[boyt911sc]

Originally Posted by ossiblue

Here is the way the system works:

The line from the engine to the front cooler is always open through the thermostat. Contratry to what some believe, when the thermostat is closed, it blocks the return oil from flowing into the tank and opens the bypass. The bypass in the thermostat allows cold oil to bypass the path to the front (currently filled with cold, non-circulating oil), and return directly to the tank. When the stat heats up, the return line is opened and the bypass is closed, allowing the oil to circulate through the long path to the cooler and back to the tank.

That being said, if you don't run your engine, you will get a false reading on the stick as oil will tend to settle in the sump. If the engine was warm, running and the system pressurized, you will get an accurate reading even if the external cooler is not open as the loop is "full" of oil.

L.J.,

Well said. The explanation is clear and concise!!!! Many misunderstood how the auxiliary thermostat works. I wanted to add something to the discussion but it will be just redundantly unnecessary since you have covered the topic very well. This is the kind of information that makes this technical forum very valuable.

Tony