AC blowing hot air, hissing sound from right passenger side
 

Hello everyone, thanks in advance for any help on this issue.

My AC has worked flawlessy for a very long time. Today when I started the car and pressed the AC button, I immediately heard a hissing sound coming from the passenger side of the car, from what I could tell, behind the dash somewhere. The AC blows hot air while this is happening. If I turn the ac button off, it still blows hot air but the noise goes away. Turn it on, hissing sound immediately starts up.

Any idea what this might be? Compressor? Leak? I will have to try and fix this myself so the more detail the better if at all possbile.

Thanks so much for the assistance.

Nick

Thanks! Does low freon level also account for the hissing sound I instantly get when I press the AC button? It is a sound i have never heard before in this car.

Is there a good guide out there anywhere that would help me do this on my own?

Thanks very much!

Thank you everyone, really appreciate the help!

Keep in mind if you are leaking refridgerant to find and repair the leak. Don't just recharge it without repairing the reason it's low or empty in the first place.

Also if you do find that the system is low on refridgerant avoid using any refridgerant with stop leak in it as this pretty much ruins your system. Any ac shop will generally not service systems that have been contaminated with stop leak also because it can damage their ac machine.

Ok so I bought https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 to refill the freon. Anyone able to give me some advice on how to proceed? I don't even see a place to attach this to.

Incredibly grateful for the help, thank you very much!

Has you system been converted to R-134a? If it hasn't this will not work.

I thougt it was the 1993's that were R12 and the 1994's were R-134 from the factory. Is that not correct? Thanks!

Just checked and you're good. Didn't see anywhere that listed your year in this thread.

1993 = R12
1994-1995 = R134a

http://www.techchoiceparts.com/refri...pacities/mazda

Ok cool thanks for checking, I will update my profile with that info.

Now that I have the right stuff, I have two questions.

1. How do I check the current levels and where do I fill it within the engine compartment?

2. someone abovementioned that if it has the seal stuff in it that it is very bad for the car, is that the truth?

Thanks again!

Try looking at this manufactures video.

I have a 94 fd and the system says r12 so I would check befor mixing refrigerants

Don't use the Freon with the leak sealer in it unless you like ruining your stuff. Bring it to a shop and have it repaired properly. The sealer won't seal anything and will only cause you problems.

Where would it say R12 or R134?

Also, with the refridgerant I got, that nozzle wont connect securely to the line in the car, no matter what i do, I cant get a pressure reading or squirt anything in.

OK if you view my profile you will see the PICTURE i uploaded of the AC system in my car. Is it R12?

Thanks

If the nozzle won't connect then you have r12 connections, you need to purchase a 134 retrofit kit

And don't be surprised if when you put this bottle in that it doesn't work, or does and not for long. If you had a hissing sound it soulds like you have a leak

The best thing to do would be to get the retrofit kit, and rent a vacuum pump and gauges and make SURE you don't have a leak before pumping a $12-$40 can of 134 in it, or more

If u drop the glove box it should have a sticker on the evaporator box saying r-12 or r-134a

If he bought one of those "a/c pro" cans and it won't fit his low side port, narrows it down that his system is still r12