Air bubbles in the coolant reservoir

[Tonyrodz]

Never heard of Blue Devil...where did you hear about it @Scottydoggs ?

It's good stuff, not cheap tho. They sell it in parts stores around here.
I even found it on Walmart's site.
https://www.walmart.com/ip/Blue-Dev...pFwJ58OOoYnHeEOcEQCnQxreOyQzbDuxoCzYIQAvD_BwE

 

[swathdiver]

...radiator is new

Is it OE or aftermarket? Remember those aftermarket ones are lacking the restrictor for the system to function properly? If it's not that, then I would suspect the heads or head gasket.

 

[Doubeleive]

Is it OE or aftermarket? Remember those aftermarket ones are lacking the restrictor for the system to function properly? If it's not that, then I would suspect the heads or head gasket.

it's a new oem from the dealer, no exhaust gasses in the reservoir I was checking it for a few minutes even before I made the video fluid stayed nice and bluish color

 

[Scottydoggs]

its sold all over the place. all i can tell ya is it works, unlike all other snake oil bs tar pellets junk.

 

[Rocket Man]

Head gasket sealant or coolant stop leak?

 

[Fless]

have you filled the rad via its cap? id idle it open cap till up to temp, then top it off and cap it.

The OEM radiators don't have caps in these.

 

[iamdub]

Didn't @iamdub's brother's truck have a very similar issue? His was such a slow leak it wasn't even noticeable til it was too late. Think his was due to the 706 heads.

Affirmative. I never got to witness anything (bubbles in the tank, etc.) prior to it's failure and he's not one to know to look for anything to report to me. He told me after the fact that he had been adding coolant since he bought the truck and that the oil pressure had been gradually decreasing over the week or two prior to it losing all pressure. Yes, it was a Castech 706 head failure. '05 LM7.

 

[iamdub]

Unless it's just still working out air from when you replaced the pump and rad, it's gotta be compression gases. You could run it with the accessory belt off to rule out pump cavitation. The common Castech head failure let coolant leak into the top of the head where it would run down the drain holes and into the crankcase. It wouldn't leak into the cylinder or be pressurized by the cylinder pressures. Castech head or not, there's still a chance the head is cracked or the head gasket has failed.

 

[exp500]

I've seen the rear heat plastic fittings leaking a very tiny amount, until it got big enough to shoot onto exhaust manifold and stain it I could not find it. Now I wrap the suspect in TP and if it gets wet it stains or falls apart. Works pretty good if away from fan. Another likely spot is lower radiator hose at water pump, look for stains.

 

[Doubeleive]

I'm going to check it all over again, I just ordered a blackstone test kit because I suspect it's a head but it's not showing any signs other than the bubbles, oil level stays the same and looks normal, no problem other than slow coolant loss.