I'm getting pressure in my coolant reservoir. So much so that it's pushing coolant past some of the hose clamps and out of the coolant cap. I've replaced the coolant cap as well as the reservoir, so I know that's not faulty.
I was told that the only thing that could cause that is a bad head gasket causing exhaust to pressurize the coolant.
Is this true?

 

Yes, it's true.
You can test to see how fast the pressure builds, but still the cap is the limiting factor. I run with my cap "not so tight." My leak isn't too severe.
Ed

 

Have you been able to loosen the cap and use the car even though the exhaust is pressurizing the cooling system?