]

I have had a UOA on mine recently. No coolant in my oil. There were various places below, all the way to the support brace, that showed residue. Granted, it was mostly white in nature vs the pinky color of the coolant. Not sure why it would be that way but it was. I happen to find the cap by accident when I was messing with it and got it up to almost where the fan would cut on then I cut the engine off. When I went back to the engine bay, I could hear the air escaping the cap. Wiggling the cap slightly made more or less escape but none the less it was indeed coming out. So far, with the new cap, I have not heard anything else. I will check it again in a few weeks to see if coolant is at the same level and see if there is any new residue.

 

[Rogersocal]

Thanks to this thread I checked mine and have already added 1.5 qts. Of coolant I know there is still some air in the system because I hear it on cold start up so I will take a little more.


So, how do we do the vacuum bleed on the 2.0?

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