Mike Oxbigger

My car's A/C started shuddering increasingly since this time last year. The a/c isn't as cold as it should be and it constantly cycles on and off every 10-20 seconds. It also vibrates or shudders more than normal. I just bought a recharge kit thinking I was low and needed to fill her up since she's a 96 accord ex. The guage read that I was in the blue which meant my a/c had enough R134a and didn't need recharging. So now I'm stumped. Anybody have any ideas???

Mike Oxbigger

bizump

JimBlake

Plugged evaporator core? Plugged expansion 'valve'? Maybe the receiver/dryer spilled it's guts into the line causing the exp. valve to plug?

It's a good thing you didn't just add a can of refrigerant without looking at the pressure gauge...

mohamed_ibrah

It's definitly not the latter...reciever dryers don't quite "spill". For something like this, it definitly could be a clogged something...whatever. I assume you hooked up the gauge to the high side since charging is usually done from that side. Depending on what the low side pressure is (higher or lower than normal) that will give a basis as to possible causes.

Essentially, though the only way to figure this one out is to have a professional look at it. If you live near Sacramento, CA, I would gladly check it out for ya for the cost of your gas coming to my school.

Mike Oxbigger

FINALLY, I FIXED IT!!! wOOOt!!!! It turned out to be my battery. Went up to autozone and had the battery tested.....bad battery. Replaced it and a/c is back to normal.

Mike Oxbigger

well, its not cycling on and off like crazy but its still not as cold as it should be and when the compressor engages it vibrates quite alot, more then i remember. i was riding around in 72 degree heat, full sun, a/c cranked to max with the air circulating instead of fresh, and even after 20 minutes, it still didn't cool down like it should. is this strictly a compressor problem? did putting the compressor through the extra stress of not having a constant power supply level from the battery cause harm to the compressor?

mohamed_ibrah

Not cooling properly can be a mixture of things...overcharged, undercharged, improper temperature blend door, yada, yada, yada.

One thing you could check is the compressor mounting bolts as you say the thing vibrates alot, and no you didn't harm the compressor by not having a complete battery load to it. But like I said before...take it somewhere and have someone with the right tools check it out. Usually an A/C to be functioning properly, is supposed to lower the interior temperature or climate of a vehicle by at least 20 degrees from outside ambient temperatures (you can check this yourself if you want). An a/c shop, like I said, will check the charge levels, compare high and low side pressures, and center duct temperatures to a vehicle specific chart to determine if there is proper function and it's simply the a/c not being efficient in the design.

Mike Oxbigger

I thought your supposed to check the charge level on the low side ie. the larger of the pipes. thats what my recharge kit said to do at least. any idea on what somebody would charge to check out the a/c system?

mohamed_ibrah

Depends on what kinda of refrigerant you have in there. More than likely you have a R-134a since you said you picked it up at the auto store. To check the charge level, ACCURATELY, you're really only limited to evacuating the system and seeing how much you pull out, vaccuming (this does no harm and in fact benefits you're system to remove moisture and air), and recharging. I don't get those aftermarket gauges...all they can tell you is how your pressure is, not how much refrigerant is in the system, even then low side pressures are usually in a TXV system somewhere in the vicinity of 25-44 psi, when working, and I think it is something like 70 psi, when both sides equalize and are not operating. Those kits are great for the backyard mechanic who is going to sell his ride...but for someone who is going to keep his/her ride, it better to do it the right way, especially since those kits (if you look on the bottle) will contain sealer and dye (which is really not good for the system, well the sealer at least isn't). In fact, we have to check to see if a system has sealer, if it does, we can't do squat to the system and it must be taken somewhere where someone has a scavenger unit to evacuate the system of the refrigerant.

I believe charging with a proper machine is done through the high side, I'd have to look on my machine to be sure (it normal has a valve switch that you open to charge an a/c on one of the sides). Obviously those aftermarket kits maybe different, and I would say refer to the instructions for it.

I have seen shops charge $39-$79 for A/C diagnostics, considering that this is supposed to be an hour worth of labor. If he adds refrigerant to the system, they will charge you for that. I don't know what it is in the current market, but where I am training at, they give it to us at cost for $0.50 an oz. and R-12 is $3.00 an oz, and believe me that is cheap. Make sure they also add the same amount of oil that they pull out during evacuating, I believe the Honda uses Nippondenso-8 or 9 oil, or more commonly known as PAG oil.

GenXer

One thing to check (that's free), is to see if you have road gunk collected in your condenser core. I dropped the head pressure on my old Civic by 75 psi, just by cleaning it out. That definately made it cool better too!