temp needle flickering to zero and back

hey guys. any thoughts,

temp needle never goes over half way mark but flickers from zero to half way, a lot, kinda all the time.

freaked that it was a coolant or oil prob. filled coolant reservoir when engine was cold a couple of times and had some coolant leaking out bottom of engine. the seal on lid of reservoir isn't sealing, is that it?

also the engine oil cap came off as it became threaded and sprayed oil over engine, luckily i checked it daily since coolant issue and bought new cap which is holding fine.

temp needle still flickering.

while I'm talking to the wise....

if i go over 60mph the front door open lights (on dash) flicker on and off, go over 70 and they stay on.

if i put on the awesome parking sensor the front right is always on full beep warning of immanent collision even when park on a beach, very alone.

I'm new to hiace life and loving it.

thanks for any pearls of wisdom.

dom

Re leak, was it from the engine itself? If not, check radiator drain plug, they can become brittle.

My temp gauge is usually somewhere between zero and halfway, usually around 1/4 but can change suddenly. May be a dirty temp sensor.

Werner