Waterfall sound in dash at startup

[taze]

On 12/10/2025 at 7:37 AM, tjonesdfw said:

Back to another dealer next week with the same issue again... waterfall sound at startup, about an inch low in the tank, and the smell of coolant around the front of the truck every time I stop. Hoping this new dealer properly diagnoses, because in my mind there has to be a small leak somewhere.  

I can smell this post.  Hope they get it fixed right!

[tjonesdfw]

Ended up being a seep in the stupid plastic end cap on the radiator, so new radiator it is.  4 years and 70,000 miles and she's already needed 4 camera modules, multiple cameras and wiring harnesses, a new rear sliding window, ball joints and now a radiator among various other little items... not looking forward to the next year or two at this rate.  

[Kev2lee]

That’s a bummer, sorry to hear.

i have a 2019 5.3l (new body) and a couple days ago, after turning off my truck, the radiator fan kept blowing for about 2 minutes. It continued to do it the past several days and now it’s leaking a ton of coolant. One mechanic said new radiator, going to another today. Can’t tell where the leak is coming from, was hoping it was the cheap clips they use to connect the hoses due to the amount of coolant leaking. 
just last night I heard the “waterfall” sound when I turned off the truck…. So I have some air in there now.
I guess the plastic they use now of days on the sides of the radiator is some cheap stuff. Probably going to upgrade the radiator.

I have had zero issues with my truck since 2019, only 31k miles right now and this is the first problem.

 

anyone have any issues with transmission slightly slipping while slowing down?

[tjonesdfw]

35 minutes ago, Kev2lee said:

That’s a bummer, sorry to hear.

i have a 2019 5.3l (new body) and a couple days ago, after turning off my truck, the radiator fan kept blowing for about 2 minutes. It continued to do it the past several days and now it’s leaking a ton of coolant. One mechanic said new radiator, going to another today. Can’t tell where the leak is coming from, was hoping it was the cheap clips they use to connect the hoses due to the amount of coolant leaking. 
just last night I heard the “waterfall” sound when I turned off the truck…. So I have some air in there now.
I guess the plastic they use now of days on the sides of the radiator is some cheap stuff. Probably going to upgrade the radiator.

I have had zero issues with my truck since 2019, only 31k miles right now and this is the first problem.

 

anyone have any issues with transmission slightly slipping while slowing down?

The waterfall sound is typically just created by air pockets in the heater core, cased by low coolant, not a leak inside the cab.  From what I’ve seen, most of these radiators fail at the plastic end caps and seams, so check there first.