Changed out the coolant (AOT) on my 13 Ram Hemi yesterday and all went well. Petcock/spigot is on the lower left of the rad on this truck. Took a 10mm Allen key. Attached hose and ran to a rad collector pan. Initially about 4-5 liters came out then it just turned to small trickle with a bunch of bubbles. Not being in a hurry at all, even though I was tempted to close it once it was just a trickle, I just let it run. After about 5-10 minutes of farting around in the garage I decided to check it again. While looking and still seeing the bubbles/trickle, I got a sudden flow again with at least another 4-5 liters that came out so I assume some type of vacuum/airlock let go and allowed this to happen? After seeing that, I was thankful I didn't close it prematurely. My driveway has about a 30 degree slope to it towards the road so that is how I decided to drain it, with the slope and the front of the truck pointed towards the road rather than sitting level. (May have helped with the second surge/getting more out of it?) Refilled with a 60/40 mix of $54 dollar a jug Mopar OAT coolant from the dealer, started vehicle, turned heat on high and just squeezed the upper rad hose and added more coolant as needed until no more air came out after it got hot. A couple shorter drives here and there brought it down maybe a half liter total but all seems good now. I will keep an eye on it for a week or two though just to make sure.
