Hi, my blue temperature light goes off a couple minutes after starting. It can’t mean that the engine is fully heated because the heat is still cold. What exactly does the blue light going off signify? Is mine defective do you think?
Mine goes out between 106 and 108 degrees fahrenheit every time, although during the sub zero winter days it did take longer, about 112 degrees on those days. Im easy on the gas until about 160 and then I drive normally. Doesnt take long.
There is a nice video (using a heat camera) of a subaru turbo motor warming up. There was a big difference in warmup time for various engine components. The take home message for me is to wait several minutes AFTER the blue light turns off to get on the turbo. Probably not as important in NA and/or stock engines. I have noticed that in the winter my (modified) engine can knock if I get on the turbo right when the blue light turns off.
I have an older subaru. Compared to other car engines, their coolant passages are small and the engine doesn't hold much coolant. It is designed to heat up fast to improve emissions. In your later Subaru it is possible the thermostat warms the engine first before allowing coolant to go to the heater core.
My blue light always come off at 50C... Yes the air is still cold at that temp, your gauge is fine. A good heat start at about 80c, it takes a couple mins of drive after the blue light off.
Usually when the blue light is On you should wait before activating the heat because air will be cold and you will increase the engine warm up time (inefficient).
Also if I have the time to, I wait that my blue light goes off before driving the car. If I have no time I be very easy on the throttle until then.
Be careful, I've seen some post in here mentioning that when the light goes Off you can smash the Throttle, that is no true! 50c is way to low of a coolant to put engine at full load! 90c is the operating temp and will take couple mins of driving to get there. Your oil temp will take about 10-15 mins to get optimal (under normal driving warm weather, 25mins when extreme cold).