How to remove and replace your thermostats. This was done on my '02 LB7 after my Attitude monitor never would get above 145* under normal driving conditions. I soon found out why. Now she runs at 180*-187* with some play time thrown in and my mpg's has actually improved as well. This was my first time on a diesel so bear with me haha.
What you will need:
3" extension (I used a 6. It was easier)
1gal of coolant
About 25 minutes.
Step 1: Remove resonator (big black plastic thing that says duramax 6.6 on it)
Step 2: Locate thermostat housing. It's towards the front of the motor in the middle. Real easy to get to.
Step 3: Remove these bolts.
I ended up taking the back one and front bleeder off which in the end wasnt necessary.
Step 4: Remove 2 bolts holding radiator hose in place. The green circle is a hidden bolt on the other side under the plug-in wires.
Step 5: Lift the top of the housing out of the way so that you can change the thermostats out. PLEASE DONT GET THESE MIXED UP. As you can see, I just set mine up on the closest bolt.
Swap the stats out and do everything in the reverse order to put it back together. DO NOT OVERTIGHTEN BOLTS. Not sure what the torque specs are
but if its not leaking, its tight enough.
Fill to the proper level with coolant and let the motor idle to operating temp. Run it down the road and back if you want. Let it cool. If you have air in the system, unscrew the bleeder screw a little bit til fluid comes out and squeeze on the hose. Check the fluid again, add if necessary.
Sorry this is so shitty, but I've had the flu the past week and was running a temp when I was doing this. If you have any questions, feel free to ask someone else who can better answer them for you. Good day...