Ac froze up? any ideas

[Rhode Island Red]

While on my way back home, on a long drive back from the strip, Iwas running my AC as it was hot. I noticed over time my airflow reduced and the air was getting warmer. When I pulled over for a bite to eat and get gas. I popped the hood and saw the condenser covered in ice . It was ~90 and humid out.

Now last November I had my cam & headers done and this was my first long drive with the setup.

My ideas of what caused it are:

1) Freon was never charged fully
2) I have a freon leak
3) After the cam install last November, the condenser was allowed to be exposed to the atmosphere causing moister to get into the system, so when it gets fully cold, the moister freezes up, choking the system.

Have any of y'all ever happen? What should I do? I can drive with it on, give it a brea, then use it again as a stop-gap measure.

[Injuneer]

Your saying that the condensor panel, in front of the radiator, is covered with ice??????

[Rhode Island Red]

The shiney canister is what I mean, next to the where the traction control module is mounted. is what I mean

[Black97]

Don't know but here are some links http://www.google.ca/search?hl=en&cl...G=Search&meta=

[aburke]

Any of those things you mentioned could cause it. You probably know that if the system was open and left opened for some time, then the dessicant in the receiver/dryer could have become saturated. Like you said, then the moisture in the system freezes at the expansion valve and could eventually plug it up (or keep it from opening fully). There's no way to replace the dessicant other than to buy a new receiver/dryer.

When you're cruising for a while, the cabin cools off, you turn the fan speed down, and the A/C system doesn't have to work hard at all. The R134a isn't absorbing much heat anymore, and the pressures go down. If the charge is low, this will happen quicker, but even a fully-charged system can get low enough to freeze. This is where the low pressure switch comes in to shut the compressor off momentarily. (Keeping it on MAX or recirculate will exacerbate the problem.)

A question I have is why didn't the low pressure switch cycle the compressor instead of letting it freeze? Maybe your switch is bad or has been bypassed.

If you have a set of gauges, you could do a quick check. Set the system on A/C and blower on high with windows open. The expansion valve tries to keep the low side around 35psi (roughly). If it drops to 20 or lower, the compressor should kick off. I know there are all kinds of other things that influence this, but with the A/C on (not max; not recirculate), blower high, windows open, and warm ambient temps, the low side shouldn't get down to 20psi.

If the low side is low, but the high side is cruising around 250+psi, then your cooling fans aren't working or the system is probably not low. Something else is wrong (bad or restricted expansion valve). If the high side is around 150psi and struggling to stay up there, then the system is probably low on R134a. In my '94 Z, one cooling fan is always on when the AC is on. When the high side goes over 250, the 2nd fan comes on. I think the '95 and up runs both fans low speed and then kicks them up to high speed.

Also, don't do this in the rain, or it throws everything off.

[Rhode Island Red]

I'm going to take a look at the pressure this weekend. Hopefully, the case will be it was not fully charged. I hope it's not a tainted desiccant bag in the canister, then I have to dish out the $ to have it professionally done.