I have a new LT1 car and if your LT1 has 70k or more replace the water pump. These sec. gen. engines water pump don't last as long as the first gen. small blocks.
On the newer LT1 car even after replacing the water pump, flushing, new radiator cap, ect. the cooling system would over pressure from the heated water not being able to expand in to the expansion tank and the found that the aluminum pipe going to the expansion tank under the battery was corroded up and clogged . I replaced it and no problems now. No blown head gasket!
You can see the aluminum pipe in the photo. and the copper pipe I had laying around now being used.

 

Are you sure the original pipe didn't get kinked while working on the car? I can't imagine it would corrode to the point of clogging in such a short time.

 

pretty cool fix

 

interesting, and I thought the radiator cap was designed to release pressure

 

It is designed to, which is rated at what, 18 lbs? The radiator cap will let loose at that pressure and spew coolant long before the head gaskets would be in jeopardy. This clogged expansion tank pipe causing blown head gaskets makes no sense to me at all. Maybe somebody can explain how 18 psi in the cooling system is enough to blow head gaskets.

 

Maybe the kinked or clogged line allows the coolant into the overflow but wont let it back into the system?

Coolant going into the overflow would be under pressure, coolant going the other way wouldn't be under pressure.

Car over heats cause of low coolant level in the system and damages the head or head gasket?

 

Camaro69 wrote "The radiator cap will let loose at that pressure and spew "

sounds a lot like me after I eat corned beef and cabbage


yup, I'm confounded as well

 

we call it the "overflow" tank but it's there because fluid expands when warm (think the nonsense global warming people saying Florida will soon be under water)

it wasn't that long ago when cars only had a little rubber hose to nowhere and the expansion would simply drip to the ground. When enough space was created (rad level dropped) then there would be no more little drops. Of course you'd be down a few ounces of coolant.

Now whether it's for environmental reasons or that being down a few ounces is all that important, we have "overflow tanks" and as the coolant cools, it draws back from the tank.

I do not see how once enough fluid "bled" from the cooling system that even if it could not return, how it would damage the head gasket?

But, I also thought my daughter would never bring home some of the boys that she has, so I've been wrong before.

 

Cars today run at a much higher temperature then they did in the 70's.

If the car gets up to 220 or 230 it will push coolant into the overflow tank, when the car cools off a small amount of vacuum is created in the radiator.

This small amount of vacuum pulls the coolant back in to the radiator.

If the hose is kinked, the small amount of vacuum may not be enough to pull the coolant through a kinked hose.

Now you're very low on coolant which can cause overheating, overheating can easily do damage to a head gasket.

 

The coolant going into the expansion tank is under pressure.
When cooling down, the coolant is sucked back into the radiator via vacuum, not gravity. Vacuum = negative pressure, but still pressure nonetheless.