A sniffer may be needed to locate a small/hidden leak.
Verify that there was dye added, any evidence in the charge port. Depress the schrader valve to release a very small amount if in doubt.

Notice any change in the charge pressure?
Since shop did the recharge with dye in order to locate a leak, ask them to take a look. You may be missing something.

 

Why not start with buying a set of gauges and simply checking the pressure? There are a number of reasons the system could stop working, of which pressure is just one cause. These include the compressor or clutch failing, an electrical problem with the system, a part failure (expansion valve, pressure switch), or low pressure (leak, etc.), and more.

 

I was going to suggest your blend door could be worn out but it blowing colder immediately afterwards rules that out.

I think it's likely that your leak is either at the valves, the compressor, OR you could also have a small leak in your condenser from a rock, there's actually a TSB for the latter.

 

Gauges are the place to start, over pressure will shut them down as well.

 

Take a look at the drain tube, if it's accessible from in the car then pull it off and look at the AC box drain for dye, if there's dye then you need a new AC core, if you can't get to it in the car then it needs to be looked at on a lift as it's near the bottom of the 'fire wall' toward the passenger side.

 

+1. Listen to Bitter.

 

Hey guys,

Thank you for all the input. I did buy some gauges ($60 @ Harbor Freight) and there was no charge left in the system; like I expected. Seeing how it blew cold for 2 weeks after I recharged it before blowing warm again; I figured. Bitter you were spot on. The drain line near the passenger side of the car had dye in it. So I am going to be replacing the evaporator core as well as the expansion valve while I'm am in there. Any suggestions on things to look out for, or seals, parts, etc. that don't come with the evaporator or expansion valve that I will need to replace when I do the job. Also, is there any tools that would make the job easier or quicker? Thank yall for all your input. Even if I didn't respond back to you I read your post and took it into consideration. I haven't found a good video of a dash removal for the 9th Gen Corollas so I plan I making one when I do this job. I will post it on this website if I can. I am new to this website so I am not quite sure how to post a video on here, but sure I will figure it out. Also, any specific brands of a/c parts that are better than others. I plan on going through RockAuto or Partsgeek. Also, should I add oil to the system when I replace an evaporator core and expansion valve. Again, appreciate the feed back and hopefully this experience is helpful for others trying to diagnose there a/c system.

Recap: A/C started blowing warm, Recharged with dye, inspected with UV flashlight in dark garage, no visible signs of leaks in the engine compartment, got advice on here to look at the a/c drain line near the passenger side firewall, found presence of dye in the drain line, diagnosis: leak in the evaporator core. fix: replace evaporator core and while I've got the dash out I will be replacing expansion valve and cabin air filter as well.

RockAuto: Evaporator Core: $94.79 (DENSO 4760024 {#8850102180}), Expansion Valve $31.99 (DENSO 4750512 {#8851560150, 8851560190}), Cabin Air Filter $5.54 (Denso 4532039 {#8856802020}), and Heat & Air Conditioning : A/C System O-Rings, Seals, & Gasket Kits $10.33 (FOUR SEASONS 26816 AC System Seal Kit).

If any of yall have videos of 9 Gen Corolla Dash Removal or evaporator R&R diy post them on here.

 

I haven't found a good video of a dash removal for the 9th Gen Corollas so I plan I making one when I do this job. I will post it on this website if I can. I am new to this website so I am not quite sure how to post a video on here, but sure I will figure it out. .

Thanks from the future for all the info and part numbers. Did you ever make that video or find a good one? (Assuming you are still here)

 

Glad you found the leak, also sucks you found the leak. Get some strong de-greaser like Purple Muscle or Simple Green and mix it 1:1 with water and thoroughly clean the HVAC box out to remove any left over dye oil and accumulated dirt. I suggest replacing the dryer, it's in the AC condenser on that car and it IS serviceable, they sell kits on Rock Auto. However if the condenser has a lot of damaged fins on the lower half you may as well just replace it. Nothing blows colder than AC with a new condenser and a proper charge. You'll need some compressor oil as well, should take ND-8 oil which is just this stuff:
https://www.amazon.com/gp/product/B00C8747O8/ref=oh_aui_detailpage_o05_s01?ie=UTF8&psc=1
Use it to lube the O-rings on assembly and carefully press things together so you don't bonk the rings up by pinching them and create a leak. I even went so far as to get O-rings from my local dealer when I changed the condenser on my Celica and ended up having a leak for some reason and had to find a fractionally larger O-ring. So strange!

 

Do I need to add oil to the system when recharging if I replace the evaporator, expansion valve and the condenser? If so do you know how much, or is the oil just needed for the O-rings? Do you know of any good videos online for either one of these jobs (evaporator or condensor R&R). Condenser seems pretty simple, but the evaporator is going to be a learning experience for me. Please feel free for any other tips!

Do you think it's risky to use aftermarket o-ring kit?

 

Also, what is the best affordable R134a with dye to use?

 

Any AC dye kit will be fine, yes you need to add oil to the parts, just drain out what's in them to a cup and add that much back in with new oil + the dye oil you add will have you right around the correct amount of system oil.

 

Send me a PM and I can get you the repair manual documents for dashboard removal.

 

Hey there, I was hoping to start the dash removal tomorrow morning. I know it's last minute notice but is there anyway I can get that removal guide from you asap. Thank you for your time.

 

Parts store o-ring kits are ok. As others mentioned, definitly replace the receiver-dryer. Consider leaving the old receiver-dryer temporarily to test the system. I'd leave the dye out (just plain refrigerant without any sealer or dye), but others would want to put it in to help future diagnosis. Change all the o-rings you can get to and yes oil them first.

You might want to check with a shop that will evacuate the system (of air and moisture) and recharge with the correct amount of refrigerant and oil. Usually $100-120.

 

I think some stores you can rent a gauge set and a vacuum pump, that would let you remove the air yourself and charge it by pressure readings which can get you very very close to a correct charge, close enough to be fine. Dye should be added, it's the easiest way to spot a leak, not all dye have leak seal crap in it, get dye without that junk.

 

I pump air in the system to check for leaks. Some freon is still there to allow using freon detector.
Spray bottle with dishwasher solution.
Drain pipe and condenser with detector, everything else with spray.
sometimes compressors leak in the middle of clutch.

 

Is there a freon detector you recommend?