AC Hot and Cold

Ok. Let's go back to Summer 2023 - Mid July - finally hot in NY, turn on AC, nothing but warm air for over 30 minutes.

Check this, check that - AC coil kicks in. Must be out of Freon.

Well - it's now late July. Not going to fix it as Summer is more than half done.

Fast forward to Late May 2024 - bring it in to local mechanic (I trust him). Pressure checks the system, says it holds for more than 2 hours. Baffled, says must be micro pin hole and freon leaked out over the years. He recharges system with dye and that's that.

So here's my problem now - I got 4 vents on the dash left to right:

A (next to driver's door)
B (left of radio)
C (right of radio)
D (next to passenger door)

A - Blows cold - like I am use to
B - ehhh some what cool
C - worse than B
D - warm air

What's going on? Any help appreciated. Thanking you in advance.

 

Can't say what is going on in your case (especially if your system was left uncharged for a long period of time, may have moisture, blocked dryer, etc), but that is a classic toyota pickup truck low refrigerant charge condition.

The first place the high pressure liquid refrigerant goes is the portion of the evaporator that blows on the driver.

Not enough refrigerant, there isnt any more liquid by the time it gets to the other end of the evaporator.

Anectodally, every time I have encountered that, adding more refrigerant did the trick.

Could also be clogged airflow on condenser, but doubt it.

BTW, any automotive AC system (except new all electric or hybrids) have an engine driven compressor with rotating shafts and seals. They will always leak some....

 

That's a classic sign of low refrigerant or other problem in the refrigeration side of the system.

You can check the suction line with it running, it should be pretty cold. If it's not you have an issue with the refrigerant side of the system and should have it checked.

 

in a repair shop, the minimum first step is to perform a recharge and determine what quantity came out.

this is done automatically by the machine. You press a button and walk away. It takes about an hour.

After that, you begin to evaluate.

 

I suppose that is at least one way. I have always just approximately followed the guidance in the repair manual myself... I guess I didnt make that clear perhaps

 

If someone charged it with dye, get yourself a $20 UV light and check for the dye. Just follow all the AC plumbing with the light on a dark night. If you don't find the leak under the hood, it could be inside the evap coil which would require disassembly to see.

Have you popped the hood while the a/c is running and felt the lines? i would recommend a thermometer laser for this. also about $20