Review on ACDelco GM 131-151 Engine Coolant Thermostat - Original Equipment for Enhanced Performance by Stephen Lunn

No problem, fits perfectly and works great! If I can't get genuine GM parts, Delco/Delphi air conditioners are the only replacement parts I will use and they last much longer than the others. I've used cheaper parts, there's room for them, especially if you're in a tight spot, but generally they never last as long as genuine GM/AC Delco/Delphi parts. These are undeniably high quality parts that are worth every penny. I wouldn't recommend anything else for a GM vehicle. This thermostat has had a few cycles already and the temperature stays steady around 208°F and the temperature fluctuations are minimal but nothing out of the ordinary.