I have a 91 chevy truck and there is a small trail of antifreeze running along the outside of the inner fenderwell. It is coming from above and I can't tell exactly where it is coming from. The leak is lined up with the firewall but I don't see any antifreeze on the firewall. How can you tell if it is the heater core leaking? I don't see any inside the cab.

 

Bad heater hose, radiator hose, or leaky coolant reservoir.

Jim

 

Without seeing a pic, I'd recommend checking the back of the intake manifold also...

 

The intake is too far away from where this antifreeze is but it looks like it is coming out the drain hole for the ac maybe. Nothing is really wet where I can tell. I thought there might be some clues for the heater core.

 

Okie dokie...if it's coming out of the ac drain, it sounds like the heater core then. If you turn on your heat and steam comes out of the vents, then you've definitely narrowed it down to the heater core.