I presume you are refering to the oil temp found on the
dashboard of most cars. Under normal conditions, the needle is
usually at the middle or slightly under. But if the needle has
suddenly gone up, its better to pull to the side and call for
assistance as your car is overheating. Do not attempt to remove the
oil cap - its gonna be very hot, turn the car off and call for
assistance. I have an oil temp gauge in my car and the oil temp has
gone up to 120deg before whilst the dashboard oil temp is still
showing normal operating temp. So if the needle has gone up, its
actually extremely hot and the car needs urgent attn.