Ok here's what i have done. i ran the engine for about an hr with the cap off and let it get to temp. i hooked up the pressure tester and let it build pressure till it hits 16 pounds and it takes roughly 4 min to get up to pressure. now i have checked around for caps and they say 16 pound closed sysem and i looked at the cap i have and it says 15 pounds.. man oh man if thats the problem im going to kick my own butt for not looking at it since i did after all buy it from a chevy dealer when i got the new t-stats

 

Seems to build pressure very quickly.

And having a lot of pressure is not ideal,pressure is used to raise the boiling point of the coolant,1psi increases the boiling point 3 degrees.

15 psi is more than enough and I would be concerned why it is building so quickly-cracked head would be my guess.

 

if i let it run for about an hr and get up to temp and after the electric oil cooler cycles a few times i pull the cap and put the pressure tetster on it is when it takes around 4 min to get to 15 pounds. i checked and it calles for a 16 pound cap and im running a 15 pound cap

 

Go ahead and change rad caps but I doubt 1 psi will solve the trouble.

 

makes me wonder.. i mean im not losing a large amount of coolant or all the time and it didnt start this till i had the injector pump replaced along with the rad water pump t-stats and cap

 

ok so it sat for 24 hrs with 15 pounds on it and it didnt move an oz. i filled the tank with coolant and started the truck and it took about 30 min at idle to get the t-stats to open and get it up to temp. i then put a gallon jug under the blow off tube from the tank and pulled the lever on the rad cap and it pumped out about 1/8 of a gallon so i let it sit for another 30 min and when out and pulled the lever on the cap again and all that cam out was so air. so i shut it off let it completly cool off and opend the cap and no pressure. i then took the glow plugs out 1 at at time with 15 pounds of pressure in the system no pressure loss and no coolant comming from the glow plug hole so i dont have a cracked block. so im going to drive it around for the next few days with the new cap and see what it does