Air pushing though the radiator.. 3406e

what kind of truck? some trucks have a air valve in the sleeper that controls the heater shutoff sometimes it will leak air in to the water side. but if you have a slight miss its more than likely the headgasket.

 

He has a Pete, Freightliners do that.

 

If it's missing and down on power, I'd say the headgasket is a good bet. I had a cold compression leak on my C-15, ran fine when it warmed up but smoked white and ran rough when cold. It was covered under my Escape plus warranty thankfully.

 

no way its sucking air from the rearmain 99% ITS A HEADGASKET if you have elimenated every other posability.

 

i am completely lost at ur comment

 

When bottle testing a unit, the rad cap must be holding pressure or especially in a cat it can draw in air, removing the air compressor discharge line removes any possibility of the air compressor putting air into the system. Draining the complete air system removes any possibility of any valve being in the cooling system that is air actuated leaking into the system. The fan runs on air and without any air in the system you need a remote air source to run the fan. Also if you start off with a cold engine it takes three fan in cycles to purge all the air from the system. If you get air coming out of the overflow hose after three cycles it is from compression.
I have bottle tested hundreds of units, because they are blowing out coolant, twenty percent are because the rad cap is faulty.
People put all kinds of things in their cooling systems to make it better, I have seen multiple units, that the head is removed, and nothing is found. because they knew it was the gasket, it was the cap.
Always start at the cheap things and do the complete test then you know.

 

could it be a injector tub maybe just asking im kinda haveing the same problem myself on a c 15

 

If you have a loose injector in a C15 it will put air into the fuel system. Every time I have ever seen a problem with the injector sleeve it is fuel in the coolant, and coolant in the fuel. It is possible to have compression go past the sleeve, never seen it in my memory, unless the head is cracked.
The sleeve is installed with an"O" ring and retaining compound. Once they are in place properly they do not normally leak.
Just a thought!

 

mine started when i had injector put in a couple months back has kinda miss or stutter to it and bubbles in the sight glass on the fill tank lossing about 1/2 gallon per 2 to 3 thousand miles