I am new to hybrids. My 2010 Prius has a check engine light on. It banged and shook when I started it. I let it idle in maintenance mode for 15 or 20 minutes. Outside temp was 61. The fan never came on and I am wondering if the fan switch/motor is faulty. I don't want to warp the head. Also, what are the signs of a bad water pump? There is no temp gauge and I do not have the proper OBD2 scanner to read the temp. With no radiator cap, it cannot boil over.
A lot is easier with a usable scan tool. Watching the coolant temperature is the easiest way to see if the fans really don't start when they should (95℃) or if you're just being a worrywart. Of course you can tell if the fans are running by looking. With the water pump, it is easier to use the scan tool and watch its RPM. The boiling temperature is lower with the cap off than with the cap on. If the coolant reaches that temperature, watch what happens....
Shaking and cutting up at start is water in cylinder in this model fan should not come on for a long time at 61 degrees F. Take plugs out insert bores ope on cyl 1 and 2 at least . See the droplets on backside or right thrust side. That's the shake . Undo jug cap leave it loose maybe notice no or less shake. Because pressure isn't pushing water to head gasket creating what ya saw on borescope. Good luck
