I have a 99 Durango with the 5.9 in it. I think i have a blown head gasket but am not sure. The exhaust smells real rich sometimes, I recently looked under the radiator cap and seen a milky swirl on top?? heard somewhere that that means a blown head gasket. I also noticed one day some smoke coming from under the hood but couldn't tell if it was coming from the valve cover or the head gasket. Also when i am driving when I press on the gas pedal it downshifts one gear but is real doggy like something is holding it back, but if i put it to the floor it downshifts again and accelerates fine. I want to be certain its a gasket before I start tearing into it. what is your input on the gasket repair stuff you put in your coolant.

 

get the cylinders pressure tested, and ask for a leak down test on each cylinder, if one of them fails either test that is the bank thats bad

 

DO NOT PUT ANY TYPE of so called fix it stuff in the radiator for headgaskets.. it will make a complete and utter mess and will do you more harm than good . and i 2nd that on getting a compression test done on the cylinders.. but most of the time not always but most you will have a miss if its a blown headgasket.( thats just in my experiences)

 

+ 1000 on that!