LB7: New here and need help/info PLEASE

merlot

Just what I need
Aug 8, 2014
18
0
0
Connecticut
Hi Thanks for reading I hope someone has Ideas
I just pulled the heads off a Duramax LB7 for the first time and I know many of you know its a fair amount of work ,I was getting pressure in my cooling system so off they came I had them surfaced and bought a head kit with victor reinz head gaskets and ARP studs I took my time cleaning surfaces and did a three step torque ending at ARP's final spec of 125 ft lbs let it sit over night and re-torqued it I put it all back together and its still pressurizing the cooling system almost immediately within a couple minutes I went to take the cap off the cooling tank and it blew all over from pressure and a steady flow of air kept coming out ? what could pressurize the cooling system ?

one idea some said was air bound and causing a boil pressure ?
another said injector cup not seated ? what do I look for/check

any ideas or what you found/heard with this situation and cause or knowledge would be very much appreciated and Thank you guys :thumb: