Something alarming... maybe

Just loop the two hoses where they connect at the firewall

Mustang5L5 said:

I think auto parts stores actually sell a kit for heater core bypass.

Its just a tube connector and two hose clamps. Remove the two coolant hoses, and join them together. Then you can get to the core whenever you feel without risk of losing coolant in the interior.

Click to expand...

This ^^ is true. I had to do this a few years ago on my 89 when it's heater core went bad. The part you are looking for is generally with the hose clamps, etc.

Really? None of you think this could be normal condensation dripping off the evap core for the air conditioning, huh? Huh.

Doesnt matter if you have no ac, the heater core is still going out... or appears to be. It all runs through the same box

It seems a little heat/AC 101 is in order here.

The heater core and the ac evaporator core are both located in the black plastic box under the dash.

The hose you see sticking out from the firewall is not supposed to be connected to anything, it's simply a drain tube coming from the heater box that allows normal condensation that forms on the evaporator when running the ac to drain out onto the ground.

Even if you don't have the dash controls set to ac there can still be condensation because the ac is designed to cycle on and off when you have the control set to defrost.

If the heater core is leaking, the fluid will not be water coming out of the drain tube, it will be coolant.

Even if you don't have the dash controls set for heat, there is still coolant flowing through the heater core at all times while the engine is running... so not running your heat will NOT keep the heater core from leaking.

If it's determined the heater core is leaking and you chose to bypass it until it can be replaced, the correct way to do it to disconnect both heater hoses at the firewall pipes and use a short plastic or metal pipe to connect the two ends together so the coolant path is not obstructed.

Be aware when removing the heater hoses for any reason that there is a small metal restictor that looks like a bushing installed in the inlet hose. Don't lose this and always reinstall it when replacing the heater hoses. This restictor does NOT reduce the pressure of the coolant entering the heater core like many people think, it simply slows the movement of the coolant through the heater core so there is time for heat exchange from the coolant to the air passing over the fins of the core.

For those of you who plan on trying to tell me I'm wrong about the restictor and that it does indeed reduce the pressure to the heater core, picture this in your mind. Take a metal coffee can, cut a round piece of sheet steel with the same inside diameter of the can and place it half way down in the can. Drill a 1/8" hole in the center of that piece of steel and seal the edge where it meets the wall of the can. Now seal the top of the can with another round piece of sheet steel and drill a hole and put a fitting with a gauge and a nipple to fill with compressed air. Then drill a hole at the bottom of the can and install another gauge. Now pump the can full of compressed air from the top until the gauge reads 10psi... now look at the gauge mounted at the bottom of the can. It WILL read 10psi, meaning the hole in the plate that is dividing the can in half is not keeping both sides of the can from seeing 10psi. The pressure will be the same on both halves of the can... BUT, if air is flowing through the can, it's velocity will be much slower due to the hole in the plate dividing the two halves. This is all the restictor does in the heater system... that's why it called a restrictor and not a pressure reducer.

Hope all this information has helped you understand the heat/ac system... but in the end, you're going to have no choice but to eventually pull the dash and replace the heater core to fix your car properly.

Bypass? Well if you don't have A/C and you don't want heat, just take out the whole HVAC box. Saves some weight and clutter under there.

I took mine out, even though I have a perfectly good heater core and evaporator. I also removed the lines that run under the throttle body and to the EGR, looks real clean and eliminates other possible leaks. Saved some weight. I put it all in a pile and picked it up. Individual components weren't all that heavy, but put it all togeather and it has some bulk. I never use heat, even in the winter, I drive with the windows open in 15* weather. Yeah, I'm that badass. No really, my car isn't my daily. My pickup has ice cold A/C and heat that will burn you.

I wish I had a fridge that could chill a beer in minutes...I need a Nissan in my kitchen.

Yep, that's definitely coolant from the heater core. (it's green)

Bypass it for now, and later on you can remove the HVAC system behind the dash and remove the heater tube from the intake manifold. (if you really have no intentions of using the HVAC system in the future)

It does make the car much easier to work on. The only complaint I have from doing that to my cars is that sometimes the windshield fogs up. (use rain-x anti fog, and consider keeping a micro-fiber towel in the car)

I know I've said this before in other threads, but just FYI: keep any dogs and cats away from the coolant drip. Antifreeze is extremely toxic and animals drink it like it's cool-aid.