This post is my attempt to describe the process of replacing a thermostat housing on a 2012 Jeep JK with a 3.6L V6 Pentastar engine. I am not a professional mechanic, I just try to do as much work on my jeep as possible. It helps me learn more about my vehicle and save some money that can be spent on parts and upgrades.
The primary function of a thermostat is to maintain a minimum operating temperature in your car’s engine. When you start your engine cold, the antifreeze / coolant mixture is kept within the engine by the thermostat. When the coolant temperature reaches the specified opening point of the thermostat, it opens. Coolant will then flow through the radiator to keep the engine at a temperature close to the rated temperature of the thermostat.
The reason I needed to replace my thermostat was because one morning while driving to work, the “check engine” light came on. When I got home I plugged in my Flashcalto read the code. It was a p0128 code (an indication of a faulty thermostat or ECT – engine coolant temp sensor). After talking to few people I decided that the first thing I’m going to replace is a thermostat and see if that fixes the problem.
I got the new thermostat housing and a gallon of coolant at my local dealership ($34.00 and $24.00 respectively).
VERY IMPORTANT: Make sure you get the correct type of coolant for your Jeep if you’re going to be adding it to your system. Read this post before proceeding any further!
Remember that if you drive a MY(model year) 2012 or older Jeep Wrangler you need a HOAT (Hybrid Organic Additive Technology) coolant, and if you drive a MY 2013 and newer Jeep Wrangler you need an OAT (Organic Additive Technology) coolant. These two types of coolants DO NOT MIX!