a/c freezes every 3 hrs?

Putting my Ac knowledge for homes and in hotels. when ever I found the ac unites would freez up usally was due to pluged filers or the AC condenser/radiator unit was plugged with debris..

Take a look and the front of the car in the ac radiator to see if it is indeed pluged or clogged with leaves dirt and even a big chunk of paper.. Next I would look into the cars ac cooling unit in the heator box. this little "radiator" in the heating box could also be plugged with sludge.

Could be a low refrigerant charge - I think that can cause the evaporator to freeze up..

That caused the evaporator to freeze in my home's A/C.

Jerry

What they said -- low refrigerant or something blocking airflow. I would suspect maybe a "door" isn't opening or some such, especially if this happens with recirc on. Also make sure you don't have all the outlet vents turned off. You probably need to have at least half of them turned on to assure sufficient airflow, especially if you run the fan on low.

Well, I just gopt back from Saturn. They could find nothing wrong, but they did reset my compressor so thta it would cycle on / off more frequently. They said that it would help to prevent the compressor from staying on too long and freezing over. They also checked my a/c cooolant (R134) and the evaporator lines, including the drain tube and said that all was perfect with no clogs and the coolant was neither too high nor too low.

Dan in reply:, the problem occured both with the recirculator on or off, didnt matter, I tried, same result either way, ditto. And I never close any of my vents.

So, it'll be awhile before we go cross-state again, see what happens next time! Thanks for the help everyone!

If it happens with recirc on or off that suggests that recirc isn't working right and a lot of outside air is getting into the cabin. If recirc were working fully then eventually the air in the cabin would become dry and frost buildup would stop.

I suspect the doors are messed up somehow.

is checking the recirc doors a major effort? is it something I can check myself? I am pretty sure that the recirc works ok, as when we are stuck behind a stinky truck (there are lots of them here) and I turn the recirc button ON I am no longer bringing in stinky air from outside.