I took the car for a quick spin (under 1.5 miles) and once I got down the road the temperature gauge started moving very high. Right before cutting the engine the needle suddenly jerked to the left, then straight up, and again to the right. My dashboard was otherwise behaving appropriately. Now I know my cooling capacity is reduced by having water and soap in the system, and a radiator with oil in it, but it still surprised me.
Could an air bubble cause this erratic gauge behavior?
In other news I think I have found the source of the oil leak! It's my headgasket that is leaking, oh joy.
The gasket is a 3-notch fiber which I can only assume is in desperate need of replacing -- aside from the external leak.
I'm wondering, could I just tighten up the head bolts in the mean time to try and squeeze the leak shut?
The draining and filling regime starts today and I hope to have it completed in two weeks or so. New radiators are in transit, too. Thanks for any advice.