[J_thomas675]

I have a 2011 Denali hd has 198xxx miles tuned and deleted 5” straight pipe. Couple months ago after a 300 mile trip when I got home it popped up a said add coolant so I checked under the hood and it was between “min” and “max” so I didn’t add any at the time it stopped saying add coolant. Well now it popped back up and under the hood it was sitting on “min” truck had been sitting 30 min to and hr and the tank had a lot of pressure on it but when the pressure was released the coolant came back up to “max”. So I drove it last night and this morning I went to squeeze the upper radiator hose and it’s not hard still pretty easy to squeeze but the coolant tank had a little pressure not much at all. Could I be having HG issues? Just not sure why the coolant level goes up and does so much

 

[NHfireDmax]

Anything is possible. An oil change or simple analysis Blackstone labs on line . its nice and inexpesnive...

could be a minor leak... the coolant / heater core lines have a plastic compression fitting so to speak at the fire wall and the main octopus line from the lower rad fitting...

When hot the expand and seal, when cool, they can seep... my 2013 started and was hardly noticeable at first... not sure your location, but the cooler the nights the more may seep out. check under the truck in the am... just in front of the oil pan, along the front plastic skid plate and also run your fingers around the heater core lines and see if they feel wet

 

[J_thomas675]

I’m in bham al added some coolant and drove about 100 miles and the add coolant hasn’t popped back up it’s normally kinda random, not sure if it’s just cause the temperature has gone down in bama but I did noticed truck is running really cool usually sets at 210 but could hardly get it to 210 on the dash