M925a2 8.3 cooling system burping

[Will47]

I keep seeing mention of burping the cooling system on the 8.3 Cummins when filling with new coolant. How do you burp the system?

 

[juanprado]

One way is to turn on the heater and use the drain petcock on the heater core.

 

[Will47]

So the truck would have to be running correct?....I'm guessing the air would go to the highest part of the cooling system....that being the heater core

 

[juanprado]

yes on running and unlike some civy vehicles there is no bleeder screw on the water outlet.

 

[Jolopicus]

One way is to turn on the heater and use the drain petcock on the heater core.

Something tells me this will also help when the heater core is not getting overly warm or blowing really hot air. If your heater core is mostly full of air that would explain it. Nothing else it's great to know that to try to blow out the heater core of the spring if I think they're sediment in there.

 

[juanprado]

On the m939, the heater core is a great place for funk to accumulate if not flushed out regularly. First time, I flushed it, I was amazed how much "mud" came out.

 

[Jolopicus]

It just never occurred to me in the 40 years of being a Minnesotan, until I bought a super clean 2011 Liberty for the wife, and found the core was just full of sediment. Quick flushing with some well-pressurize water and boom, back to high heat. Same kinda thing I suspect in my new toe m939. Will see in the spring and report back.

 

[juanprado]

I just thought it was sloppy casting clean up from the block. I had not seen that in a civy vehicle.