Coolant level should be inside the crosshatched area when the engine is at its normal operating temperature. If the engine was cold in the picture you probably dont need to add coolant but check when the engine has warmed up to be sure.

 

Always best to refer to the owner's manual to ensure you don't give incorrect info. The OP's coolant is low and is not supposed to be below the crosshatched section at any time.

 

Owners manual says to ensure it's filled to the cross hatched section pointed to by the arrow when cold.

Might have been undetfilled at the factory or there was an air void or two that resolved itself resulting in a lower level.

 

Fill it up and then you need to purge the system. On my 22 Silverado there’s a procedure in the owners manual that details how to do this. Since the water pump is electric it can be done with the engine off and key/power in accessory positions

 

I noticed on mine 24 trail boss, every now and then I can smell coolant, but no leaks on the ground or engine compartment, the level has gone down a little, I have 4011 miles right now

 

I haven’t noticed a smell of coolant with mine but also not really sure what that would smell like. Haven’t noticed any smells that seem unusual. But I’ve also had to top it up twice in the last 6 months. No signs of leaks and engine runs fine. Who knows….

 

 

Yesterday afternoon, I noticed something wasn’t quite right. When I went to grab lunch, the heat in my vehicle wasn't coming on at all. The coolant temperature was high enough that I expected hot air, but instead, it was blowing cold. It finally worked on my way home last night and again this morning. But after returning from lunch, I just checked the coolant level—it’s completely empty.

I’m supposed to head back to Texas from Nevada this weekend or early next week, and this it the last thing I need to worry about while towing my camper halfway across the country. I’m concerned that taking it to the dealership here could take forever. Maybe I should just keep it topped off? Or maybe I’m just being paranoid, haha.

 

Eek! Well, regardless of what you decide to do, definitely top it off with some DEX-COOL and keep an eye on it. Also check for leaks (I see some weird streaks on the inner fender?) and see how quickly the level drops. If it's a slow leak somewhere then it might be hard to find, but if the level drops fast (after topping off, running it, letting the air purge, topping off, rinse and repeat until the level doesn't drop anymore) then it should be obvious where the leak is.

The dealer shouldn't have much difficulty finding the issue if it's big enough, mainly doing a pressure test to see if and how big the leak is and then trying to locate it. With that much coolant lost I'd be very surprised if there's not evidence of the leak somewhere. Good luck and keep us posted!

 

Technicians found that the upper radiator hose was leaking at the radiator. They didn't have the part, so I'll get it fixed when I get back to Texas.

 

 

Seems I have the same issue and location.
Do you know what was replaced?
Im 1,500 miles past warranty so will be fixing myself. Adding coolant and will monitor to get me home.

O

 

And the last few days, I've begun to smell coolant. Thanks for the pics, going to check to see if that's what I have going on.

 

It is a shame that fairly new trucks are having these issues, that are usually associated with a vehicle with 100k or more.

The parts situation is horrible. Never in my life would I have thought that you could go through 5 brand new defective parts but I now see it all the time. Even dealer said they have gotten brand new defective parts.

All the YouTube engine channels are also experiencing this. One even got a defective engine block. Nobody noticed it until brand new engine failed. It was found during the teardown. Can't fix a defective engine block unless you have a complete welding shop/machine shop. It's like people everywhere can no longer do the things they used to do or simple things that were common place.

 

I have the same issue. We have two ‘24 AT4s, each with ~30k miles on them. Build dates 4/24. Both leaking from upper radiator hose connection. Mine goes in tomorrow morning for diagnosis. They wouldn’t just order the hose for me. 😒

 

Went to the dealership yesterday, and wasn’t thrilled with the experience, but that’s a long story. Anyway, they ordered the hose after making me wait two hours to determine exactly what I told them was wrong. Hose is on backorder with no ETA. We have two trucks needing this repair.

 

So, elsewhere on the site a GM member gave me an ETA of 12/25-1/1. I’m at the dealer right now for oil change, so checked with parts guy. His info says backorder, none in the country other than what other dealers have on hand(which is very little). One of the dealers even had a note on their contact like that reads “WE DONT HAVE THIS PART, PLEASE STOP CALLING!!!”
I think this is going to be a widespread issue. Lol.

 

I am having this exact issue and what’s frustrating is it isn’t all the time. Have you resolved it yet? At the moment I am monitoring it daily. Some days it leaks, most days it doesn’t. Maybe cold temperature related. I am just topping off the coolant levels until I can get a hose. I have 40k on it.

 

Wow, I was really fortunate that the dealership I was at had a used 2023 Colorado. They ordered the wrong part, and got the okay to cannibalize from the used truck. Figured GM would have considered this some kind of recall.

 

Mine was low from the factory. I noticed it and had the dealer top it up. Fill level information is in the manual

 

I fixed my this week. I found a video on YouTube that shows how to do it. Link here:

I don’t think he knew the leaking only happens when cold. But he shows you how to change the O ring. I did it Thursday. Friday was really cold in the morning. Drove it around a lot and no leaking at all. It is an easy fix. The factory O ring is flat and made of rubber. I wonder if being rubber, it’s degrading from the chemicals in the coolant? Not sure, but mine is fixed now with a little ORing. He says to use a series 218 silicone O Ring. Took maybe and hour total to swap out.

 

I have been smelling coolant and I just received the pack of silicone 218 orings. Do I need antifreeze before making the swap? Will a lot be leaking out when the hose is pulled?
Thanks for the help.