Fog in Interior Compartment from A/C

Hello Bill! Let start the troubleshooting: The A/C "engages" on defroster because the defroster "need" dry air and the A/C "dryes" the air but it works in conjuction with the heater core.(if you move the setting on hot) OK ... to start, Does the fog get stronger as the car warms up and when the thermostat its on "hot"?? Try running the blower with Max A/C and see if the fog is still there. If the fog seems to go away after the A/C has been running awhile, then the problem is probably the heater core. (has an small hole and the hot water as a vapor its blowed trought the ventilation) let me Know on your findings!

[quote="fisherman"] Well, I can tell you that the fog persists on Max A/C and Normal over an hour's ride and it does seem to get stronger the longer I ride. You might be right about the heater core. I have a problem with the engine light coming on, occasionally, as well even though the coolant and oil llevels are good. The radiator shows good circulation and I replaced the thermostat only recently. Could a heater core leak limit the effectiveness of the cooling system without a significant loss of coolant? I check under the car for leaks, but never see any and the coolant resevoir level iis pretty constant. I hope some of that information helps. Thanks again.

Hello Bill...

Well, sometimes when the heater core has an small "leak" and insignificant quantity of water its lose, due to the "pressure" of the cooling system..
Check on the passenger side floor for leaks, (even a drop )
also.. have you ever find out if your vehicle its equipped with a cabin filter?
if so look for it and check it...

I`m thinking... If the "fog" its coming from the engine? have you check for fog under the hood?

let me know on the leak under the pass. side..

I`ll keep thinking about it..

BTW your car its in really good shape!!

Its a beauty!!

[quote:362f01d5e6="fisherman"]Hello Bill...

Well, sometimes when the heater core has an small "leak" and insignificant quantity of water its lose, due to the "pressure" of the cooling system..
Check on the passenger side floor for leaks, (even a drop )
also.. have you ever find out if your vehicle its equipped with a cabin filter?
if so look for it and check it...

I`m thinking... If the "fog" its coming from the engine? have you check for fog under the hood?

let me know on the leak under the pass. side..

I`ll keep thinking about it..

BTW your car its in really good shape!!

Its a beauty!![/quote:362f01d5e6]

Hello Fisherman,

Thanks for the compliment on the old Ford. I got it from my boss when it was lwft to him by his elderly aunt who had passed away. It was sitting in the driveway for months and he wanted rid of it in a bad way. It looked pretty scary at the time, but the car started right up with a jump and he only wanted $100! I've put a few hundred into it and its a great little car. The interior's like new and it got really, very little use.

I followed your suggestions today and found that I don't have a cabin air filter. Also, there's no "fog" evident under the hood. I did find out that I was mistaken about the coolant loss, though. I was down almost 2 quarts, so there's definitely a leak somewhere. Thing is, I couldn't find it. I topped off the radiator with coolant and I checked the hose connections, the radiator, the water pump gasket, the radiator cap and petcock and finally, the passenger floor area under the heater core. Not a drop of anything, not even under the car and I had it running for about an hour, maybe a little longer.

I ran it for most of that time with the AC on, on Max and Normal and the engine light never came on, so that problem was, probably, just from the low coolant level. The "fog" problem and the coolant loss are recent occurances, so they must be related. Still, I didn't smell anti-freeze in the interior at all and the only moisture I could find at the heater core enclosure was condesate from the AC and it was just water, not anti-freeze.

I took the car for a ride, about 1/2 an hour and the "fog" is still there. I'm thinking of trying to take the casing off of the heater core, if I can do it without taking half the dash apart to try to get a visual of the heater core. Maybe the leak issmall enough to stay in the enclosure and not drip to the floor, or the enclosure is pretty well sealed after 24 years. Be able to see the heater core might settle the question.

In the meantime, if you have any suggestions, I'm all ears. Your heater core theory still makes sense, though, so I'm gonna try to take a look and see what I can see.

Thanks again, Fisherman and enjoy the weekend.

Bill