Hey guy's: I hate to be dumb, but what controls the pressure in 2003 7.3radiator? I have been looking for mine. I doesn't appear to be the cap on the bottle.
Thanks Jim

 

It is the cap on the degas bottle.

Testing Cap

WARNING: To avoid personal injury, do not unscrew the coolant pressure relief cap while the engine is operating or hot. The cooling system is under pressure; steam and hot liquid can come out forcefully when the cap is loosened slightly.

Remove the pressure relief cap from the degas bottle.
Immerse the pressure relief cap in water and install it on the shallow filler neck of Radiator/Heater Core Pressure Tester and Radiator Cap Adapter, part of Radiator/Heater Core Pressure Tester.
Immerse the filler neck seal in water and install it in the filler neck adapter.
Install the filler neck adapter with the filler neck seal to the Radiator Cap Adapter.
Connect the female quick-connect fitting of the pressure test pump to the male quick-connect fitting of the filler neck adapter.
NOTE: If the plunger of the pump is depressed too fast, an erroneous pressure reading will result.

Slowly depress the plunger of the pressure test pump until the pressure gauge reading stops increasing and note the highest pressure reading obtained.
Release the pressure by turning the relief screw counterclockwise. Then tighten the pressure relief screw and repeat Step 6 (at least twice) to make sure the reading is repeatable within the specifications of the pressure relief cap.
If the pressure test gauge readings are not within specifications, install a new pressure relief cap. If the pressure test gauge readings are within specifications, carry out the cooling system Pressure Test.

 

Yeah i've heard it sound like a soda bottle before. Psst

 

Relief pressure is 16 psi.

 

Thanks Guy's: I realllly appreciate it. Jim