ISX-15 pushing coolant out of reservoir tank -help-

[Brock]

With the air compressor I'm not sure what signs of coolant your looking for.

Stop going ahead until your 100% sure! I rebuilt the entire top end of a volvo because the mechanic was a retard and misdiagnosed a bad compressor head gasket!

Run a little hose from your pressure relief cap into a coke bottle filled with water (or put a pressure tester on the resevoir if you have one) and watch how much it bubbles when the engine is running. Then remove the air outlet from your compressor that goes to.your air drier and run the engine again, the compressor will be pumping air but with no back pressure, it won't go into the coolant. Check your bubbles/pressure now.....

Some block the air in line for the compressor to be safe, I prefer not to.