I had a similar problem recently with my coolant reservoir. Started leaking for no known reason. When I removed the reservoir, I found that the bottom had been patched with fiberglass matte and epoxy. I peeled it off to find a nice, oval, melted hole....any guess? Yeah, heat. Lots of heat. From the infamous welder-non mechanic that repaired my passenger strut tower. I replaced it with an after market reservoir. .cheers KEV
