Round machined hole in water pump housing leaking coolant

That little hole is called a tel-tale hole, it let's you know when the seal has started to leak, and prevents leaking coolant from entering the bearing..

You will need to replace your coolant pump..

look for a leak from the drain hole under the pump housing, if no leak not a water pump
take the car to a radiator specialist shop and have a coolant pressure test done to determine where the leak is
if it has plastic tanks for the radiator , they split with time and leak under pressure and a pressure test will reveal exactly where the leak is unlike a guess

THIS IS A WEEP HOLE IF YOU ARE LEAKING COOLANT THERE REPLACE THE WATER PUMP.

Hi, if you have water from the pulley area, it may be coolant leaking from the vent hole, in the water pump. This would leak more when cold, than hot. The repair, would be a water pump replacement. This is a fairly easy job, the only possible obstacle, is the fan needs a special holding tool, to dissasemble it. Otherwise, removing the upper radiator shroud, belt, and hoses, there are 4 bolts holding the pump to the engine.It is imparative that the engine block is clean , (to the metal), before the new pump goes on, then a mix of 50/50 dexcool, and distilled water, to refill the cooling system. Good luck...Coop

water pump failure, water pump on these run off the timing chain and the timing chain runs in oil, so they could not just put a weep hole on the pump because it would go strait to the oil pan, instead they redirected the coolant from the leaking pump to just below the thermostat housing. And good luck, it's at least a 6 hour job on these. Brandon-MO

If you can narrow down where the leak is coming from, it will be easier for you to fix, but it is most likely either a minor radiator leak, or your water pump. You can put a can of radiator stop leak in your vehicle, such as bars leak. It wont hurt anything. If the leak continues, and appears to be coming from the engine area, the water pump is failing, but also check around the thermostat housing, near where the upper radiator hose connects to the engine

Most likely the water pump seep hole, if it was running outthe crank It would not run, however it could be the upper radiator hose or the small bypass hose or the thermsotat housing.

The coolant is more than likely leaking from the water pump "weep" hole. If you were to remove the water pump pulley you would be able to see the coolant track and weep hole.
The leak is an indicator that the seal and/or bearing is wearing out and the water pump needs to be replaced.
If you have some common tools, time and patience, you would be able to change the pump your self. It requires draining the cooling system, removing accessory brackets and hardware then removing and replacing the water pump.
Good luck, let me know.
Regards,

when installing new o-ring on tube, lubricate o-ring and stick it in water pump. Then pull pressure back on tube and then tighten hold down clamp. problem solved

Sounds like either the water pump or the thermostat housing. The water pump has a small hole in the bottom where the shaft comes through, when the water pump gets worn it will leak here so you know to replace the pump. The thermostat housing will be at the motor end of the upper radiator hose where it attaches to the motor. Hope this helps.