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Honda Accord 97 Weak A/C w/ Mist

As you can glean from Discussion Title, I have a 97 Honda Accord that has been weak in producing cold air with the a/c on since we bought it three years ago. The car has been the “third car” for kids to drive so not a big deal. Now that one of the “kids” is commuting this summer to an internship, the hot car is a problem. I drove the car this morning as I just drive to the train, and noticed mist coming out of the dashboard vents when the a/c was on. The mist stopped when the a/c was turned off.

Does this misting mean we have an evaporator core leak, or other problem? It certainly doesn’t seem like just a freon boost is needed.

If the evaporator core needs to be replaced, how bad a job is that? I replaced one in a '72 Plymouth Duster once and didn’t seem so bad.



You need to have the pressures and the system evaluated. It could be low pressure, high pressure, a partially clogged orifice tube, or any number of things. The misting could also be a clogged drain valve on the evaporator box. With a car this old, a dirty condensor coil could also cause problems you’re describing. Or a combination of some or all of this. Best to have it looked at by a professional or at least someone who knows A/C systems.

From my experience, the vapor from the vents is the first indication of low refrigerant level. If you continue to drive it like that, the evaporator can ice over, causing restricted airflow. Get it checked out by an A/C technician.

I too have a 97 Accord and it too can have a weak AC. The biggest problem with this car is the bad design for the heater control valve. The issue is that as the car ages, the cable that controls this valve and the blend door goes out of adjustment and cannot close the valve completely.

I discussed this with another Honda owner on this forum today.

Please look here for the complete explanation.

In the 97 Accord, this valve is hard to see and reach. You do not want to do this unless the engine is cold or you could get burned. Stand on the passenger side of the and look on the firewall area under the intake manifold about the center of the engine. You will see the 1" dia black hose with the valve in it and the cable going to it. Turn the arm on the valve ccw as far as it will go.

One more thing, your condensate drain is probably plugged up as well. water fills up in the evaporator chamber and spills over to the heater chamber where the hot heater coil causes evaporation.

Okay…popped the hood and found the valve described by Kieth. The valve control armiture position is in line with the refrigerant line, pointing away from the firewall. i could not rotate it CCW or CW. Started the car and turned on the A/C and the valve position did not change.

What would i do to verify valve operation? Is the valve in the correct position? Is the valve operated by vacuum or mechanically from inside the car?

Thank you,

Pinky (Tom)

I think you may just have a blend door problem, like keith said. Usually if you’re getting mist from your vents, it means the evaporator is getting nice n’ cold. But the cold may not be getting to you. The best A/C I’ve ever had on a car is on my old car. If you turned off the air, then turned it back on in a minute or so, you’d get instant fog from the vents with very frigid air–like when you open your freezer and see fog drifting out. It used to surprise my passengers. The mist you see could be pretty normal under certain operating conditions. An evaporator leak would likely be invisible and odorless, and I’m pretty sure you do not have this problem.

Sure, I would have the pressures checked, but have them check your blend door and controls too if the pressures check out.

I don’t know of what valve in the refrigerant line you are looking at, the heater control valve is in the rubber heater hose. See picture above. Have someone rotate the heater control on the dash and you should see this arm move. The cable attached to it moves it. Just finish closing it by hand.

see if this works

OK the second link works, that is the air cleaner tube in the upper left of the picture.