Leaks severely even with Teflon thread sealant. The bypass function does not provide sufficient cold bypass. Just bad apart from the price. The threads inside left a lot of burrs and pieces of metal that break easily and damage the engine. No alignment of spring center inside. The valve plate has no relief spring and can therefore damage the thermostat if it is overstretched. Also, 160F is printed on the thermostat. Is it 160 degrees Fahrenheit? My engine ran cold and I can see that too. It got stuck a few times and caused a high fever.