Air Conditioner Recharge [Archive] - B15sentra.net - Nissan Sentra Forum

: Air Conditioner Recharge


Poppinj
08-09-2008, 06:45 PM
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
08-09-2008, 07:26 PM
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!!
:D

Poppinj
08-09-2008, 07:57 PM
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
08-09-2008, 08:19 PM
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
08-09-2008, 08:31 PM
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/clientuploads/directory/basestore/AC110.jpg

sje0123
08-09-2008, 09:13 PM
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.
08-09-2008, 09:27 PM
you need a guage to know if your system is low or high. find one then go from there.

SoonToBeASpec
08-09-2008, 09:34 PM
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
08-09-2008, 10:01 PM
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?
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
08-09-2008, 10:43 PM
http://www.xanga.com/item.aspx?user=Jicko&tab=weblogs&uid=213551321

http://www.id-usa.com/video/aug04/system-charging-(WindowsMedia-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
08-09-2008, 11:02 PM
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
08-09-2008, 11:35 PM
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
08-10-2008, 08:10 AM
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
08-10-2008, 09:04 AM
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
08-10-2008, 11:12 AM
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?

JCW355
08-10-2008, 01:09 PM
I'd bet it's overcharged, what color is your dash? Is it exposed to sunlight when your parked? I have the special edition with the charcoal interior and keep the dash out of the sunlight when parked. Cools down quicker. An 06 shouldn't have problems unless it leaks. You might have screwed up by not letting it be a warranty issue. Is it still under warranty?

Jake_reps337
08-11-2008, 12:42 AM
I'd bet it's overcharged, what color is your dash? Is it exposed to sunlight when your parked? I have the special edition with the charcoal interior and keep the dash out of the sunlight when parked. Cools down quicker. An 06 shouldn't have problems unless it leaks. You might have screwed up by not letting it be a warranty issue. Is it still under warranty?

If it's overcharged and he brings it in they're going to know it was tampered with.

I suppose you could always drain the refrigerant and fry the compressor and bring it in.

speedjunkie
08-11-2008, 12:48 AM
and ruin the atmosphere while doing so correct? or were you going to suggest to him to have a certified technician recover the systme and see how much was actually in it to see if it was indeed overcharged, because thats what i was going to say to the guy. Aslo, OP r134a is r134a there is no special blend or kind that will make your ac cool better so dont buy into the hype of getting "synthetic r134a" or "cool booster" or "freeze booster" or whatever the can my say.

SoonToBeASpec
08-12-2008, 04:27 PM
AC systems are actually pretty simple. Do some research on it, you'll learn a ton.

Assuming your system does NOT have a leak, it should be years before you have to cycle any freon. If you do, by chance have a leak, a mechanic can find it by introducing an ultra-violet dye to the unit. The dye can then be seen with a pair of UV glasses (kinda like the ones they see blood with on CSI). OR an experienced technician who is familiar with problem spots can usually pick out a leak with some time and a soap solution that bubbles at the site of a gas discharge.

Also, an AC system CAN be charged from both the high and low sides. Just remember though that the high side can only accommodate liquids, and the low side only gases.

And most importantly, no air conditioning systems cooling, they only remove heat. I would also look at your condenser, make sure it is clean. make sure your fans are in good working order as well.

all things a trained mechanic can diagnose / repair.

6th-speed
08-12-2008, 04:33 PM
AC systems are actually pretty simple. Do some research on it, you'll learn a ton.

Assuming your system does NOT have a leak, it should be years before you have to cycle any freon. If you do, by chance have a leak, a mechanic can find it by introducing an ultra-violet dye to the unit. The dye can then be seen with a pair of UV glasses (kinda like the ones they see blood with on CSI). OR an experienced technician who is familiar with problem spots can usually pick out a leak with some time and a soap solution that bubbles at the site of a gas discharge.

Also, an AC system CAN be charged from both the high and low sides. Just remember though that the high side can only accommodate liquids, and the low side only gases.

And most importantly, no air conditioning systems cooling, they only remove heat. I would also look at your condenser, make sure it is clean. make sure your fans are in good working order as well.

all things a trained mechanic can diagnose / repair.

Following that thought I believe that Nissan already has introduced dice into the system so it can be seen with uv light in case of a problem.

orangelloSE-R
08-12-2008, 04:55 PM
introduced dice
Uuuuuuuuuuuuuuuuuh, Wut? Like fuzzy dice er what?

Poppinj
08-15-2008, 10:00 AM
Thanks for all the help guys. I've learned quite a bit about air conditioners through all my research, which is what I should have done in the first place. I took it to a mechanic and he did a system service for 70 bucks (vacuum out the old plus a refill with lube and dye to make sure I didn't blow a gasket or something). He said I was overcharged by 8 oz, which is apparently a lot since the whole system only holds something like 18oz. Luckily I didnt hurt anything else and the A/C is working fine.

So if a system is overcharged it will wreak havoc on the compressor. While it was overcharged the compressor would kick on and off frequently, and it would really bog down the engine. While working correctly it will just be a slight dip in RPM's them a return to normal, but when it was overcharged it was awful. While idling at 750 RPM's the compressor would kick on and drop it to like 500 or so which would really make the car shake. Its like it took a lot more for the car to use the compressor. I dunno. Its fixed now and I got to learn a lot about A/C's for only 70 bucks.

txspeccer
08-15-2008, 10:03 AM
Excellent. Glad it didn't cause any bigger problems that would have lead to huge $$$$ outlays.