Air Conditioner Recharge

[Poppinj]

So I live in the desert and my 06 spec has never had the air conditioner recharged. I had a buddy do it today with some 134a+ articfreeze something or another that I've had laying around for like 2 yrs. After he recharges it I start driving home and the air conditioner sucks. I figure its just to hot, and indeed it does start to cool after I start cruzing, but the car is really jerky, kinda like the A/compressor is kicking on and off, especially in the high 2000 RPM range. After I come to a stop the compressor fells like it shuts of completely sometimes. It's blatently obvious when the compressor is on because the car bogs down, and it just seems like its not staying on for very long, and only after I'm going like 35 mph. I don't know why its not on nonstop.

Does the compressor turn off when it gets too hot, or when you come to a stop, like some sort of safety feature or something? My after market header has no heat shields which I'm sure heats it up. Do I have to wait a while for the recharge to work?

[Jeff Kleb]

Just wild speculation....but is there a chance that he overcharged it? Besides, why would an '06 need refrigerant anyway? My '02 with 95,000 miles and seven summer seasons has never been touched.

I think I'll make it another two months to get through this season, but am going to have to "recharge it" come Spring of 2009. Wal-Mart sells this stuff for less than $20 that is supposed to recharge any R134(a) automotive sytem.

Try using the "Tech" forum, as there may be some mechanics lurking there. Best of luck to you!!

[Poppinj]

I dunno anything about recharging an a/c system. He said it wouldn't hurt to put the can I had into the system since I had one laying around. I'm not sure if you could overcharge it cuz there is nothing pumping refrigerant into they system. Its just the pressure in the can. When he pulled the can off all the excess left in the can of refrigerant spewed out.

[sje0123]

Originally Posted by Poppinj

I dunno anything about recharging an a/c system. He said it wouldn't hurt to put the can I had into the system since I had one laying around. I'm not sure if you could overcharge it cuz there is nothing pumping refrigerant into they system. Its just the pressure in the can. When he pulled the can off all the excess left in the can of refrigerant spewed out.

If the remaining refrigerant came spewing out the guy has no friggin clue. The can has a valve on it so what's left doesn't come out. That stuff isn't good for you or the environment. Don't let this guy touch your car again.

[Poppinj]

Originally Posted by sje0123

If the remaining refrigerant came spewing out the guy has no friggin clue. The can has a valve on it so what's left doesn't come out. That stuff isn't good for you or the environment. Don't let this guy touch your car again.

No, this was a can with no valve, I think. You screw the pointy part of the hose into the can to make it puncture the top. Like this one
http://www.zakproducts.com/clientupl...tore/AC110.jpg

[sje0123]

The pointy part that you screw in is the valve. You turn it in to puncture it, let it out to release then turn it back in to close.

[P.P.H.]

you need a guage to know if your system is low or high. find one then go from there.

[SoonToBeASpec]

Uh ... this guy has no clue. Don't let him work on your A/C system anymore.

Yes you can OVER charge a system.
Yes you can UNDER charge a system.

Look at your A/C system as two parts. A High side, and a Low side. The high side is FROM the compressor (called high side because it is compressed). Freon from the comp. is in liquid state as it runs through the condenser. Once it passes the accumulator and enters the expansion valve it becomes part 2, the LOW side. In the low side (after the txv) the freon changes to a gas as it passes through the evaporator and back to the compressor.

If your system is OVER charged, it will not cool right because it cannot efficiently convert the liquid to a gas, circulate and repeat.

If your system is UNDER charged, it will ice up the evap. There will not be an efficient gas / liquid ratio (opposite of an over charge).

the only way to tell what your A/C system is actually doing is to hook an accurate gauge set up to the high and low side.

Also, a general rule of thumb is a 20 degree split. The average ac unit can cool an area to about 20 degrees below ambient temp. So if its 116 outside, dont expect it to be 65 in your car.

