A/C dripping from condensation?

[69hugger]

This is my first "hotrod" with A/C and I just got back from my first road trip, (about 4 hours each way). It was mid to high 80's and pretty humid.
The A/C worked great, except after an hour or so on the road it started to drip condensate from the outside of the floor vent and A/C housing onto the passenger floor and later dripped from under the dash onto my feet. The dripping was substantial. My wife had to cover her feet with a towel to keep them & the carpet dry. I was also worried about my stereo unit getting ruined, and this maybe even causing an electrical short.
The dripping doesn't occur when driving the 10 to 40 miles I normally drive the car. But I will almost always see vapor condense on the center dash vent.

On a scale of 1-10, this is a "3" of concern to me.

I called V-A & they said it is simply a function of the air temp differential, and is "normal". I have never experienced this in any other A/C'd car, although they weren't black cars with aftermarket air.

The normal condensation drain is not leaking inside the car and is working fine as best I can tell.

Have you experienced this? Ever heard of it?
Do you worry enough about it to fix it? Maybe insulate the ducts?

Any experience shared is appreciated.

Bill

[Revved]

I've got something similar happening with a vehicle in the shop right now with a Vintage Air System. Driving on surface streets with stop and go traffic there is no issue, but extended highway driving (45min+) it starts getting condensation dripping out of the evap case inside the vehicle. I've already verified the evaporator case drain is clear and I get normal condensation drip with normal driving. My guess at this point is that the evaporator is icing up and blocking the evaporator case drain. The car is apart right now for other work so I haven't been able to test my theory yet by playing with the blend and adding some heat into the case to see if it keep sit defrosted.

Try adding a little heat on your blend to see if it helps. These systems run a heater bypass valve to keep hot coolant out of the evaporator case when on full cold so the A/C blows colder...but it could be getting too cold.

If I remember my A/C theory propoperly an overcharged system could also cause an evaporator to ice up. Most of my experience before the pro-touring work was with fixed orifice tube systems rather than expansion valves as all of these aftermarket systems seem to be.

[69hugger]

Originally Posted by Revved

I've got something similar happening with a vehicle in the shop right now with a Vintage Air System. Driving on surface streets with stop and go traffic there is no issue, but extended highway driving (45min+) it starts getting condensation dripping out of the evap case inside the vehicle. I've already verified the evaporator case drain is clear and I get normal condensation drip with normal driving. My guess at this point is that the evaporator is icing up and blocking the evaporator case drain. The car is apart right now for other work so I haven't been able to test my theory yet by playing with the blend and adding some heat into the case to see if it keep sit defrosted.

Try adding a little heat on your blend to see if it helps. These systems run a heater bypass valve to keep hot coolant out of the evaporator case when on full cold so the A/C blows colder...but it could be getting too cold.

If I remember my A/C theory propoperly an overcharged system could also cause an evaporator to ice up. Most of my experience before the pro-touring work was with fixed orifice tube systems rather than expansion valves as all of these aftermarket systems seem to be.

Sean,
Mine was definitely freezing up last summer, as it would slowly drip from the drain for hours after I shut it off after driving with the A/C. But I opened the system last winter, and had it charged with the correct amount of 134 (1.4# if I remember) by a shop this spring. It shouldn't be freezing up, but who knows? I was thinking about it freezing, but didn't know how that would lead to the dripping. If anything, it should start blowing warmer as you lose airflow over the evaporator from the ice formation.
Funny you mention adding heat. I wondered about that too, so I questioned V/A about it. They said not to do so. It would not help, and would simply hinder the performance of the system.
It makes me a little less concerned than thinking mine is the only one doing this, but I am still not comfortable with water dripping on electrical stuff & stereo equipment.

Anyone else ever fixed this?

Bill

[ProTouring442]

The evaporator is likely not icing up, as that would restrict the airflow through the evaporator and cause warm air to blow out of the vents.

