My '86 240 has about 180 K miles. I've owned it for four years and it has always leaked a small amount of coolant from under the intake manifold. It really looks like it is coming out of the head gasket. The car runs great and isn't getting antifreeze into the combustion chambers. Should I go ahead and replace the gasket? I was also thinking of having the head milled while it's off. While I have it apart I'll change the water pump, seals, timing belt, tensioner, and V belts. I also noticed on my last long trip in the summer that the car's temp gauge worked its way past the halfway mark when going up hills on the interstate. I have already repaired the circuit board in the cluster, so the gauge is giving an accurate reading. Maybe it's related to the gasket?

Thanks in advance.
Dave