Smoke out of vents (A/C related)

[c-rad]

The car-- 1991 Nissan 240SX

The problem-- A long time ago (like a year ago), when I was driving in stop and go traffic with my A/C on, all of a sudden a smoky fog started coming through the vents. It left an oily-residue all over them. At the time, I thought my A/C was destroyed so I cut off the belt and didn't use it. Well, a few months ago, I removed the KA24DE to install my CA18DET and when I disconnected the A/C lines on the compressor, it was fully charged still. I figured the smoke and oil residue was from the oil in the refrigerant. Now I want to put A/C back in the car, but I am wondering what went wrong in the first place! I don't want to hook it up and find out its going to happen all over again. Any ideas?

Modified by c-rad at 12:40 AM 7/15/2006
Modified by c-rad at 12:43 AM 7/15/2006

[benemorius]

I hate to tell you this, but it was just condensation caused by the cold air hitting humid air at the mouth of the vents. Aside from being perfectly normal, it's unavoidable as defined by the laws of thermal physics.

[c-rad]

I hate to tell you this, but it was just condensation caused by the cold air hitting humid air at the mouth of the vents. Aside from being perfectly normal, it's unavoidable as defined by the laws of thermal physics.

It never happened before for the year I owned the car. And this is FL, it rains almost every day in the summer and the humidity after a rain shower is well over 90%. It just happened all of a sudden. It was thick greyish smoke. And there was a definite oil residue on the vents. Not just condensation. But I guess I'll take your word for it and hook up the A/C. We'll see what happens.

[benemorius]

Did it waft out and dissipate like cigarette smoke or did it pretty much disappear as soon as it left the vents? Even if it truly was smoke, it couldn't have come from the a/c system itself. Refrigerant vaporizes clear and oil only smokes when it burns. Condensation could be mistaken for oily residue. Of course you were the one who was there so you have to be the judge. I'm just offering speculation.

[c-rad]

Did it waft out and dissipate like cigarette smoke or did it pretty much disappear as soon as it left the vents? Even if it truly was smoke, it couldn't have come from the a/c system itself. Refrigerant vaporizes clear and oil only smokes when it burns. Condensation could be mistaken for oily residue. Of course you were the one who was there so you have to be the judge. I'm just offering speculation.

Well, I guess you're right since it dissipated pretty quickly. Maybe it was just my overreaction of the situation given that it was stop and go traffic and the car itself was running hot and on the verge of overheating at the time. Maybe it was the vinyl protectant that was sprayed onto the vents/dash that surfaced when the moisture hit it and that made it feel oily?