[timeless2]

My DD is perfect, but I have one little nitpicky thing I want to know about it. When I run the A/C and it’s on the “fresh air” setting, water vapor/steam comes from the vents on this setting, but not on the “recirculate” setting.

A bit on the car. 1998 Honda Civic EX. Clearly was a gravel road driven car prior to my picking it up.

My initial thought is that the condenser runoff line is either partially or fully plugged. Reasons for this supposition:
1. The vapor exists.
2. There are no cooling issues otherwise.
3. I noticed a substantial puddle of water below it in the driveway once, just as I backed up after unloading some passengers. This could have been the inertial spilling of pooled water in there somewhere.
4. Being a gravel car and its age make me wonder if dust could have accumulated to almost “cement up” the drain hose from the condenser.

Any other ideas before I crack down and get below it to see what might be the issue?

[Darkwriter77]

Hmmm ... when I first read about the vapor, my first guess was going to be the heater core, but then I read the rest.

I'd say your first guess with the drain tube being plugged would be a good place to start. Was the car parked under a tree where a bunch of leaves and such might have fallen into the cowl/vent area, as well?

It also might just be the design of the HVAC system, itself, in that it gets cold enough to cause some condensation in the ducting somewhere (especially since you live in the Midwest, as humid, muggy, n' sticky as it gets), even after air has gone through the drier, and it's just blowing that out. Not likely, but possible, I guess. I've had a couple of cars in the past do the same thing - not consistently, but every now and then, especially just before or after a storm or when it's just ungodly humid outside.

[svttech76]

on days where it is very muggy or where the temp is above 80 you should be using the recirculate mode or as it's labeled in a mustang ( MAX A/C)

The reason for this is in recirculate mode the A/C is recirculating the air and this interior air is less muggy and will create less condensation.. What is happening is the air is so humid that the condensation is building up and then is getting blown through the vents.

I am not sure if honda points this out in the owners manual, but ford has it in the owners manual to use max a/c on humid days or when it's over 80 degrees.

Plus you will get better mileage following this, using the outside air on hot days works the hell out of your a/c

[Darkwriter77]

I use Max A/C on the T-Bird or nothing at all. When it's 100+*, you gotta have COLD air, or you might as well just roll the windows down and suffer. Didn't know that 80+* was an official Ford recommendation for Max, though - I always just thought it was for people with allergy conditions or dusty climates. Interesting...

[timeless2]

Figured it out. It was 6 ounces low (capacity 21 ounces). With an insufficient amount of refrigerant in the system, I'm guessing the condenser was unable to remove all traces of humidity from the core before the fan pushed the air throughout the ventilation system.

I took it into the shop for the 90,000 service & the timing belt/water pump change and they were kind enough to top off (free of charge) the Civvy with Freon to keep my arse cool.

[Darkwriter77]

*in Cartman voice* Schweeeeeet!

Never would've thought of that as a possibility, but it does make sense.