jay23ls

Gettin pretty hot. 88 lately at around mid April.

Symptoms lol

• Couple months ago, AC blew cold air but would take almost 10 mins to get nice n cold
• Now fans work fine but no cold air just semi cool like my fashion sense. Maybe like 75 degrees
• Compressor seems to switch on and off every few seconds when AC first turned on
• Not sure what equipment removes humidity but that doesn't seem to be working bc I see no water dripping from car

Diagnosis: low on R134?

Questions:

Been seeing some mixed reviews on a DIY charge kits like this -

so Im leaning towards going to a shop. Is the C4 like any Chevy when it comes to the AC so no problem taking it to any good domestic shop?

Last thing, are there common leak areas in this AC system? Its a 94. Thanks

gerardvg

Hi

Is short of R134A, it should not cycle off and on every few seconds.
Check the small round pressure switch for cooling fan request, next to the high pressure switch with two spade terminals on the pipework near the evaporator. I have found they don't last long, i have gone through two of these they leak out the top where the small round electrical plug inserts.

I converted my C4 to R134A around 10 years ago, i replaced all the rubber O rings with the green ones for R134A. I also got the rubber hoses changed to modern barrier type, i have only had two leaks both the small round fan request pressure switch.
Hoses can leak where they are clamped onto the aluminum hose fittings, so make sure you check for leaks there also.

The compressor should only cycle off when the a/c is blowing cold air and the car interior is cool, that is how it is designed to work to cycle the compressor off before too much liquid refrigerant floods back.

You should see 40psi on the suction, revving the engine should not affect the suction pressure much when charged correctly.

Check the evaporator screen is clear, check the heater damper flap actually shuts of any hot air from heater.

You can easily check with some dish washing liquid, put it in a spray bottle with a bit of water. Spray on all hose and pipe connections and look for bubbles, spray onto the pressure switches also.

An electronic leak detector makes it pretty easy to find small leaks, but not many can afford to buy them.

Make sure you do not overfill the compressor with oil, remember only fill around 90% per weight R134A as compared to R12 charge weight.

The C4 a/c is a little on the small capacity side to begin with, icy cold on the highway but can warm up in heavy stop start traffic on a hot day.

Atomic6

If you have just a small leak, like I did, try the re-charge kit with the sealer and oil included in the can. I bought mine for $33 at Walmart and the a/c is freezing me out now. How long will it last?? If it gets me through the summer, great! If not, time to go to the shop.

81c3

If it were me, Id bring it to a shop to properly diagnose it. The A/C system is a closed system. It has to have leaked out of somewhere, like a seal as geradvg stated. To really do it properly, the system should be vacuumed down and refilled using a good set of gauges.
Just my .02

jay23ls

Damn, that's a lot more info that I could have expected. Appreciate it! Will see if I can spot leaks so a shop doesn't try to pull something on me.

jay23ls

I've been reading more on the charge kits and I agree. Especially since the car is so old if the kit hurts more than helps it will prob cause more damage. AC shop here I come..

Silver85

Only problem I have with those kits is that the same ingredient that fills the hole to stop the leak could very likely fill the hole that meters the refrigerant (expansion valve). Then it's a real mess......

QCVette

It sounds like there is a leak somewhere. How much leak we can't tell.

I would try pulling a vacuum on the system (Some auto parts stores have loaner vacuum pumps and guage sets that they take a deposit on and then refund it when you return the tools.) Once you pull a vacuum, see how long it takes to degrade.

If it holds quite a while it is a very small leak and I would try filling it up. Cans of 134 are cheap (I see them frequently for about $4 to $6 per can). It may work for quite a while, or it may degrade by the end of summer. Then you can top it off again if needed.

If it is leaking fairly quick, then you need to find the leak and repair it. Then try charging it again.

I only suggest this because the freon is so cheap and frequently it costs very little to keep them running. I have one car that was warm air, but recharged it lasted about two years and I charged it again. The last time was a couple of years ago, so maybe I will have to charge it again this year. Topping it off like this only cost me $4 for two years. I know it is not the correct way, but it can be the low cost way to keep cool.

Good luck.

Atomic6

Not likely. These companies would be long out of business if they damaged a/c systems. Some have been around quite a long time with many positive results. I'm hoping I'm another. We'll find out by September.

https://www.cnet.com/roadshow/news/a...-conditioners/

jay23ls

I read about the re-charge kits damaging the AC shop machines. If at some point the re-charging has to happen too often you'd prob have to take it in to an AC shop. I'll ask them when I get some sort of quote.

Atomic6

If you have to re-charge more than once a year, that's too much IMO. Definitely a professional repair would be needed. Like I posted originally, I'm giving it a try and seeing what happens. If it lasts all year, great!
Also, if you ask a mechanic if you should try or have it professionally done, I know the answer already. They need the $$, not us saving money.

jay23ls

haha thats true. I got my frugral/don't BS me face down pretty good so they usually give me a pretty honest answer and dont try to upsell me. Im the worst person to try to sell something to lol

Either way I have no idea how much a shop charges but if its an arm and a leg ill start considering a recharge kit.

A Peter C4

In the spring I have seen shops ad for AC service $99. But thats in NH

lucidardor

Typically shops will charge between $69-$99 for "AC Service." These ads are designed just to get you in. The "AC service" is simply a recharge and leak test. They will add florescent dye to to the freon, and if the A/C starts blowing warm, you bring the vehicle back to their shop. When you bring the vehicle back in, they will test the system and diagnose the leak. Then they give you a quote for the repair. From my experience, if your system is leaking you're looking at $600-$800 depending on what's wrong. It's a time-consuming process for the shop, and there's a lot of labor for replacing parts.

ValourUnbound

I'm watching this thread closely as my AC is out too.
Question: if the car is still running r12 and a leak has occurred, do I pretty much have to convert to r134a as r12 is impossible to get? Or is there some exception for older cars that allows me to have and get r12?

lucidardor

You can't buy R12 anymore. Even if you could, it's very dangerous and toxic. You can buy conversion kits at any auto parts store, but you'll need tools to ensure you seal it up and it doesn't leak. Any shop will convert it over for you. If you have no leaks, it shouldn't cost very much. Retrofitting just consists of draining the oil and replacing with the R134 oil and replacing the service ports. Most leaks tend to be around those service ports because of so many DIYers. I think most shops will do the retrofitting when they do the basic AC service for under a hundred bucks.

81c3

R-12 is only dangerous when its let into the atmosphere. Its far better at cooling than stupid 134a..... and... if you know the right people... you can still get R-12

A Peter C4

I thick to convert the R12 to R134 you must capture all old R12 and only AC shops have proper machine to extract and dispose of correctly. DO NOT RELEASE into atmosphere.

sprink94

Take it to an AC service shop and have it converted to R-134. The process involves evacuating the R-12 and replacing the O rings, seals, ports,oil and refrigerant. It may also involve replacing the drier and hoses if they are leaking.

Do this right the first time and avoid yourself a lot of aggravation. Driving a hot 'vette in traffic with no AC sucks !!

Eljay

If your system still has R-12 the gas does not go bad, people will pay you to recover it. They will then re-use it.