Coolant leaking from A/C drain line

I was hoping that someone can guide me in the right direction. I have a 02 Tundra with the 4.7 motor. I have a small amount of coolant leaking from the a/c drain nipple. I have bypassed the heater core thinking that the heater core was bad, but still dripping out the drain line. Any ideas how or why coolant is still coming out of drain after core was bypassed? Thanks

 

Sure it's coolant? AC system PAG oil can sometimes have a greenish color from the dye. Could have a leaking o-ring or something in the going on with the evaporator or expansion valve.

Hopefully that's not it and you just have some risidual coolant leaking out after bypassing the heater core.

Does the fluid feel watery or oily?

 

Damn. I fill my water bottle from that spout!

 

That's an interesting thought. It's oily and has a green tint to it. Water pump, timing belt, radiator, hoses were all replaced last fall. But with that said, I believe its coolant, because the radiator is low and I add some water to it every few days. Just until I can identify the leak. Doesn't leak that I know of when driving. After its parked, it's okay. After a few hours or overnight, there is a puddle under there.

 

If you don't have one, grab a cheap UV flashlight and see if the leaking fluid lights up like a christmas tree. That will tell you if it's pag oil or coolant.

 

Are you using green coolant instead of Toyota red?

 

There was green coolant in there prior to the new water pump/ timing belt/ radiator install. Currently just adding water as needed until leak is found. Found a possible spot this morning. Thermostat water neck o ring might be possibly leaking going through the valley and out the back of the motor. Working on it now

 

Got any signs of rust in the coolant? Usually when you mix the green with red, it kills the corrosion protection. I would flush it out with distilled water and then add the red myself which lasts twice as long as the green.

 

And the red is the proper coolant as prescribed by Toyota ?

 

That's my intention. I believe it is the bypass pipe o ring as I can see a little portion of the valley and it wet under there. Once o rings are replaced, I will flush and refill with correct coolant. Thanks

 

My brother has used "green" coolant in his Tundra for 20 years without an issue but that's a chance I don't wanna take . . . Toyota Red has a different formulation of chemicals etc. than the green.