SBC coolant overflowing

I'm thinking it is a head gasket but what else could cause a SBC to force coolant out of the overflow when it is operating.

Is it over heating, or just getting coolant were coolant doesn't belong?

If its just puking out of the tank, it could be the cap went bad. Happened to me.

It's not overheating, I did swap the cap (for another used one) and it stopped for a while, but started again once I was on the road.

I have noted my upper hose has a kink in it, could this have something to do with it?

Kink as in, pinch off the water in a garden hose, kink?

If yes, then replacing that or at least figuring out why its kinked would be were I'd start.

If you can, pull the radiator cap off and start her up. Let it idle. If it's bubbling or burping, that's definitely a head gasket. you can also usually smell exhaust mixed in with the coolant smell. I would DEFINITELY unkink the hose first. That can make it overflow if it's really shutting down flow.

Hope that it is not a cracked head.

iceracer wrote: Hope that it is not a cracked head.

yeah, some castings had issues with cracking across exhaust seats.

are you sure you got all the air out of the system when you filled it?

i'd start with a new cap.

Damn it, I shortened the hose that had the kink in it and it is fine now. Then I pondered the world and my dilema, then it hit me, the dang hose on the overflow cap was on backwards, sucking fluid from the overflow, swapped it out and no more overflow problems, at least it was cheap.

Took it for a nice drive today, it was sweeeet

Nice. I wish my car issues were this simple.

aussiesmg wrote: Damn it, I shortened the hose that had the kink in it and it is fine now. Then I pondered the world and my dilema, then it hit me, the dang hose on the overflow cap was on backwards, sucking fluid from the overflow, swapped it out and no more overflow problems, at least it was cheap.

does this overflow hose have a check-valve in it?

It is sourced from another vehicle, it has the single long tube under the overflow tank cap to the inside of the tank which goes into the fluid, the tube that vents to the atmosphere picks up the fluid from vents under the cap, does that make sense?