Cadillac Repair: 94 cadillac sls coolant not circulating, cadillac sls, radiator cap

Question
I have a 94 Cadillac sls, it overheats when I drive it but not when it's idling.  I replaced the water pump (twice) and also replaced the thermostat.  at an idle it maintains 7 lbs of pressure.  the coolant is not circulating and does not come out of the radiator when I start the car with the radiator cap off.  Thank you

Answer
With the radiator cap OFF, Increase the engine RPM's to abouit 1500 and see if you can see coolant flow thru the radiator.

NOTICE: BE  careful putting your face that close to the radiator cap opening in case it explodes anti-freeze out the cap opening .