131-131 (97241130) Engine Coolant Thermostat with Gasket

Works, functioned, and fit like o.e. because that's what it is.

Identical replacement to the one that came out of my 2002 Chevy 2500HD Duramax. My original thermostat got stuck open, so it would take 30+ minutes for engine temp to get up over 165 degf, which is too cold for this engine to run. Once swapped out with this one ( and also swapped out the other thermostat - there are two thermostats side by side under the same housing in this engine, one opens at 182 and the other 185 degf), engine got up to temperature like it should in 10 minutes or so. Changing this was fairly easy. I drained the coolant by removing lower radiator hose (there is a drain Petcock on the bottom of the radiator, bit after breaking a few of these on other vehicles, I always just pull the lower radiator hose). Pulled intake resonance chamber, alternator positive cable, and unplugged a few wiring connections. After that, was able to pull thermostat housing, scrape clean with razor blade, and out back together. You don't need any gasket on the thermostat housing - rubber thermostat gasket supplied with parts is all you need. Refill coolant 50/50 dexron and distilled water then bled air out of engine block (there is an air bleed bolt on top of the thermostat housing you can use to do this). After air bled, started engine, let warm up until thermostats opened ( can feel upper radiator hose get warm). Once thermostats open, it will suck down about held the coolant reservoir, so make sure it's full. All in all, easy job. Took about 4 hrs. Fixed the issue.

Purchased as a 2 piece set for my Duramax. My originals lasted 191k miles so wanted OEM parts. Very happy with the item received and great price.

Good Delco OEM part in white and blue Delco box.

This was for my 2012 Duramax Diesel and is the rear thermostat in the thermostat housing. This is a 180 deg stat and the front one was 185 deg. I was unaware I had a problem until the truck set a code for low engine temperature. When you change this thermostat you need to change them both. This product came in a unmarked box with GM numbers on the top. It fit and looks like the OEM and so far is working fine.

Works

I read enough bad reviews of the off brand thermostats that I decided to stick with GM original equipment. Pay attention to the orientation when installing. Very easy job to do yourself and save some money. Temperature stability has been perfect since I changed both thermostats.

I always trust Genuine GM

Awesome

The part is as good as OEM

and also twice cheaper then local dealer parts store. Took about 1 hour to replace it. You also need about 1 gallon of dex cool to top it

Excellent product

Worked fine. Outer box was Delco, inner box plain white. Made in Japan