Losing coolant DuramaxLLY
 

My 2005 lly has 250g on it and I'm losing coolant but can't find a leak I had a problem with an injector and replaced the seals and it's running but I'm still losing coolant. Any ideas?

you may have to look from underneath, look at the water pump this is usually the problem. if there is no sign of water leak at water pump, clean the cap on the over flow tank. also see if the top rad hose is hard after the truck sits overnight, hard hose is a good sign of a head gasket leak.

Is the coolant supposed to be in the injector sleeve? If not how do you seal it?