i own a repair shop,,and what it is doing is i think its discharging compression through the heater core,what causes this is a blown head gasket,in the water jacket area,on it,and it sounds like a big whish noise when it does it,,i have only seen this happen a few times in my career,,but it does happen to some vehicles,,,it may have busted the heater core too on it,,if all the fluids look good in it rule out the head gasket,and look for a loose line or something under the dash area,but from what you have said it sounds strange,,check all the the levels of every fluid on it,and see if its full of everything,then ry seeing if it has a lot of back pressure on the radiator hose after it runs for just a minute or two,,if it does it has problems,,good luck i hope this help,s.,PS if you can see the top radiator hose swelling up on it it has a blown head gasket,,be care full and good luck.
Its sounds like a vacuum leak or door that opens by a vacuum that is closing or opening as you crank the engine, I've had several new GMC and Chevy's SUV with the similar problems, they are vacuum problems. A blown head gasket will cause the engine to run hot and where the oil is added it will usually be a white milk color there. A blown head gasket will also cause a lot of white smoke from the exhaust when its running. To be sure just run a compression test or easier run a vacuum test when you get it started again. Good luck and GOD Bless,