Looks like I need to do this project now. My H3 threw a code a few weeks ago and shop said it was the T stat. Code was reset and today it came back on. Gonna order the part and get after it.

 

This job was a pain in the butt. That stupid hose clamp was a beast (didn't have the right hose tool). Once I got that loose the rest was cake. Thanks all for the help.

 

Hello,
i need a new thermostat for my 2006 H3. My CEL is on and the codereader says P 0128. I checked the fluidlevel and i think the thermostat will not close properly. In germany Hummer parts are very expensive and i think GM put this thermostat in several trucks.

Can somebody give me the diameter and opening temperatur of the thermostat, so i can search for these parts in germany?

I want to change only the thermostat, because there should be no need to change the whole housing.

Thank you,
Jens

 

Just changed my therm and sensor, sensor is on pass side back of engine near firewall, therm is driverside under alternator, gotta pull the wheel and wheel well to get at it, took some time, but can be done....cost appx $90 for all sensor, therm, coolant, and new clips for wheel well. Ask if need answer to any above...

 

It's not easy, for sure but can be done, good luck....

 

Rick, this thread is over 2 years old. Check the dates before posting

 

[What easy way to remove the thermostat which on the right side of the engine, it's 2006 hummed h3.

 

Just finished replacing the thermostat on my '06 H3. Thanks for the helpful tips!
I will say, removing and replacing the upper housing bolt was one of the hardest things I've ever done. There is virtually no room to get to it. I used a small but bright LED light under the front side of the hose - that was the only angle to get any good light on it. After numerous attempts, my best angle was with a 6" extension on my 1/2" ratchet. I had to angle the ratchet up and over the other tubing to get to this rascal. I used some very sticky putty to hod the bolt in the socket to get it started.
Also, pay attention to the position of the hose clamp...on my first attempt, the position blocked the bottom housing bolt.
Good luck!!

 

@ 75K on my H3 starting to get these P0128 codes. After reading this thread with the degree of difficulty replacing thermostat. Going to delay till codes will not clear B4 changing.