Trapped air in 2.3L coolant system
Recently obtained an 04 Ranger in pretty good shape, just doing routine work on it to bring it back to life and I figured I'd do the coolant today.
It wasn't too dirty but I figured I'd change it anyways so I drained the radiator and pumped out the fluid from the reservoir. I filled up the reservoir with water, about a gallon, and the engine sucked it up just fine, then it stopped after the first gallon. I ran the truck for a good 15-20 minutes, trying to burp the hoses by squeezing them and revving the engine a bit, but the coolant level is just not going down. I only have maybe 1.1 gallons in the truck now but it calls for 2.55.
Is it just random coolant that was leftover in the heater core and engine or is it air? If it is air, anyone have any suggestions on how to bleed it?