I have a small amount of coolant leaking out from somewhere only when the engine is hot, it puddles on the ground for a few minutes after turning the car off. I can assume that it is leaking while driving and just evaporating but because the car is stopped I can see it on the ground. Its nothing more than about a 9" diameter puddle. I see the general area it is leaking on the right side of the car under the overflow reservoir tank. So far I have replaced the draincock, removed the reservoir tank and inspected for a crack or hole, removed and inspected the overflow tube from the radiator cap to the reservoir tank....all seem to be ok.

The reservoir tank is always empty and the radiator coolant level is noticeably lower every few days. Since I know I have a leak when hot please someone tell me that the block is not the problem!

Any ideas on the cause of the leak?

 

Check the upper hose and also check the condition of the connection between the overflow hose and the reservoir. On mine there is no clamp or anything, so if the hose got brittle maybe it's leaking out of that connection.

Is the car overheating at all?

 

It is not overheating at all. The hose is still very pliable and flexible, is not brittle or cracked. I was thinking about cutting off about 1/2" to get a tight fit on the plastic nipple of the reservoir tank since there is not a clamp to hold in on. The leak is definitely coming from somewhere on the lower end of all this. It is all dry up high.

 

I removed a few plastic covers/pieces to get a better look at the leak and have found that it does appear to be coming from the front of the radiator toward the bottom and will ONLY leak for about a minute once the engine is shut off. I drove it until the engine got good and hot then parked it with the engine still on and no leak. I then shut it off and viola it started leaking. I'm guessing a small hole in the radiator? but why only when the engine is first turned off?

 

The engine block is always hotter than the cooling water. That is just the physics of the thermal system. When the engine is running the water is moving and the thermostat keeps it at normal operating temperature. When you shut off the engine, the water stops circulating and that in the block gets hotter, approaching the block temperature. This causes a slow pressure spike in the whole system. The puke tank usually gets the results of the overpressure and that gets sucked back in when the water cools. In your case you probably have a small leak at the higher pressure of the spike but not at normal operating pressure. One thing you can count on is that it will get worse.