2020 Toyota RAV4. AC worked fine last Summer/Fall, first time I went to use it this Spring, Nada.

Was at the dealer for a recall anyway, so had them check it. No coolant (freon or whatever they use these days). They say it passed the leak check (pulling a vacuum on it, I assume) twice and works fine with a recharge. They did include some dye with the recharge so if it craps out again it should leave some signs.

Two questions:

1. If it's not a hose/connector/o-ring/seal, where the hell did it go?

2. I'm assuming the dye will show up under UV light if there is a leak? I have a UV flashlight for curing super glue, I plan to scan around under the hood occasionally just to keep an eye on things.

My guess is a seal dried out, allowing the refrigerant to leak out. When they recharged it, the seal became pliable again and sealed properly.

Wild ass guess...

Vacuum test is one thing, a test under pressure is another.
Could have leaked out of the compressor shaft seal.

I did a leak dye fill on my vette and shined my UV lamp on it.
The compressor glowed up like a black light velvet elvis poster around the housing seals.

That green Dye doesn't need a light, it almost glows.
I pressure test with nitrogen at 350 psi then vacuum.
Along with the connections and such check the HVAC drain for green Dye.

Pinhole in evaporator or condenser.
Or you blew a Seal. (unless you were eating ice-cream while the mechanic was looking it over...)

SC is right about finding the source.

Typical mechanics today. It is a sealed system so it has a leak somewhere. They should have found Ben the leak before recharging, they did not fix anything. Whatever caused it will happen again.

All of the failed shaft seals I have seen will hold pressure but fail the vacuum test.

quote:

Originally posted by mrvmax:
Whatever caused it will happen again.

That's my thinking. And when that happens, it better be fixed for free (plus parts as/if needed) or I'll go all Karen on the Service Manager.

quote:

The compressor glowed up like a black light velvet elvis poster around the housing seals.

Thank you, thank you very much!

The first day on recent trip, our 2012 Odyssey's A/C worked great. The next morning, it didn't work at all. I took to a guy who, for $50, hooked up some gauges, recharged it and said it seemed to be holding pressure. He said if it stopped working in the next two months, he'd credit the $50 towards finding the problem and fixing it.

It's worked great since including the whole 1,500 miles back to MI and the 300 miles to the airport in Detroit. Reading online says that car A/Cs use flexible hoses and orings that aren't used in refrigerators or home ACs and that those hoses and o-rings allow refrigerant to leak out over time. I don't have a clue if that's true, but it'll only cost me $50 to find out.

quote:

Originally posted by trapper189:
I don't have a clue if that's true, but it'll only cost me $50 to find out.

I was a little breathless when they quoted me $189 for diagnose and recharge, but I was there and I wanted it fixed. I've got a local guy that I'm pretty sure will treat me a lot better if it comes to that.

quote:

Originally posted by sigmonkey:
Pinhole in evaporator or condenser.
Or you blew a Seal. (unless you were eating ice-cream while the mechanic was looking it over...)

SC is right about finding the source.

Marzy had a pinhole in the Juke condenser.
Had to do the dye test on it too.

And the replaced compressor.

Here's how install dye.
I mix it in with the oil when the system is dry.

I do see systems that come in with 0 psi and pass a pressure and vacuum test.
About all you can do is replace the shrader valves in the service ports, add dye and check it later.
Pressure and vacuum testing at ambient temps may not show a leak until the system is in use and seeing temp changes.
Low side line will get cold, high side gets hot along with vibration.

Our machines add oil if requested and the oil bottle gets dye added to it.
The system is pretty saturated with dye from use as it is though.
Probably don't really need to add dye anymore as it all comes out green now.

When a system only holds a pound to maybe a a pound and a half of refrigerant, it doesn't take much of a leak to impact performance or even lose it altogether. Holding vacuum only tells you there isn't a gross leak, not a tiny pinhole one.

quote:

1. If it's not a hose/connector/o-ring/seal, where the hell did it go?

Could also be a pinhole leak in the condenser or even the evaporator core. A member had to have his evaporator done on a 2018 Tacoma a few months ago. This required pulling the dash and the Hvac case so it could be disassembled.

If you want to do some snooping yourself with your black light or even the unaided eye, scan every accessible inch of the condenser, assuming all of it is accessible, not hidden behind bumper cover and shrouding. (This is what makes A/C leaks so much fun.) For the evaporator, there are a few ways. Sometimes you can take out the blower resistor and look in the hole. If you can see it, look around the evaporator drain for a dye trail. You can also look at the condensate water after the car has run a while and see if there is any dye in the puddle.

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And when that happens, it better be fixed for free (plus parts as/if needed) or I'll go all Karen on the Service Manager.

What are you expecting to be fixed for free? The suck & blow evacuation & recharge labor I could understand (they'd likely give you that anyway), but not the labor & parts for fixing the leak itself, nor the cost of the cold juice. And I'm sure the "Karen" business is hyperbole.

quote:

Originally posted by egregore:

What are you expecting to be fixed for free? The suck & blow evacuation & recharge labor I could understand (they'd likely give you that anyway), but not the labor & parts for fixing the leak itself, nor the cost of the cold juice. And I'm sure the "Karen" business is hyperbole.

Correct. I would expect to pay for parts and labor to fix the leak. No comment on the "Karen".

A 2020 model is going to have R1234yf, well over $100/lb. Stupid new cars.

quote:

Originally posted by ScreamingCockatoo:

Vacuum test

Mechanic and I had an interesting discussion about this. When the vacuum leaks, where do it go?

quote:

Originally posted by egregore:
A 2020 model is going to have R1234yf, well over $100/lb. Stupid new cars.

Interestingly, Mercedes Benz had a recall on refrigerant due to its flammability. (Only 9 vehicles were affected.)

Link to article. https://daxstreet.com/cars/148...rant-risk-addressed/

Another article discusses the issue. https://emercedesbenz.com/auto...ant-to-be-dangerous/