MishimotoMMTS-CHV-01DL Low-Temperature Racing Thermostat Compatible With Chevrolet GMC 6.6L Duramax 2001-2016

These things are insane! Keeps my truck running about 180-185 on a 90 degree!

Worked perfectly, I was having issues with my truck not warming up to temperature during the cold weather. Threw these in and fixed my problem.Ps: when installing, you don’t have to unbolt the alternator , took me about 10min to install these

Installed in a 2015 gmc LML, truck heats up much faster, really noticed it when it started getting cold here in wisconsin. 10/10 recommend

Good product. Lowered operating temp from 210 to about 170 in my 05 Duramax. Worth the investment for an LLY known for its overheat problems.

I got these for my 2004.5 Duramax LLY. My thermostats were stuck open causing no heat. With the high prices of OEM thermostats I went this route with a suggestion of a friend. My truck still runs a bit cooler then I would like but I have nice warm heat now! I am sure this will help me out in the Summer though. Installation took me about 20 minutes in freezing new England temperatures. Make sure you pick up a little dexcool before starting install and after you put these in there is a bleeder valve ontop of the thermostat housing, open that when you fill the coolant bottle and close it when coolant starts to come out to insure no air in the system. I would of gave it 5 stars but I am not sure if I should of went with OEM temp or not.

All last winter I had a re-occurring check engine light for P0128 coolant temperature below thermostat regulating temperature on my 2005 GMC 3500. Upon removal of the factory thermostats I found one of them stuck open as I thought I would. Living in Las Vegas with 110+ ambient temperature days I'm always watching my coolant temperature, I find these cause the temperature fluctuate a bit more than the factory ones do, but they definitely made a difference by keeping the truck cooler. Exactly what I hoped for, cold enough to matter at running temperature and warm enough for heat in the winter and to avoid P0128 codes.

Easy install in my 2001 GMC LB7 dmax

Stuck closed after about 5,000 miles of use. Overheated 20 hrs away from home. Bought Autozone replacements to get us back. I’ve heard their radiators are junk, guess the t-stats are aswell

I installed this on my Duramax LBZ and found that the thermostats being to open at the same temperature as specified, checking with the reading on my Edge CTS2 and an infrared thermometer on the housing and inflow/outflow hoses. Seems to be of good quality and reliable so far.

my duramax runs 10 degrees cooler now which helps on hot days and pulling hills