2000 Honda LX, 120K, original owner, synthetic motor oil, all maintenance up to date. Oil/filter change, about 4 weeks ago. Added some coolant to the overflow tank when I changed the oil.

My wife reports that the air con was intermittent in 97 degree weather, then she got a check engine light, then a stall.

Opening the hood, there was some yellow gunk on top of the radiator passenger side, about a quarter cup, and there was a burnt insulation smell. A friend came and saw no oil on the dipstick.

I'm guessing a radiator issue, but possibly a blown head gasket. Any thoughts. The car was towed to our mechanic, but won't know anything until Monday.

Any thoughts?