Got a nagging coolant leak - drips out a quarter cup or so but doesn't start dripping until hours after being run. Seems to be coming from very bottom of timing belt cover but removed that and found no trace of coolant in there. No signs around the water pump or thermostat housing either. Traces of coolant go up a little bit from the bottom of the timing belt cover but disappear. There are not nearby hoses to "spout" over to the location where it it looks like its coming from. I'm stumped.

So, I have compressor and a Schraeder valve so how do I pressurized the cooling system in order to find this leak? Is it done thru the coolant resovoir cap? Maybe by epoxying in the valve? Also, how do I make sure I don't overpressurized and blow out something?

thanks,