2006 F350 6.0L Head gasket problems...

[robmiller23]

I've got a 2006 F350 with a 6.0L in it, I was noticing that it seemed to be making alot of boost. I asked a mechanic that I know and he pressure tested the cooling system because he noticed some chalky spattered residue around the overflow cap. He said there was a rad cap leak so we replaced that tonight and he pressure tested it again. Now he's telling me that we need to replace the head gaskets because the pressure went from 16 PSI to 18 PSI when he stomped on the gas. Anyone know what sort of pressure you're supposed to be getting when you do the pressure test under load like this? I'm not having any coolant loss or overheating issues so I'm a little skeptical just based on a 2PSI pressure difference. Any help would be appreciated.

[dannyboy950]

A better test would be to get an exhaust gas test kit available from most parts houses.
It has a chemical that changes color when exposed to exhaust gas. The tester screws onto the degas bottle in place of the cap. A 2 pound difference could be just from turning the pump faster increaseing water pressure.

[M90Ranger]

Thier not supposed to exceed the cap holding pressure.
They usually run around 10 - 14psi max.
Excessive boost (greater than 24psi) will lift the heads if you have stock bolts.
If it's not smoking white, the fan clutch and t/stat were checked and are OK, and the coolant flow is OK, I would say you need head gaskets.
Also fix the boost issue or stud it.