2018 JLUR, engine light, aux battery error, cooling issue....need help.

[wudworkr]

I have a 2018 JLUR with 63k miles and multiple issues recently. I had been having issues with the aux battery error light, I have since removed the aux battery and attached the positive aux cable to the main battery positive and same with negative and taped up other ends. Aux battery is now removed. Periodically I still get the aux battery error light coming on. Charging voltage is 14.5v. Next issue is I noticed the engine was getting warm, upon investigation I noticed the coolant reservoir was low so I added about 1/2 gallon. Next day, same thing and I added another 1/2 gallon. I looked all around and could find no visible signs of leaking. Final issue is engine light came on with P0305, cylinder 5 misfire. I cleared the code and all was good for a day then it came on again. Upon start up cold I notice that the engine runs rough for 45-60 seconds then smooths out. Today I had to add another 1/2 gallon of coolant.
I'm not sure any of these issues are related or not and not sure where to continue troubleshooting. With the cooling issue and P0305 I was thinking maybe I had some coolant getting into the cylinder so I did a test and it showed that no combustion gasses were in the coolant. I also did an oil change today and no signs of coolant in it.

Really stuck at what to try next any thoughts or ideas would be appreciated.

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[Stetson]

Sounds like you have 2 or maybe 3 different issues. I suggest trying to isolate them and deal with them one at a time.

The engine coolant loss appears to be the worst issue of the 3. I am not exactly sure what intervals are you added the two half gallons. But loosing a gallon of coolant is a lot! With it running and a good light just inspect every hose, fitting, the underside of the hood, the fan (for splatter). Try and get under it and see if you can find drippings. Maybe smell all around for that sweet coolant smell. The coolant is going somewhere, just gotta figure out where.

Hopefully you can find an external leak, that is the best ‘problem’ because then you can just replace the hose or whatever is the issue.

if the coolant is not leaking externally, then it is leaking internally. It has to be going somewhere and I would guess it is going into cylinder 5 and Causing your rough idle at start up. If the head gasket is bad then it is also causing it to run warm as well. You said the oil looks good, so that is a bit of a mystery. Usually you get the chocolate milk look if it is leaking into the oil and then blended with the pump.

you might try and get a compression test done. If you have different pressure in your cylinders that could be a sign of a head gasket.

your third issue is your aux battery. I am not an electrician. I got some weird things going on with my Jeep so I went ahead and replaced both batteries and the weirdness went away. This is probably the least of your worries at the moment. I think your coolant loss and miss fire problems are likely related and are about to cause you a lot more problems.

do you have any additional intel you can share?

Stetson

 

[Swagger]

Sometimes the aux light comes on to let you know the ess has been disabled due to a misfire issue. This happened to me when an engine oil leak fouled the o2 sensor connector, causing the ecu to think the cylinders on that side of the engine were running lean. The ecu dumped lots of Gas into those cylinders, which caused those cylinders to misfire.
A coolant leak might do the same thing. Look at the o2 sensors for evidence of fluid leaks. Good luck!

 

[Fatfreewilly]

I'd say pressure test the radiator/cooling system with a tester and see if any obvious leaks. Those testers you can rent for free at like Autozone/Advance. You can pressurize the rad and see if it hold pressure. If the pressure starts to drop, look for obvious leaks.

My guess with what you're describing is a head gasket leaking coolant into cly 5, but it's hard to know for sure.

Is the coolant bubbling at all?

If it's the 3.6, coolant can also leak from the oil cooler buried under the intake and be hard to find as it burns off.

Good luck!

 

[mwilk012]

Sounds like you blew it up boss

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