As per the answers from my last post

Coolant Blown Out of Reservoir (http://dieselplace.com/forum/forum_posts.asp?TID=7585&KW=ag4gt) http://dieselplace.com/forum/forum_posts.asp?TID=7585&KW=ag4gt

Let’s assume that the head gasket is leaking into the water jacket. How do I test for this condition? I need to do some testing before I take it into the dealership to have it fixed. The truck is under warranty and I do not want to take it in and have the dreaded “Could not duplicate” answer from them.

Thanks

You also were having temp problems.... low temp.

Get a test kit from Eastwood

Costs about $30. It sucks air out of the resevoir and mixes it with a blue liquid. If the liquid changes to clear or yellow.... you have combustion gasses in the cooling system.