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DIY Need to repair the Air Conditioner

I recently was told there was some fluid leaking from the car, no residue was left behind so it was either water or something else that isn’t oil based. Out of chance I tried to use the AC the other day and found it to do nothing but blow the air… So next task for me and my car will be to get that up and running properly. This is my first time touching the AC, not sure where I should begin to diagnose the cause for the failure. What is the likely reason for the failure (most common cause)? What is a good plan of action for narrowing down the source of the failure?

The most common cause is your refrigerant level is low . . . so low that the compressor is probably not even engaging

And that is probably due to a leak

Sometimes the source of the leak is obvious, such as a greasy condenser, manifold hose, or compressor. Other times, the source of the leak can’t be readily seen, such as an evaporator

Most likely cause is low refrigerant. Freon was use in older cars. R12 in newer. They sell do it yoursel refill cans for r12. Usually a slow leak is why it’s low. You can get a can with dye. You can see where it is leaking with a blacklight.

Freon is DuPont’s trade name for R12 refrigerant used in older vehicles.

R134a is the refrigerant used in today’s vehicles.


Honestly, while I absolutely support DIY adventures, air conditioning systems require specialized equipment and knowledge to diagnose and repair. I’d suggest you simply take it to a shop that does automotive AC repair work. In the end you’ll probably save money and definitely save aggravation.

But we all use the term ‘‘freon’’ loosely and every one knows.
Do you ever dsipute that you’re going to get a ‘‘Kleenex’’ for your nose ?
Or that you’re putting your leftovers in a ‘‘Tupperware’’ to store them ?
and the list goes on where a trade name takes over the daily terminology.

like ‘‘Google’’ …’’.let me google that.’’ and I use MSN’s Bing

As far as the a/c goes, there’s far too many pieces of the puzzle for a single simple answer.

Given no experience, this is not a DIY item. Like TSMB said, take it to a good independent shop.

I get a tissue for my nose.

I use a storage container

I use a search engine.

But I don’t use Freon loosely.

I just call it refrigerant


DIY repair of A/C is really limited to adding refrigerant without having any training. And even with that, unless you know what you’re doing, you could easily overcharge the system and do more damage. I’d bite the bullet and have a professional A/C technician look at it.

Especially if OP has a newer model vehicle, these newer AC systems are very sensitive to overcharging. If they are overcharged, the problem isn’t that they just stop working. The overcharging will cause internal damage, and bits of metal may well contaminate every single gadget in the system. Repairing a major AC contamination problem like that can run into the thousands of dollars. It’s just not a good bet to experiment like that without having the benefit of experience.

There’s nothing wrong of course with DIY’ing your AC, as long as you it correctly. OP would be wise the first time to simply watch as someone experienced does it, and just ask them to explain the procedure to you as you watch and take notes. Then the OP can purchase the appropriate manuals, tools, and gauges and do it themselves the next time.

Working with A/C can also be dangerous and especially so for a DIYer who admittedly has never worked with those systems.

I’m familiar with A/C and sad to say I got a bit careless with my son’s home central unit a few years back. Caught a refrigerant blast on the tip of my right index finger and it’s still somewhat dead today; more than likely due to frostbite nerve damage. That finger throbbed for 4 or 5 days before settling down and all over a 1 second shot of Freon.

“OP would be wise the first time to simply watch as someone experienced does it, and just ask them to explain the procedure to you as you watch and take notes.”

As much as I hate it, I will succumb to the repeated recommendation to not DIY this without getting someone to show me the proper method firsthand. I’ll find one of my mechanic friends that has worked on A/C systems of recent model cars, and if I cannot find out I’ll bite the bullet and take it to the shop.

That said… it would still be nice to diagnose the source of the problem. I will examine the system for any noticeable leaks and report back any findings, but I’ll refrain from any tinkering.

@ok4450: were you wearing gloves when that happened?

Finding an a/c leak usually requires a leak detector. Not a DIY project.

more bad news… guess it’s all on the hope I have someone I know that has experience with A/C systems.

Find a shop that will allow you to watch while they do it. Most inde shops , as long as they aren’t super busy at that time, would probably allow you to watch. Especially if you bring some donuts.

@tester your absolutely right. My brain was stuck on R12 instead of saying 134a.

@GeorgeSanJose‌, watching a professional A/C tech won’t help much. He’ll use expensive professional equipment to locate and fix the problem. The kind of equipment that the DIY’er can’t even afford to rent.

With liability problems no responsible shop is going to let someone watch while the repair is going on. They might escort you to see where the leak or damaged part is but will take you back to the waiting room.

@Zarathruztra, yes I was wearing glasses but not safety glasses. Just eyeglasses.
This was an impromptu thing and I wasn’t really prepared for it. No gloves either.

Refrigerant getting into the eyeballs can really be bad news as it can cause blindness almost instantly.

A shop should not allow a customer into the shop except under very limited circumstances as the liability issue can be huge.
Even the very limited circumstance can lead to problems.

A cousin here in Mexico had a nice late 90’s Yukon. The gas got low, so he added a bunch. Then, it lost pressure completely. My guess is it blew a hole in the condenser or something. Anyway, it doesn’t work any more and there are no a/c repair people out here.