[Poppinj]

Ok thanks. I'll take my car to the hobby shot tomorrow and ask the mechanic to hook a gauge up. If the car is overcharged will it blow a gasket or do any harm, or just not cool efficiently? If it is overcharged, is there a way to let some of the 134a out?

Originally Posted by SoonToBeASpec

Uh ... this guy has no clue. Don't let him work on your A/C system anymore.

Yes you can OVER charge a system.
Yes you can UNDER charge a system.

Look at your A/C system as two parts. A High side, and a Low side. The high side is FROM the compressor (called high side because it is compressed). Freon from the comp. is in liquid state as it runs through the condenser. Once it passes the accumulator and enters the expansion valve it becomes part 2, the LOW side. In the low side (after the txv) the freon changes to a gas as it passes through the evaporator and back to the compressor.

If your system is OVER charged, it will not cool right because it cannot efficiently convert the liquid to a gas, circulate and repeat.

If your system is UNDER charged, it will ice up the evap. There will not be an efficient gas / liquid ratio (opposite of an over charge).

the only way to tell what your A/C system is actually doing is to hook an accurate gauge set up to the high and low side.

Also, a general rule of thumb is a 20 degree split. The average ac unit can cool an area to about 20 degrees below ambient temp. So if its 116 outside, dont expect it to be 65 in your car.

[SR20DE_MAN]

http://www.xanga.com/item.aspx?user=...&uid=213551321

http://www.id-usa.com/video/aug04/sy...Media-DSL).wmv

^ You can do it yourself as well. Follow the instructions on that site. It applies to a Miata, but it's pretty much the same thing for a Sentra. You can get that can at Pep Boys.

Make sure that you do the low pressure line with the blue cap. It should be the one on the passenger side of the engine bay. The big fat metal line.

[6th-speed]

I was told before that you don't need to recharge the AC unless it has a leak,since it's a closed circuit that would make sense.
Why would a 06 need a AC recharge ? It's not covered under warranty ?

[Poppinj]

I really dont know much about air conditioning systems. I just know that the heat out here is brutal to cars during the summer. Alot of A/C's just struggle to keep up even when they're brand new. Its fairly common practice around here to "top off" refrigerant. I just figured it wouldn't hurt anything. I'm gonna go to my hobby shot tomarrow to clean the air filter on my cold air because it makes it feel like a brand new car. The idle slowly gets rougher and rougher but after cleaning the filter you cant even tell the car is on. Its just so freakin dusty around here it clogs up pretty quick. They will have a gauge there I'm sure and I can check for free. I'll see if thats the problem. I went outside after my car had cooled off completely and it worked fine. I think the car was just hot earlier. I dunno.

[6th-speed]

Originally Posted by Poppinj

I really dont know much about air conditioning systems. I just know that the heat out here is brutal to cars during the summer. Alot of A/C's just struggle to keep up even when they're brand new. Its fairly common practice around here to "top off" refrigerant. I just figured it wouldn't hurt anything. I'm gonna go to my hobby shot tomarrow to clean the air filter on my cold air because it makes it feel like a brand new car. The idle slowly gets rougher and rougher but after cleaning the filter you cant even tell the car is on. Its just so freakin dusty around here it clogs up pretty quick. They will have a gauge there I'm sure and I can check for free. I'll see if thats the problem. I went outside after my car had cooled off completely and it worked fine. I think the car was just hot earlier. I dunno.

Advise: SIR,STEP AWAY FROM THE VEHICLE,JUST DRIVE AND LET PROFESSIONAL DEAL WITH THE PROBLEMS.

[2001se2.0]

Last recharge I did I also added oil to the low pressure system (not on the Sentra, this was a 96 Civic). A good charge means nothing if the system isn't lubricated.

[sr20desentre]

Yea my uncle has a license to use R12 refrigerant and a134, and it does seem like it is more than likely overcharged, when ever you recharge it there should always be some gauge that gives you the pressure that's in the lines, id be careful cause I remember we ended up trashing my sisters civic AC compressor like that. Hey I thought R12 was the one that was bad for the environment, which is why they switched over to the 134?