Coolant spraying... What is going on?

[dhirocz]

Got a pressure checker? Start it with it installed and cold, and see if the pressure spikes over the rating on the cap. That should indicate if your cooling system is being pressurized from elsewhere.

While some fluctuations in cooling system pressure based on the water pump flow vs RPM are understandable, in general the system should slowly rise in pressure due to thermal expansion.

Does it spray like that or gush out of the overflow if you started it cold, with the cap off?