Ok, when my engine is running, after about 5-7 minutes, water starts coming up at the middle "dimple" where the valvecover/head meeds the intake manifold. quite a bit of water is coming up there and its boiling. I am affraid I know what the problem is but I wanted to get some 2nd, 3rd opinions. Also, are there water passages that run through the intake manifold like on the old SBC?
Please help

Thanks

Edit - Also, the intake manifold/fuel rails are too hot to hold on to. Is this normal? This is actually the first time I have gotten my engine running since i got it outta the junk yard.

 

LS1s use a dry intake. No water passages at all.

 

No water through the intake.

do you have any pictures of this?

 

So am I looking at a blown head gasket or craked head(S)? And sorry, no photos. Basically it looks the same as when there is a crack in a radiator and water is boiling out of it.

 

Sounds Like an Internally blown head gasket. Blown inside the cylinder around the combustion chamber.

Could also be cracked head.

 

 

Definitely could be a fracture in the head. I'd say it's time for some disassembly.

 

Im leaning towards blown head gasket beside the piston.

 

could be blown head gasket, cracked head, or the coolant line the runs under the intake manifold, my coolant line was leaking, but i dont remember any coolant coming up through the chanles, but it would run down the front of the engine and filled the holes were the knock sensors are.
i just cut it out and sealed all four of the ports , and the radiator port off.
it is just there to warm the intake up, since it is a composit intake it dose not have any coolant running through it.
hope that helps, good luck

 

The coolant tube is there to bleed air out of the block and heads. Do not block it off.

 

That was it! I had it plugged - amazingly enough.. it doesn't happen anymore. It seems weird to me that a gasket could re-seal itself after it was leaking. I'm just relieved. Thanks for the insight!

 

cool thanks, i did not know that it was also for air bleed off,
i guess it makes since.
thanks 2xls1.
can you block off the back ports and steel have the front ones hooked up
to the radiator,will that work?

 

That is the way all 01 and newer LS1/LS6 are set up. Plugs on the back and a pipe on the front. I believe there has been one person that said he blew a freeze plug out of the back of his head when he blocked off the pipe.

 

just an update - I pulled the intake manifold last night, and cleaned out the massive amount of mud up there, and realized the water got stuck in the valley when I powerwashed the engine. I also found one of the valve-covers is cracked. So the water boiling up was just from extra water that never came out of the valley after a good cleaning.

Thanks for all the info!