Probably just needs a refill of Freon. Might also have a leak which would explain the need for a refill.

 

Wouldnt the clutch on the ac compressor be turning on and off if it was low?

 

It should be cycling more when it is low. I have seen systems which will cycle on/off 3-4 times per second when low. It is trying to build pressure. More likely you have a bad relay or clutch cycling (pressure) sensor. Only way to know is to find what your a/c pressure should be and rent a manifold gauge to verify pressures are correct.

 

Not necessarily. If it's too low it won't engage at all.

 

Ok. Ill go buy some freeon and see if that cures it. Thanks

 

Look for leaks first.

 

I bought 2 cans of freeon but need to get the gauge kit to charge the system. My buddy has the kit.

I will look for leaks before I charge it.

 

I prefer to get the cans that have the dye in the oil. It really helps to pinpoint the leaks with a UV light. I've found most of the time that it's the O-rings where the hoses connect to the compressor, condenser, etc. In many cases, I've found people used the wrong material O-rings as well. They use the old R12 nitrile/NBR O-rings instead of neoprene or HNBR which are more-compatible with R134a. Don't ever use viton O-rings in your AC system.

 

Well a little update.

I talked to my aunt who I bought the car from. She had wrecked the car and had it fixed before I bought it. She had the ac radiator replaced but they apparently missed a pinch in the lower ac line. I Looked and bent it back into alignment.

The ac still doesnt work but according to her they might have not recharged the system after replacing the radiator. Is there a way to see if it has any freon in the system?

 

Is there a way to see if it has any freon in the system?

You could press the valve on one of the ports for a split second. If it's fully charged you can tell, just like the air rushing out of the valve on a tire.

It sounds like based on the history that it's not charged and may have a leak. You'll need to pull a vacuum and see if it holds the vacuum after you turn the vacuum pump off. If it leaks, then find and fix the leak before recharging the freon. You may need to add some compressor oil too.

 

The manifold-gauge sets plug into the high/low-pressure ports and tell you how much is in the system. If the AC line was pinched, it very well could have a crack in it. Is it an aluminium one? Very likely bending it back could have been the final blow.

 

If they didn't charge it, then they probably didn't pull a vacuum on it. You'll need to pull a vacuum to charge into. I know on a freon system, it's 30 lbs. Not sure about R-134 though. If you are inquiring about your '97, then I hope by "freon," you mean R-134.

 

He definitely means R134 as R12 is only avaliable to people with clean air act certification or if you're in mexico. I really really doubt his system holds 30 lbs as most systems take around 1 lbs. My 2010 camry uses 19 to 21 oz. The sticker under the hood will inform you how much freon the system can take.

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OP- Your questions point to inexperience. I suggest you just find a good shop and let them do the diagnosis and repair/refill. You could spend a lot of money on this and still not get it working yourself despite the snippets of good advice from well meaning people.

-SP

 

Thanks but that's out of the question. I have less than 1k in the car and it's basically a cheap commuter. It looks like hell due to a recent hail storm and isn't worth much overall.

Anyways, I'm only doing this because it would be nice to have ac. I do most things myself and the only way to learn is to ask.

 

Youtube might be your best friend in this case, since the principles for AC systems are relatively independent of the car. ETCG has a couple of videos about A/C charging that include how to set a vacuum first. Like the guy or not, but it seemed relatively thorough to me (I'm no AC expert).

https://www.youtube.com/watch?v=lglPJuBXVeE

https://www.youtube.com/watch?v=95RdGLFIbL8

 

Throw some freon with dye in it and see what happens.
Get the kind with a gauge so you know how much you need (if any)

 

And don't go around letting a bunch of it out into the air. Its a major greenhouse gas and is a federal offense you know'.

 

NOPE, Actually R134A is the same stuff as in Air Duster cans, AKA Canned air used to clean out computers and such.
Blow off as much as you like when working on your car, it's no different than cleaning out dust in your computer or other electronics.

If you want to go on the SUPER cheap side you could make an adapter since canned air is cheaper than the branded R134 stuff hahah

R12 on the other hand... I would not get caught dead leaking that stuff because the Feds would be VERY upset lol

 

yeah, and the whole global-warming thing has been proven to be a scam to create some new taxes anyway!

 

But you gotta pull that (probably) 30 pound vacuum, before you go shooting anything in there. From what I've been able to find, 30 pounds is a too-tall order for anything equal to, or less than, a Mighty Vac.

Then, actually before all of that, there's the question of oil... Is there enough in there now? You need R-134 compatible oil, which should be a cinch, because the old ester oil for R-12 systems can be a challenge to find.

 

Well a little update.

I pulled a vacuum on the system and it when I shut it off, there is a leak. I guess I will be getting some dye and putting it into the system.

 

If you find it to be a leak at the line fittings, you will end up buying an o-ring kit. Although it will be extra work, your best bet would be to completely remove all of the lines in the front (from the evap core at the firewall forward) and change out every o-ring. Think of it this way, if one of the o-rings is at the point of failure, they are all prone to failure. Plus, you have already opened the system up to the atmosphere anyways, so you might as well replace everything at once and save yourself the trouble down the road

 

Where is the cheapest place for an o ring kit?

 

The local parts stores will also have a kit that includes the gasket for the compressor plate where the inlet and outlet are. You'd want that over the generic set if you want to replace every rubber seal there is.

 

Your local auto parts store would have them in their A/C section. Usually comes in a clear box with a variety of o-ring sizes. They will likely be the R-134a compatible green HNBR type. Should run you about ~$5

 

When I did my AC system. I had to replace the compressor and the condenser.
I replaced every o-ring I saw and lubed it with White Lithium Grease. Mine didn't look too bad, but I replaced them anyway.

If your system has been open to the atmosphere for a long time. Make sure when you refill it to put some R134a compressor oil in first. Then the R134a.

 

Just to clarify, R134 is not the same as R134a. While both are tetrafluoroethane, they are isomers with slightly different physical arrangements:

R134 is CHF2-CHF2 symmetical 1,1,2,2-tetrafluoroethane
R134a is CF3-CH2F and arranged as 1,1,1,2-tetrafluoroethane
​

R134 originally was used as a replacement for R12 freon, but was found to be not as effiicent. R134a was its successor and ends up being more efficient than R12, thus the lower amounts needed in retro-fitted AC systems.

R134a's not exactly benign however, it's on the list of greenhouse-gases and has been banned in the EU since 2011. The SAE has proposed HFO-1234yf CF3CF=CH2 as its replacement. It's unfortunate due to its fairly inert chemical nature, that it's not a more controlled substance. R134a has been implicated in numerous teenage "huffing" and "dusting" deaths: Snopes.com - Dusted Off. Then again, asphyxiation and death can also occur from CO2, N2, propane, pillows, plastic-bags, etc. anything that prevents O2 in the air from getting into your lungs (doesn't even have to chemically react with anything).

BTW - I've used propane from my BBQ tank as a refrigerant in cars and it actually works! But I would be worried about leaks and potential fires, so no converting my engine into a BBQ allowed!

 

Well I bought some freeon with dye and the leak was a crack where the line was originally bent. I took it off and tried some JB weld. After a few hours I checked it and it was hard. I threw a vacuum on it and it held for a good 30 mins. I decided to charge the system and as soon as I did it began to leak around the weld. Looks like Ill have to buy a new line.

 

If you've got the cash, it probably wouldn't be a bad idea to replace the receiver/dryer, if the system has spent a lot of time open.

 

I know many AC systems don't even turn on when low on freon. Clutch never activates.