A couple things come to mind:

Ensure the drain is clear, and that it is at the lowest portion of the evaporator case.

If water is condensing on the outside of the ducts, try wrapping them with insulation.

Metal outlets will usually have condensation and dripping (this was common on cars "back in the day"). There isn't much that can be done about this.

One thing that can help is, once the temperature in the car is where you want it, leave the fan on a medium setting and increase the temperature setting.

Insulating the under dash area (including hush panels under the dash) can help reduce condensation.

[Vince@Meanstreets]

VTA gives you a little strip of tar like paper. I had to cover all the metal sections of the interior tubing. Mainly the high side. I've used Dynamat and home depot stick on foam insulation too.

Never had it come from the vents though.

[dhutton]

Did you seal all the vents and holes in the firewall? It sounds to me like you have a lot of outside air leaking into the car.

Don

[Rob Ruthless]

Originally Posted by 69hugger

This is my first "hotrod" with A/C and I just got back from my first road trip, (about 4 hours each way). It was mid to high 80's and pretty humid.
The A/C worked great, except after an hour or so on the road it started to drip condensate from the outside of the floor vent and A/C housing onto the passenger floor and later dripped from under the dash onto my feet. The dripping was substantial. My wife had to cover her feet with a towel to keep them & the carpet dry. I was also worried about my stereo unit getting ruined, and this maybe even causing an electrical short.
The dripping doesn't occur when driving the 10 to 40 miles I normally drive the car. But I will almost always see vapor condense on the center dash vent.

On a scale of 1-10, this is a "3" of concern to me.

I called V-A & they said it is simply a function of the air temp differential, and is "normal". I have never experienced this in any other A/C'd car, although they weren't black cars with aftermarket air.

The normal condensation drain is not leaking inside the car and is working fine as best I can tell.

Have you experienced this? Ever heard of it?
Do you worry enough about it to fix it? Maybe insulate the ducts?

Any experience shared is appreciated.

Bill

69hugger,
Sorry you are having issues with your a/c system. You should be concerned; condensation dripping inside your interior is NOT normal. There are 3 reasons why this may have happen to you.

1. There is a crack or a hole in your evaporator. Water always follows the path of least resistance.
2. The hose connection to your evaporator is loose or not connected properly.

If neither of these are the case then you can message me and I will tell you the only thing left it could be.

[GregWeld]

Gwen's Brizio built '33 Ford has a VA unit and was doing this exact same thing. On our first trip from San Francisco to LA - it was pouring water out from under the dash. Brizio found the unit to be holding water due to the case and faulty drip tube (the factory - not Brizio's installation) issue. They fixed this and the problem was solved.

Her car is a convertible - and we just drove the car from SF to Austin Texas.... with the A/C blowing the whole time... When it got really humid we had one or two drip from under the dash - but not the water that WAS coming from the unit as described above. I would say it was normal and only happened once. I then turned the temp knob down just a bit - and it didn't happen again - and the cabin stayed cool.

I've had other cars with Vintage Air systems for years - and have taken them on long trips and NEVER had this happen. I think there's something that has changed or gone wrong with their units "recently"...It was implied to me that this was the second or third unit recently with this same "defect" that had to be remedied.

Originally Posted by Rob@restomodair

69hugger,
Sorry you are having issues with your a/c system. You should be concerned; condensation dripping inside your interior is NOT normal. There are 3 reasons why this may have happen to you.

1. There is a crack or a hole in your evaporator. Water always follows the path of least resistance.
2. The hose connection to your evaporator is loose or not connected properly.

If neither of these are the case then you can message me and I will tell you the only thing left it could be.

[dhutton]

I sent the engineering manager of VA a PM with a link to this thread over on the other forum. Let's see if he replies.

Don

[rkleypas]

Greg,

What did they do to remedy the problem? I didn't get around to my proposed repair today and may want to hold off on my "engineering" until I find out how they fixed the problem. Thanks