Occasionally it doesn’t idle when turning on, it’s really rough then turns off

I don’t know about the check engine light but there will be no throttle response. The check engine light should provide a direction to look in though. There are a many different reasons for no throttle response or low power. Low high pressure oil pressure, low fuel pressure, turbos gummed up, sensors clogged with soot, clogged dpf filter, throttle pedal fault, it’s pretty hard to guess what the problem is without a scan tool or the fault codes. I’ve googled the fault codes and sometimes you can find a just answer or a forum site that had the same problem and get the likely repair for it, or test procedure.

I believe it does that to build or regulate heat while regenerating the exhaust filter.

@@JasonTheMunicipalMechanic thanks🙏

This truck is a 2012

It should if it has a maxxforce dt engine

@@JasonTheMunicipalMechanic Yes MaxxForce. Same location?

Should be the same.

@@JasonTheMunicipalMechanic Awesome. Thanks!!!

If your losing coolant I would check the egr cooler for a leak.

@@JasonTheMunicipalMechanic i delete egr, when truck start coolant get all the way till low coolant lights come on, when i turn off engine coolant is coming back all tha way up till coolant overflow

If the level is changing like that I would say there is a air pocket in there. The loosing coolant is creating a pocket somewhere. I don’t know if you have a air compressor cooled from the antifreeze but if you do I would check your air tanks for coolant. I would lean more towards a head gasket, the head, or a liner. Have you tried pressure testing the cooling system. You can take the oil pan off, pressurize it and look for coolant dripping down from a cylinder. A coworker had pretty much the same coolant fluctuations on a duramax and it was a head gasket. He would drive it and the coolant would drop and when he opened the cap it shot back up. There are some other areas the coolant could be going but to have it drop about a gallon and rise again would have to be a pretty big area the def doser valve is an area coolant runs too. I would pressure test the cooling system to at minimum locate the coolant leak and I think it will probably be your rough idle too.

@@JasonTheMunicipalMechanic what are you recomend me to do my last question? to change air compresor or something else

I wouldn’t change the air compressor unless you know it’s bad. I think your problem is going to be the head, head gasket, or liner. I would take the oil pan off pressure test the cooling system and look for leaking coolant to confirm if taking the head off is necessary. Trying to rule out things I think a cracked compressor would most likely pressurize the cooling system, but coolant does run through it so it could be a suspect but unlikely. My first step would be pressure test the system and see if the pressure drops if it does I would look for external leaks. If I didn’t find any I would take the oil pan off and look for coolant leaking around the pistons. But the first step is finding the coolant leak and with a rough idle I’d say it’s getting into the cylinders. Parts are really expensive so I’d test for the problem before throwing parts at it.