pegasus75

hey guys,

Could you help a newb in diagnosing an A/C Problem?

When I first drive the car and turn on the A/C, it works fine & cool.
But after about 30-45 min driving, the A/C starts to emit vapor and slowly the A/C stops blowing cold air. if I turned off the A/C completely, and wait about another 30-45 min or so, The A/C will be blowing cool air again, well at least for a while, and so the cycle begins

What could be the problem? I checked the refrigerent level regularly to see if I have a leak, and it seems the refrigerant level is normal, nothing to indicate a leak. Anybody has any idea on what else to check?

Thanks for the help guys.

ragsssss

Maybe the belt is loose or needs replacement.
three major componets
compressor
expanion valve (under glove box)
drier

pegasus75

Thanks for the response ragsssss,

I checked the belt condition, and it seems to be in good condition, but I'll check and see if it is "loosed" or not properly tensioned.
I think compressor is OK, but I'll definitely check the other two components, Exp valve & drier. At least if they both checked-out, I can narrow it down to the compressor, which I hope it's not

Thanks and I'll update again.

P_Adams

You're evaporator core is icing up and I suspect the case drain is clogged also (thus the vapor and the system shut down).
ie: Shut it off / ice melts and it starts working again.

Were there any recent repairs to the a/c performed recently?
Sometimes an overfilled system will do this, causing the refrigerant to turn to gas in the evaporator case rather than at the expansion valve.
Moisture in the refrigerant lines can cause ice to form in the expansion valve and block flow also.

P

pegasus75

That make sense P_adams

The only repair that I did recently was to charge the system, and I remembered it was slightly overfilled, nothing serious, and I "release" the system a little (by pinching) to lower the charge. The last time I checked, I think the refrigerant is just right, unless the way I measure it is wrong. Basically, I just plug the gauge into the blue port, start the engine and turn the A/C on high, and read the gauge. Is this wrong?

If it is the problem as you stated, what's the best way to resolve the problem?

Thanks again for your help

P_Adams

Years ago, before the headlong rush to save manufacturing costs, they used to incorporate sight glass inspection ports in the a/c system. You (literally) filled the a/c system thru the low side until you saw the bubbles disappear. No more.
Now the manudactures specify specific amounts of refrigerant - period. no plus or minus.....

Not knoing what catistrophic failures the a/c may have suffered in the past makes it difficult making suggestions. Having most of the a/c components buried and hard to see makes it additionally diffcult as well.

Cheap things first:
Use the recirculation function. This will limit how much moisture pulls thru the system as it draws from inside the cabin.
Clean the evaporatior case drain.
These may be enough to control some of the icing.

If not, I'd suggest having the system put under vacuum and recharged. You may have some moisture in the system and that could help that.

Let maknow how it goes.

P