Heater Core Question (I think?)

caine0

Member
Jul 13, 2003
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For the past couple of weeks there has been a tiny bit of smoke coming out of my vents. Nobody driving in my car has noticed it except for me because it is just a very small constant flow. It mostly only happens when I open my window and the air starts sucking it out. Then to test to see if it's the heater core I switched the fan to full, and put the other knob to "vent". A big puff of smoke came out of all the vents and kept on smoking for a bit. I thought maybe it's just because I hadn't used the heat for a few months, since it's been so hot outside. The heat is still blowing very hot from the vents.

My question is, would it be the heater core that has the problem even though it's still blowing very hot air? I have gotten the oil that people talk of on my window, had to wipe it off a couple of times now. Is there anything else that could cause this problem? I don't have very much spare time to work on the car, so I don't want to have to rip apart the dash to do the heater core if that's not the problem. Also, about how long would it take me to swap in the new heater core if I've never done this before? Thanks.
 
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caine0 said:
For the past couple of weeks there has been a tiny bit of smoke coming out of my vents. Nobody driving in my car has noticed it except for me because it is just a very small constant flow. It mostly only happens when I open my window and the air starts sucking it out. Then to test to see if it's the heater core I switched the fan to full, and put the other knob to "vent". A big puff of smoke came out of all the vents and kept on smoking for a bit. I thought maybe it's just because I hadn't used the heat for a few months, since it's been so hot outside. The heat is still blowing very hot from the vents.

My question is, would it be the heater core that has the problem even though it's still blowing very hot air? I have gotten the oil that people talk of on my window, had to wipe it off a couple of times now. Is there anything else that could cause this problem? I don't have very much spare time to work on the car, so I don't want to have to rip apart the dash to do the heater core if that's not the problem. Also, about how long would it take me to swap in the new heater core if I've never done this before? Thanks.

if you have oily residue on your windshield then yes your heater core is leaking. also you can check your carpet under the airbox for moisture. id recommend replacing it asap since a nasty spill in the cab of the car could be disasterous. hot water will always circulate thru it from the motor.

you have two options.

a) loop the water pump feed lines back into the water pump and delete the heater core. no more heater. (temp fix?)

b) remove the entire dash, center console, seats, steering column, etc etc which takes about an entire weekend to do and replace the core with a genuine ford replacement.
 
ka0tyk said:
if you have oily residue on your windshield then yes your heater core is leaking. also you can check your carpet under the airbox for moisture. id recommend replacing it asap since a nasty spill in the cab of the car could be disasterous. hot water will always circulate thru it from the motor.

you have two options.

a) loop the water pump feed lines back into the water pump and delete the heater core. no more heater. (temp fix?)

b) remove the entire dash, center console, seats, steering column, etc etc which takes about an entire weekend to do and replace the core with a genuine ford replacement.


the seats too? wow, I don't think I ever had to do that one...I've replaced my core four times (really high flow water pump=too much for stock heater core) and never even had to pull the dash...I just pulled the blower, the glove box and weaseled the box down far enough to pull the core from the hole where the glove box was...

however, if you still have working A/C, I still have yet to find a way to change the core without discharging it...
 
Definately sounds like a bad heater core, mine had the exact same symptoms... a little steam from the vents, condensation/oily film on the windows, but still blew hot air.

I ended up just bypassing the heater core with a U shaped piece of hose and a couple splices. The haze on the windows was getting so bad it would seriously impair my vision on rainy days.

txstang84, I assume you have an '84? I've heard replacing the core on the older cars is easier than it is on the '87-93's...