Tim:

The heat in the engine compartment is normal. Every time I open that hood, I had to stand a couple of feet away, otherwise the heat is unbearable. Trust me, I have two Aerostars, and they are both the same. Herrington is absolutely right, the small hood opening acts a a chimney to divert all that hot air to our face (natural convection at work here, at last that heat transfer course is good for something ). As for the leak near the drain ****, next time you drain the radiator, open the drain **** completely, then you can pull it out. On it is a little O-ring. You can either replace that O-ring alone or replace the entire drain **** (I'm cheap, so I just did the O-ring). Both are available at Kragen.

Since the leak stopped, I would suggest you drive it as is for a while to see if it comes back. If it does, try to remove the upper intake manifold and tighten the lower intake manifold a little. Sometimes the leak is there instead of in the head gasket. If you want to check the head gaskets, open the radiator cap while the engine is COLD and run until it gets hot and the water is circulating. Watch for gas bubbles floating to the surface. If the bubbles are there, you have a head gasket leak. In that case, I suggest pulling both heads and have them resurfaced, put in new valve stem seals and torque them up. You have a 3.0L so you can reuse the head bolts, but only ONCE. Standard practice is to put a little paint on the top of the head bolts so the next guy who has to deal with the heads knows he has to replace them next time around.

Also, Dave is right, forget about the lower temperature thermostat. If your engine is cold, the computer won't kick in and you will be running in open loop, which is bad for gas mileage, and other things too

About the transmission, there are two things I would like to mention. First, don't use the crappy cork gasket that came with the filter. Go to bulkpart.com and order the paper gasket instead. The cork gaskets always leak on me after a few thousand miles, and there is no way I could make them leak proof. Perhaps others have found ways to do so, but I gave up. Second, next time you open up the transmission oil pan, drill a hole at the lowest point (about 1/2" in diameter), put a 10mm nut on it (on the outside) and take it to a muffler shop. They would charge you about $5 to BRAZE (not weld) it onto the oil pan. Then buy some copper washer (to seal) and put a 10mm bolt on it. Voila, you now have ways to drain the transmission without opening the pan. I find that changing the fluid every 6000 miles, even if it's only a few quarts, cannot be bad for your transmission. I change the filter only every 20,000 miles. As for completely flushing the transmission, put in a new filter, then do the drain-fill-drive sequence for 5-6 times and you should be done. At one time I concocted a gadget to flush transmissions, and it worked well, but too troublesome, with closing this valve, open that valve etc... you get the idea! After using it three time (my brother's car, my wife's car and my car), I now put it on top of the garage and never used it again. If any of you want it, I'll send it to you guys for free

Good luck with your new van