Hello guys im new to this site! A couple of weeks ago my check engine light came on and i checked the engine code and it came up P0128. I looked up the possible cause for that code and it stated it could be a bad Thermostat. My question is what would i need to replace that part? I know i need the part but what coolant should i purchase? I was attempting to purchase the part and what else i thought i needed so that my brother can help me change the part but there are so many options given and I really dont want to buy the wrong one and mess up my jeep. I know this might be a dumb question so sorry in advance and thank you.