I don't think I put near that much when I changed the radiator or when I drained the radiator a couple times. I think it took less than two gallons with just a radiator dump. What I was asking was how much would get into the block when filling through the radiator because that thing holds a lot more than the radiator. What I wasn't thinking about when I asked that question was that the heater hoses will allow a lot of air to escape as the coolant fills the block. I just put a gallon and a half in and ran out of coolant so I need to get some more.

 

I think I bought too much coolant. I put about 2 1/4 gallons in the truck and that's all she will take. That's only half of what should fit in there.
I didn't drive it yet but when I poked my head in the passenger window I could hear some gurgling in the heater core while the truck was idling.

Draining the coolant by knocking out a couple freeze plugs was sure to get all the coolant out of the system since they're the lowest point in the system.
All the hoses got hot except for the lower hose which makes sense.
The air temperature was around 55-60º so the fan wasn't pulling in arctic air or anything.
The temperature gauge climbed up to operating temp and stayed there just like it always has.
The thermostat opened a little bit twice in about 30 minutes but that little bit is all it took to keep the temperature pegged on 180º.
The radiator cap was well above the heater core hoses and the truck was at an angle due to the right front tire being up on a hill so I was able to fill the top of the radiator as well as the top radiator hose.
Trying to burp the truck was the same as it always is when I try, the coolant doesn't circulate. The coolant level will drop a little bit but it doesn't take much to close the thermostat back up.

Am I missing something here?

 

It took quite a while to get all the air out of mine. Never had that much trouble with any other vehicle I ever owned, but it appears these trucks have the same issue. When I cahnged out my radiator, I drained everything as well as possible - had rear of truck higher to get out as much as possible. Took about 5 gallons total - coolant and water. Probably spent 2 hours to get air all out with front right corner raised. I also loosened clamp on hose going to core to let air out as well.

 

Since you've got the StuporChip: Get your truck all angled up for a burp, then use the idle set function of the SC to run it up to... what is it, 1600RPM that it tops out at in the SC? or 1900? Whatever, get it there. Run it at that until the thermostat opens, then drop it back to normal idle. At that point the coolant level in the radiator should fall. Top 'er up, and lather/rinse/repeat until the level doesn't drop shortly after returning to normal idle. Then make sure the overflow reservoir is at some reasonable level and call it good.

After that routine, there may be some small amount of air left in the system but it'll find its way out on its own in the next several hours of drive time. Check the reservoir from time to time and top up if necessary. I've only had to add, oh, maybe a pint or so.

All that said: If you didn't remove the thermostat or one of the heater hoses at the engine side, you probably didn't drain the block.

 

I drained the radiator through the petcock valve and did some bottom hose squeezing to get as much as I could out that way and caught about a gallon or so in a bucket then lost probably 1/3 gallon to the ground. Then I popped the two freeze plugs out on the driver side of the engine and it seemed like at least 2 or 3 gallons hit the ground. That mess was draining for a good 20 minutes with a pretty steady stream for the first 30 seconds then a glug a lug type drain for 5 minutes or so until I popped the radiator cap off. I imagine I left about 1/2 gallon to a gallon in the heater hoses and the bottom of the radiator but I don't think it would have left much more than that.

I just looked at the online manual for my tuner, I don't see where the setting is to change idle. I can stick a little piece of wood in between the throttle bar and its stop to bump the idle up a little while I'm standing at the passenger side of the engine, that should be just as good. I'll have to try that.

 

Oops, my mistake. I thought the temporary idle setting was in the 3815 as well as the newer 3865 but I was wrong. Sorry about that.

The high front/high idle trick makes the job go faster even if it's on a vehicle whose cooling system isn't as finicky as ours are. It was a lot easier on automatic choke carbureted engines when you could just reach out and flick the high idle cam into position.

 

I wish the magnum engines were like the 3800 series engine in my old 89 thunderbird, it had a coolant bleed valve on top of the engine. You could crack that puppy open and out came all the air.

 

I don't understand why everyone has problems burping these things. I never had to put mine on any kind of crazy angle to get the air out.

Sheriff does mention the bleeders from other vehicles. It wouldn't be too difficult to scavenge one from a boneyard and install it on the upper heater core line.

 

I've been toying with the idea of quick disconnects on the heater lines so I could run the coolant through the core in the normal direction all winter and backward all summer to keep scale from sticking so readily. One more set of disconnects, a tee, and some way to easily vent pressure (garden hose sprayer nozzle, maybe) could then be stuffed into the top hose to bleed the system of air. Whether or not I'll actually get around to doing it is anyone's guess but with a couple of months of scheduled business downtime coming I might just find the time and inclination.

 

I'm planning to install one of these in my truck and other vehicles for that very reason: Adding a Coolant Filter to the IDI Cooling System There is also an additive to inhibit electrolysis in the cooling system.