Thermostat?

[6.0DJ]

Ok I flushed my friends 04 6.0 and refilled it with ELC coolant yesterday. We found the cap was faulty while we drove it around circulating the flush in the system because it was leaking from under the cap and the upper and lower radiator hoses were holding pressure.

Well today neither hose has pressue in them, the resivior is full of boiling ELC but, the engine temp is normal.

Is the thermostat stuck open?

Thanks

[jesilvas]

If it was stuck open, then it wouldn't ever hardly warm up.