Review on Hayden Automotive 205 Thermostatic Sandwich by Steven Nina

It uses a small coil spring that folds when heated so the oil pushes on it too, sort of like a back door. The problem is that it is a bypass for cold oil flow and the hole is about 1/4 inch in diameter. When working with 5w30 synthetic and around 16 degrees outside temperature, it takes 3 minutes for the oil to reach the upper limit. Motor reports full pressure. I was wondering where the squeaking came from after fitting the top, which explains that. It actually allows the use of an oil cooler.