1997 Lumina Coolant Leak.

I have a 1997 Lumina that leaks coolant from the backside of the Engine. The leak is down lower, so far I havent been able to see exactly where its coming from. Its a 3.1 Liter. It doesn't overheat and there isn't any sign of water in the oil and its not the heater core, no steam inside the car. I had to replace the gaskets 3 years ago. In one of the threads someone had mentioned a "pipe" running across the back of the engine. I have to add about a half a gallon a week. Does that sound like I need another gasket change?

I took a closer look and the leak is out of a short tube with a downward 90 degree bend in the middle of the firewall. I can't see that is connected to anything.

I took a closer look and the leak is out of a short tube with a downward 90 degree bend in the middle of the firewall. I can't see that is connected to anything.
That pipe is to drain water that collects when you run the AC, so if antifreze is coming out of it, you have a leaking heater core. Smell any sweet smell inside car wehn the heat is on? or woindows that wont defrost seems greasey?

That pipe is to drain water that collects when you run the AC, so if antifreze is coming out of it, you have a leaking heater core. Smell any sweet smell inside car wehn the heat is on? or woindows that wont defrost seems greasey?

John;
Yes I can smell antifreeze, but my windows don't fog up when I run the defroster in the morning. That is why I was guessing it wasn't a heater core.
At least it doesn't appear to be a Gasket problem. Do you know if the heat is controlled by controlling water flow? So that I could just turn off the flow of water?

Unfortunately no, the heater core is part of the cooling system. Coolant is always flowing through the core. Quite possibly the connections at the core are worn out, or the core itself is leaking. At half a gallon a week, you probably won't see the windows fog up. The defog mechanism runs the AC, basically, to remove moisture from the air.

The core isn't too awfully hard on these models to replace. Just patience and some shop towels.