I recently had my coolant system flushed and filled, but now I have a leak “near” the drain plug of the radiator. I have a 90 GS with 167,000 miles and the original radiator. So after about 30 minutes of running with the a/c on, the temp gauge will start moving from the left side of the icon on the temp gauge to the right side of the icon before I turn off my a/c which allows the temp gauge to move back to the left. I have also noticed small puddles on the ground in that vicinity.
To the best of my knowledge the leak is not coming from the drain plug itself which sets on the vertical side of the radiator, but on the little nipple near it on the lower horizontal side. It is just dripping very, very slowly there.
What can I do? I’d rather not replace the radiator if I can just patch it up or fix it with a new drain plug? Is this some kind of pressure relief valve or something? Could this have been caused by the mechanic who flushed and filled my coolant or is this just coincidence that my radiator decided to leak when he did that?