Another thought would be to carefully inspect the liquid that is emanating from your exhaust. I have a 1995 Aerostar 3.0L V6 that I recently purchased. After getting the machine home, I noticed that it was dripping from the exhaust when first starting-up the engine (about 1 drop every 5-10 seconds for the first 10-15 minutes). The cooling system was dirty, and had been filled with H20 for months. I flushed the system (2 quarts of Prestone cooling system cleaner), and flushed the system using a Prestone garden hose flusher (cut hose atop alternator, and installed "T" adaptor), and the system was cleaned out effectively. I added a gallon of Prestone, filled with water, did the heater thing (on full and max flow), and topped this system off. So far, so good. However, the tail pipe still leaked. Didn't expect a fix by cleaning the system, but wanted to see if the tail pipe liquid "drip" was clear (water) or colored (Prestone color). Bad news: yellow/green drip. Knowing that I have either a cracked head or a partially blown head gasket, I added a bottle of Bars Leaks. Some improvement, but not perfect, but no leaks at all after 15 minutes at idle or use. Next plan is to flush system again, and follow strict procedure outlined in "H & W Block Sealer" instructions: flush, drain, add limited water, add product, run, then drain, and allow cooling system to "dry" for 24 hours (with all ports open: filler, draincock, and "Prestone flush port"). Frankly, I think it will work. We will see. One thing is for sure, there will be no removal of this engine for a replaced head gasket, or engine overhaul. Any other ideas?