I have a '99 Deville that has recently been losing coolant. When I look underneath, the left side under the water pump is wet but the right side is wet from front to rear. Is there a way that I could pinpoint the source? It's hard to rinse it down with water in the cold temps, mabye I could bring it to a car wash and ckeck it before driving away. Also the last time that I filled the resevoir there was some foam with small bubbles in it and muck all over the cap that had never been there before.