QuestionDear sir, foremost i would like to thank you for taking the time. I have a 97 toyota 4runner. the ac runs cold during 15-30 minutes of driving but after that its just blowing air. I checked if i was low in freon, but seems to have plenty & the compressor seem to engage when ac is turn on. Sometimes, when the temp outside is in upper 80's/low 90's, the ac seem to work fine all day! I haven't serviced it yet but i thought i'd check what you'd recommend for me to do...anything would be greatly appreciated.
Sincerely,
JB
AnswerJB,
Unfortunately there are several things that could cause it to act like this, so I will need to ask a few questions of you in return. Simply do a follow-up on this question, and I would be happy to help in any way that I can.
First... do you have your actual pressure readings from the high and low side, or a way to get them?
Second, when the a/c begins to blow just air, do you notice any decrease in the velocity of the air coming from the vents? Even the slightest amount?
Third, When the system acts up... and you park the truck, turn it off and let it sit 10-15 minutes, do you notice a large puddle of water under the truck on the passenger side? I know it does this when it is running normally, but if it is not working correctly, and there is a large puddle of water under it, that will allow me to determne as to whether or not your evaporator is freezing up.
Have you ever had anything done to the A/C system?
How long has it been since it has started acting like this?
When it is not blowing cold... does the compressor clutch remain engaged?
Fact of the matter is, this could be as simple as a loose connection in your electrical wiring, or as complicated as a restriction inside your low side line causing your evaporator to freeze. The possibilities are endless with the information I have right now, it would take me all night to run dow the possibilities. If you can answer these questions for me it will narrow the playing field immensely.
