Andy fortner

iTrader: (1)

i got a 6.0 370ci it has tsp ls6 head all arp bolt brand new cometic mls head gaskets arp head studs motor runs good but its building pressure in the radiator the car is not running hot i mean u can let it set for 2 or 3 days and go out ther crank the car and in a matter of seconds it will blow hoses no whater in oil so im lost done did all i no to do other than get some more haeds and try that can yall help thanks

JPH

iTrader: (2)

How tight did you torque your heads stud nuts to? Any spray sealant on the gaskets did you use? Block/head finishes look good?

Andy fortner

iTrader: (1)

i tighting them to arp spec i think like 80 or 85 yes i used Copper SPRAY the block and head looks good going to get head checked for sure tho in the moring

JPH

iTrader: (2)

Looks like you did it correct. If the head checks out ok, inspect the block. Otherwise I would order new set of gaskets or try and clean/reuse your current cometics and prep them a tad different next time. Was the gasket bore larger then the chamber of the cylinder head?

Andy fortner

iTrader: (1)

no it was a 4.30 bore gasket same as motor

JPH

iTrader: (2)

4.300? Do you mean 4.030? What heads? Rule of thumb is gasket bore should be .030 more then what the engine bore is. 4.030 bore +.030=4.060

Andy fortner

iTrader: (1)

ya 4.030 and the gasket are 4.060 my bad

JPH

iTrader: (2)

That is checks out good to.

Andy fortner

iTrader: (1)

well took heads to shop to day and pressure checked them they was good head gasket was good checked top of block it looked good so i put it all back togather well got it back running well no luck same thing well i took belt off to see if it may have something to do with water pump wit still same thing so next i took Thermostat out and put belt back on well it help some but still builing pressure in Coolant

JPH

iTrader: (2)

Darn. What kind of boost psi are your running again?

Andy fortner

iTrader: (1)

10 pis but it dose it when its at idle only thing i can come up with is the block is cracked some where but makes no cents cause ther is no water in oil

87silverbullet

iTrader: (11)

The cylinder wall could have a slight crack in it. A crack in a cylinder wall would not show water in the oil but it will pressurize a cooling system.

JPH

iTrader: (2)

check between #3/5 and #5/7 cylinders for any sides of cracks.

Andy fortner

iTrader: (1)

i did but did not see anything well i got a coolant pressure tester i got 26 pis on it to see if i can find any cracks or get some cule of whats going on but ya i kinda thinking somthing wrong with block but i have never seen a lq9 or 4 block craked but its my kinda of luck i will have one

87silverbullet

iTrader: (11)

26 psi is nothing compared to the cylinder pressure of an engine.

You might have to pull it and magnaflux the block.

wildcamaro

iTrader: (15)

I know this is a dumb question, but do you have a line from coolant steam plugs on head to radiator or a line from water pump to rad? That could be you over pressure coolant system if not, figured I'd throw it Out there

JPH

iTrader: (2)

Good idea. It's gotta be something simple I would say. (I hope)

wildcamaro

iTrader: (15)

I know this is a dumb question, but do you have a line from coolant steam plugs on head to radiator or a line from water pump to rad? That could be you over pressure coolant system if not, figured I'd throw it Out there

Andy fortner

iTrader: (1)

yes i have a hose from the head to the radiator

wildcamaro

iTrader: (15)

is it a line from the front coolant bypass crossover? or do you have it running straight from head?

Also i have seen excessive coolant pressure caused by a bad radiator cap...i know its simple but it DOES happen...

I always approach things with the KISS method, and then if that dont work i got to the more in depth reasons it could be acting up...

Good luck man, hope you get her fixed...