another AC thread, not blowing "warm" but not cold

Yeah I'm not really so if you had a gauge you could put on the high side the skinny tube that's going to read over 200 PSI on a 90 some odd degree day you want to look and see if that high side is anywhere near any of that kind of pressure on the low side all you're going to see is 30 32 35 whatever wonderful The high side when things are steady stable or just sitting there after it's been on a few minutes should be around 2:40 something like that and then the other thing to do is when this is happening and you're running the air pull over in the parking lot lift the hood and touch the fat hoes coming from the compressor running up past the front of the engine and going to the inside part of the air conditioner is that fat tube cold and the skinny tube noticeably hotter once the air conditioning stabilizes and it gets cool in the cabin that skinny hot tube will get a lot cooler because it's not moving as much heat out of the cabin because it's cool and stabilized.

 

Obvious sounds like the refrigerant is probably a little again and they may tell you they do not find a leak again.

not always reliable method but if you don’t see shadowy dark spots that have collected dust on the condenser because that is the number one leaker on the Prius. But you don’t have to always have a oil spot to have a leak.

and if you go three times in a row running low on refrigerant and it is not the condenser and there’s a 95% chance it’s the evaporator.

but both of these can be confirmed with a good sensitive refrigerant leak detector.
And supposedly if the last guy you took it to know anything about air conditioning they stuck UV dye in there and hopefully a good brand name that is very reflective . This will help you find the ones under the hood

finding a leak under the dash if I can’t pick it up with the refrigerant leak detector.

I drill a hole in the HVAC case by the gas pedal just below and back from one of the actuator door flap motors.

you could drill one hole not you because it’s too easy for somebody who doesn’t know to drill right into the evaporator itself and cause damage.

but with experience I know exactly where the drill and place a hole behind the evaporator and another hole in front of the evaporator on the case and then I stick a borescope inside the evaporator case and I can take a visual look for confirmation and see the oil buildup and the dust stain on the evaporator confirming that it is a leak in evaporator.

but usually my refrigerant leak detector is so sensitive it literally pics of parts per million of refrigerant in the air and I could pick it out in the dash Vents with my electronics refrigerant leak detector.

it’s not your regular every day automotive refrigerant leak detector or eBay or Amazon especially designed for doing parts per million sensitivity that’s why it’s $1000.

I can pick up all the leaks all the other guys miss at the other shops. .

if you have a local HVAC shop you can ask him to do a high-pressure nitrogen test The system up to 175 or 200 psi of pressure and use the ultrasonic leak detector that usually finds leaks that only leak at high-pressure that you cannot check for withstanding refrigerant pressures because they can never get that high because some leaks actually turn off at lower pressures.

and if you have a really good shop they have helium or hydrogen leak detector that uses dry nitrogen and 5% helium or 5% hydrogen and they could drive it up to 200 psi and then you have the best of both worlds.

Because you can use a leak detector that is ultrasensitive and you’re using a molecule size of a gas that is 10 times smaller than a Refrigerant molecule and it’s very easy for the pass through the smallest whole much more quickly and be detected by a sensor.

But it’s difficult to find automotive shops that have that equipment because most owner of the shops or either ignorant don’t know what exist , lazy don’t want to buy it and learn how to use it , or cheap they don’t wanna spend the money to purchase it.

that’s one of the biggest problems with our automotive industry