Back to the 97 Aerostar again.... It appears that the heater core is nearly plugged. Some heat gets through, but not much.

Heater valve & vacuum work fine. A friend said to pull the valve off and connect a garden hose to the outlet and hit it with some short blasts of from the garden hose. Then connect to the inlet and repeat until it flows free and clean.

But, and this is a big butt, I have done these kind of things before and been sorry later. So I thought I'd ask the online brain center for some (good) advice first. The last thing I want to do is open a leak in the core and hose down the front seat.