Troubleshooting Low coolant on 2016 LML

KRATOCT

New member
Aug 22, 2011
23
1
3
I first had the "low coolant" message pop up on a trip to Colorado from MI about a month and a half ago. The goal was to just drive the truck out there but my friends 6.0 broke down and I had the only other truck capable of towing the 29' camper through the mountain passes to get to the mountains to hunt. At one point on the first pass, I noticed my EGTs climbed to 1350-1400. I let off right away and hopped over to the slow lanes and was able to keep them no higher than 1100 the rest of the trip. The EGTs couldn't have been above 1300 for more than 10-20 seconds, if that. I have the CTS3 with the EAS probe in the exhaust manifold so the numbers should be accurate. Later in the trip just putting around the mountain 2 track trails unhooked from the camper, the coolant message popped up for the first time that I've seen. The truck sat most of the rest of the trip while in the mountains. The coolant level was ok and everything else looked good before coming back. Once back to MI, the truck sits most of the time while I drive the company truck. Coolant was about 1/3 of a gallon below the MIN line on the engine side so I topped it off and changed the oil to look for milky oil a couple weeks ago and every time I do get the truck out 10 miles down the road to go hunting and back, I'll check the top/front big coolant tube the next morning and I'm always able to squeeze it, its not rock hard.

I don't fully understand how the twin chamber coolant tank works or what level the fender side should be at. I want to properly fill the tank. The fender side is currently very low if not empty (I'll have to check later tonight). Even after filling the engine side, it too has dropped again a couple inches below the MIN line. With all that being said, I need to determine where the coolant is going. Truck sits in a garage and I never have puddles or drips and I don't ever smell much when exiting the truck, maybe just a faint coolant smell.

Looking for info on properly filling the tank AND locating the leak. (Any common places to check?)
 

$chultz38

Member
Jan 22, 2009
230
5
18
More than likely you have head gasket issues if you can't find a leak with a pressure tester. Don't believe me put a rag between the inter fender and the overflow tank at the vent of the tank. Drive the truck as normal and see if you find antifreeze on the rag over time. The fender side shouldn't have much antifreeze in it because its just a catch tank. The engine side should be filled to the full line and will fluctuate with engine temp.