rollintechno

Hey MF, need your help with a problem.

Short story....

Got my A/C recharged about a month ago. Was fine and all until one day I notice it not getting as cold...it got less & less cold until it was eventually useless.

The time span from when it was first charged and doing fine until the time I first noticed it not cooling properly was about 3-4 weeks. The time span from when I noticed it not cooling properly to not cooling at all was about 2-3 weeks.

This past weekend I attempted to add some DIY leak seal and immediately follow up with a recharge. Neither can would release into the system at all.

I noticed the tensioner that kicks in the belt for the a/c compressor would kick in for 1 sec then release for 2 sec, repeating the process the entire time. Meaning the a/c compressor is only turning every 1 out of 3 sec total.

I feel like there is a coolant leak due to the tapered loss of cool temps over the past month but for the a/c system to not take in ANY leak seal or coolant throws me off. Not to mention, the a/c compressor kicking in for only 1 sec at a time makes me think it could be something else. Don't they usually kick in for at least 5 sec at a time or longer?

Any ideas? I really need to get this fixed cuz driving with no a/c mid-summer SUCKS *****!

cliffyk

Short cycling is almost always a sign of the refrigerant charge being low. However you should get a gauge set to properly diagnose the system--

DRAGUL

If you paid to have it recharged a month ago why are you not taking it back to have it checked out? You just paid for recharging

rollintechno

I didn't pay for anything. A friend that works at a BMW dealer re-charged it for me for free.

Thx also, cliffyk.

LS WHAT

you have a leak, looks at the lines and the compressor and see if you can spot oily residue on them.

DRAGUL

You need to have your friend leak check the system. I am assuming there is a leak, and if that is the case, it only lasted a month. If it is low on refrigerant you have a pretty large leak. You are wasting your money and time trying to recharge the system with a leak that size. You need to fix the leak properly. I highly do not recommend adding any leak seal products to a system. Once added it could cause problems now or down the road. Once put in the stuff can not be removed.

0949er

it it was charged and it slowly lost "coldness" then I would bank off the fact you have a leak somewhere

Kong1965

You have a leak somewhere for sure, and it's to the point where the vacuum has been lost in the system, so the compressor can't pull the refrigerant out of the cans when you try and charge.

The valve the allows the refrigerant to be pulled into the system must have negative pressure on the system in order for the over the counter recharging systems to work.

You can replace the hose that's leaking yourself, but even after you do that, you're going to have to go to a shop that can pull a vacuum into the lines (they call it purging) and they will charge it at the same time.

I only know this because I replaced the compressor on an Explorer once, and after hooking up all the lines, I had the same experience. Compressor turns, hoses connected, refrigerant won't charge system.

I think I paid about $200 to have a shop purge and charge it for me.

It sucks.

cliffyk

There is no vacuum in a properly operating, or dead flat, AC system; in fact it is quite the opposite Once charged the system is pressurized at 80 to 90psi when not operating, 25 to 50psi at the low side and 130 to 350psi at the high side--depending on the ambient temperature, with the higher pressures at higher outside temps.

The refrigerant leaves the can for the simple reason that the pressure in the can is higher than that of the low-side of the AC system.

The vacuum that is initially pulled on a system that has been opened up is to remove and air and moisture. By keeping the system subject to 29inHg or better vacuum for 30 to 40 minutes, the moisture is boiled off.

If the system has leaked down slowly, more slowly then the OPs has, and not been opened up then you don't need to) pull the vacuum to recharge it.

I had a 1986 Corolla years ago that I had "converted" to R134a that had to have a can loaded every two weeks because of its age, and that because R134a operates at higher pressures and had smaller molecules. Drove it for almost two years like that.

------------------------------------
OP, get a gauge set and see what the pressures look like. Here's a good temperature/pressure chart; and a "how-to" read the gauges cheat sheet:





There's a ton of good AC info on the web, also Haynes has a an auto AC system book that is at most FLAPS...

One last thought, you were holding the can upside down when you tried to add it--right?

LS WHAT

hope not