'99 Astro Coolant Leak
 

I have been chasing coolant leaks on this van, each time fixing one I find another. The latest appears to be coming from the area on the front of the engine were the oil pan, timing cover and block meet. It's not a massive leak, only enough to wet a 4-6" diameter circle on the driveway overnight. Any thoughts? I'm not sure what coolant passages are in this area, or why it would appear to leak here. Previous repairs include: thermostat housing gasket, all heater and radiator hoses and most recently the water pump.