c15 acert pushing coolant out radiator

Remove the compressor discharge line and run the engine until hot. If it pushes coolant still, head gasket(sorry). If it doesn't, air compressor.

 

You can have a bad head gasket, with no water in the oil. Mine was doing what yours is doing, and I wound up majoring it since they had the head off already. Had almost 1 million on it though.

 

usually if a head gasket is blown you have to check the liner protrution if it is below specs you have to pull the liners and do a counterbore cut. .004 to .006 is ideal. also if it blew on the head side of gasket you may have to redeck the head. if on the spacerplate side of headgasket, a new spacer plate. if the block doesn't have any wear you can possibly get away with the thinner spacerplate that cat has to get the liner protrution up to spec. ashop doing it may be around $4000 to $5000 doing it yourself half that. if you have a lot of miles on it a over haul may be your best option.

 

If you suspect pressure in the cooling system. First test the radiator cap with a radiator pressure test kit. They can test the cap and also help in checking for pressure in the cooling system as well for leaks. Install the tester on the radiator and run the engine check to see if it builds up pressure that is greater than what the cap is set for. If that initially shows nothing then rev the engine up to top RPM for a second or two then let it fall to idle. Do this several times and if it has a bad head gasket it will build up pressure over the limit the cap is set for. Most cooling systems will; run about 4-6 LBS of pressure.

There are some outside sources of pressure that can get into the cooling system such as a air operated fan sensor that sits in the cylinder head. A air operated heat control valve as well or even a air compressor. This is rare.

 

Cracked liner is also possible. Like John said do the bottle test. You can bypass your compressor, and with the truck engine off but ignition power on turn your interior temp selector back and forth while listening to the valve along the fire wall to determine that it;s an electric selector to eliminate that.

If the bottle test is still showing pressure after the engine is up to temp and the fan has cycled a couple times you know it's internal. Head - head gasket - liner ..

 

i have a cat 3406e and it was doing the same thing. I would notice drag at starting every Monday after it would sit for the weekend. This never happened on a daily basis. Eventually, I let it sit four days and it attempted to start by would only drag. Turns out water was sitting on top of a piston because of a cracked liner. The drag was because the water would not dissipate or move out and the piston could not move. I think they call this hydro locked. The mechanic at cat told me that it was a blessing that the engine didn't turn over at all because this would surely have bent a rod. Anyway, I could never tell any water in oil and no milky residue around filler area, but I have a quick release valve on my oil pan and when I opened it the water and oil came out in two separate streams. Looking at the dip stick showed no milky residue and no water was evident, so you may have to find a way to get some oil out of the pan in order to tell. Don't check it while its hot because the water and oil may be temporarily mixed, but check it after it has been sitting perhaps overnight and that will give you a better idea. I had no miss, no smoke, no hesitation, no overheating, no noisy engine, but the liner was done.