Coolant Leak near Drain Plug


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?


Unless the leak is coming from a hose, it really sounds like your radiator is shot. Life expectancy on the radiator is about 10-11 years. You could try to patch the leak on the radiator, but it makes more sense just to replace it. If you want to do this as inexpensively as possible, buy a unit on Ebay from “Radiator Doctor.” It will be made in China or Taiwan, but the quality is very good and comes with lifetime warranty. Just my $.02.

As for patching the radiator…I havent havent had success with that since the cores on the top and bottom are made of plastic. My integra developed a small, hairline crack right where the hot coolant splashes againsts the core, coming out of the upper rad. hose. Patched it but it only worked for like a couple hours. Maybe since yours is at the bottom and the coolant isn’t as hot, a patch might work.