Coolant issue

Remi Bugnon · October 9, 2022

Hey all,

I have a 2014 Sierra Denali 6.2.

I have a cooling fluid problem and I can't seem to find a solution.

When the engine heats up, it makes noise in the cooling circuit, like bubbles and you can feel it in the pipes. Only when the engine is warm.

The cylinder heads were dismantled to change the tappets which made noise.

I've done 3000 miles since and never needed to add coolant.

It's like it's badly purged or too hot but it's only at 200.

It continues to do so for a few seconds when I turn off the engine. I changed the water pump and the thermostat but no changes. I can't find a solution.

I can post a video

Thanks

evad · October 9, 2022

this is gonna sound weird but see if your cap on the overflow tank is venting ... the bottom of the cap should be tight but the top needs to "wiggle" so it can vent ...just an idea to try

Remi Bugnon · October 10, 2022

Thanks for answering, it seems weird to me but I just try to make it hot with the cap a bit open and it not seems to do that. I will order a new and let you know if it solve the issue.

Thank you

SeekAndDestroy · October 10, 2022

Head gasket installed backwards or upside down could cause this. It is easy to get them mixed up side to side or upside down. Has to be the right way or it will block coolant flowing into the head

Remi Bugnon · October 10, 2022

36 minutes ago, SeekAndDestroy said:

Head gasket installed backwards or upside down could cause this. It is easy to get them mixed up side to side or upside down. Has to be the right way or it will block coolant flowing into the head

It's possible I've done that but not sure to have seen any side on the gaskets. Can you tel me if it seem right? I have a pic

Remi Bugnon · October 10, 2022

It seems good like that, have done head gasket many time but not on those trucks

evad · October 10, 2022

i tore one down last year so its been a while but i didn't think you could install them backward on the lt ....but ?????

SeekAndDestroy · October 10, 2022

2 hours ago, Remi Bugnon said:

It's possible I've done that but not sure to have seen any side on the gaskets. Can you tel me if it seem right? I have a pic

I can see in the pic it’s backwards. It says “front” on the right side, facing the cab. The front of the engine is towards the grill. You have to turn the gasket 180 degrees, and flip it upside down. So where it says front will be towards the fans, and you won’t be able to see the word “front”. It’s blocking a coolant passage causing that symptom

Remi Bugnon · October 10, 2022

Just realize it regarding the picture, don't how I've done a so stupid thing..

I'll change them and let you know. Thank you

Remi Bugnon · October 18, 2022

On 10/10/2022 at 10:27 PM, SeekAndDestroy said:

I can see in the pic it’s backwards. It says “front” on the right side, facing the cab. The front of the engine is towards the grill. You have to turn the gasket 180 degrees, and flip it upside down. So where it says front will be towards the fans, and you won’t be able to see the word “front”. It’s blocking a coolant passage causing that symptom

You where right, I just changed the head gaskets (again...) and it works fine. Was really stupid but I've learn something. Thank you

SeekAndDestroy · October 18, 2022

11 hours ago, Remi Bugnon said:

You where right, I just changed the head gaskets (again...) and it works fine. Was really stupid but I've learn something. Thank you

You’re welcome. I’m happy that it is fixed!