signs of a leaking heater core

[snake109]

i fear i may have a leaking heater core . when i put the heat on to the floor vents just a little bit of heat comes out of the defrost vents which is just a leaking blend door i imagine, but it fogs up the windshield like crazy. the air doesnt smell like coolant and coolant doesnt leak on the floor anywhere. but i checked my coolant level and it is considerably low. apart from the foggy windows what else is there to indicate a leaking heater core? without having to pull the dash apart.

 

[Ponycar]

sounds like you answered your own question. I had the same window fogging problem...guess it leaked just enough to burn off and fog the windows. even though it may not smell, I bet the air feels 'wet'...one day my core puked on the floorboards

 

[Dan P.]

Take a look at the firewall where the ac condensation drips for coolant leaking out. It is located right below the heater core inlet and outlet tubes.

 

[stykthyn]

doesnt sound like it is leaking. may have deposits blocking part of the core. I would also check your thermostat. if it is stuck, your car wont heat up to temp properly and your heat wont work.

 

[bditty50]

When my heater core was bad it didn't give heat of course and also it leaked on the carpet. That's not always the case though sometimes it might be leaking at the firewall on the inlet/outlet tubes where the welds are. Sometimes if they are blocked inside you can do a coolant flush and cure it for a bit. Most likely though if you do a flush and there are calcium deposits it might start leaking then. Either way if it is the original heater core on your car I would replace it. I think on a 4cyl you can just open up the trap door behind the glovebox.

 

[Dan P.]

There is not a trap door, you have to pull the whole dash in order to get to the box.

 

[Ponycar]

I managed not to remove the entire dash, I got it pulled away just enough to expose the heater box. I cut the top of it out with a Dremel and removed the core. replaced it and taped over the cuts with alum duct tape. According to the manuals I have it calls for removal of the box, which means taking apart the A/C as well since the evap is under the heater core. either way it's a pain

 

[killercomet]

Yeah you can do some cutting if you want and save some time. A friend of mine just had his replaced on his SVO by an auth. ford tech. (his cusin) it took him 12hrs and I beleive thats the time it calls for.