I have a 91 si with a with a rebuilt 93 vtec head. It has JE pistons bored .20 over with 11:1 compression. I'm breaking it in and I haven't taken it over 3500 rpm. If i drive it for a distance the overflow starts to bubble and my water slowly comes out but the guage say that it is not over heating. Unless all the water is gone and then it will start to over heat. It has new waterpump, new thermostat, and new radiator. There are no leaks anywhere. The fans cycle like they are suppose to. Somebody please help?

 

Sure the thermostat was put in correctly?

 

Yes. I even took it back out just to make sure. The weep hole is clear. I even cut the little tab in the weep hole out today. I drained the radiator and refilled it. There is no air in it. The overfolw just keeps filling up until the water overflows out of it.

 

try letting it idle and turn on the heat so it will open up the heatercore or how does ur radiator cap look?

 

try letting it idle and turn on the heat so it will open up the heatercore or how does ur radiator cap look?

 

The cap looks fine. Do I have to turn the fan on because i turn the temp knob to hot and let it idle today?

 

hate to say it but your head gasket might be leaking compressed air from the cylender into the water jacket

 

If everything else seems to be new and works correctly Im guna go with the Head Gasket. I hate to say it but that sounds like the issue.

 

I hope not I just put the damn thing together. It makes sense though. Could this be from higher compression. The motor is suppose to have like 11.1 compression with the JE pistons that are in it.

 

The compression shouldnt have anything to do with it. I know some of the head gaskets are hard to tell what is the top or bottom. if its not on right it wont seal correctly.