sgull

Have a bad coolant leak occuring with my 92 Accord. Not sure whether it's because of a leaking water pump or from a leaking o ring on the water pump end of the water pump inlet pipe which is connected from the thermostat housing to the water pump. Upon inspection from underneath, the coolant seems to leak from above the water pump weep hole from between the lower timing cover and the engine. With the car parked and the engine running there seems to be little if any noticeable leaking until the radiator cap is loosened, whereupon heavy leaking immediately occurs from the area I mentioned. Put the radiator cap back on tight, and the leaking pretty much stops. Assuming it might be the water pump leaking, I did take the upper timing cover off and started the car to see if maybe water might spray out from there, but it didn't. I can fill the cooling system up with coolant and like I said there's no visible leaking occuring until I take release pressure by doing something like loosen the radiator cap, then it leaks badly out of the area I mentioned. Also, it must leak out pretty bad when driving, as if I fill the cooling system then drive to work one day or whatever then check it later it's really low or close to empty again. I really don't want to go to the trouble to change the water pump if the water pump isn't the problem, because that entails having to remove the timing belt. I was wondering about the possibility it is the o ring on the inlet pipe on the water pump end that might be bad and could the source of this leaking. Here's a diagram which shows the o ring I'm talking about, part number 19 in the diagram: http://www.hondaautomotiveparts.com/...ry5=WATER+PUMP
I removed the inlet pipe and inspected the o ring but it does not necessarily look bad to the naked eye, not obviously deterioated or cracked or torn. The o ring on the other end of the pipe, which is identical but which fits into the thermostat housing, looks slighty nicer, but actually not much different. On removal and close inspection of the o ring on the water pump end of the inlet pipe, its really hard to say for sure whether it might be have some wear or imperfection that is allowing the leakage I described.
This particular o ring is not one available at local auto parts stores, but instead really is a Honda part which I would need to acquire from Honda. I can get one and see if it helps, but before doing that I'd like to get some opinions on whether from what I describe it seems reasonable the o ring is the cause, or if in fact it seems likely this is indeed the water pump leaking.