Cummins isx puking coolant

Here we go again... What caused the head to fail the first time around? And let me guess, they removed your old head and slapped a new one on with a new gasket and told you to have a nice day? Correct?

 

To test the air compressor remove this big nut and place a quarter in there and re-install nut. Start motor and see if you have any coolant/air build up in the cooling system. If you have air/pressure in the system with the quarter in there, it is not the compressor.

I would also go to NAPA Auto Parts and purchase a Block Test Kit, around $50. If you have exhaust gas in your cooling system it will let you know in a minute or two.

 

They never diagnosed it properly, which would have entailed dropping the pan and barring the motor to look for coolant on the cylinder walls. The heads rarely fail on their own on these Cummins, it is normally a fretted liner that takes them out. It scores the bottom of the head which is what causes the failure, and your symptoms.

 

Here is what you look for, I took this photo of my motor just prior to in framing it...

 

Here is the underside of the head, see the mark, that is from the liner, it scored the head as well as ruining the gasket. It does not take much. #5 cylinder seems to be the one that normally breaks lose.