a/c issues part III (or IV OR V) (1 Viewer)

[inacoma]

I ended up putting about 2 ounces of freon into the system before the bubbles quit. It's colder, and it still works

For you guys afraid to put your own freon in, (by the way freon is also R134 and a variety of other compounds:

http://computing-dictionary.thefreedictionary.com/Freon)

I find it inconceivable that adding 2 ounces to a weak system would hurt it...

I added a whole lot more than 2 ounces today I used a gauge and filled it to 45 psi. my bubbles then went away as well. will see how it works in the heat tomorrow.

thanks for your assistance.

kumar

 

[medtro]

Kumar,

My local Autozone store has AC gauge for loan, may be your Autozone stores have it too.

LOW line goes to firewall

HIGH line goes to condenser

 

[inacoma]

Kumar,

My local Autozone store has AC gauge for loan, may be your Autozone stores have it too.

LOW line goes to firewall

HIGH line goes to condenser

My autozone didn't rent them. they only sold them. so I bought a can with a built in "reusable" low side gauge.

Kumar

 

[cary]

yours looks ok. hopefully it feels ok too. i read in my fsm that the site bubble may show some bubbling at extreme temps...and that would be ok. however a lot of folks here don't think the site bubble is good for determining freon levels...except in r12 systems, like yours.

otherwise, yours looks "ok" given what you have provided.

I bought some r134a today with a built in gauge for the low side. I will be attempting to check my pressure then to refill if neccessary when the truck cools down as well as the ambient temperature.

Kumar

DO NOT CHARGE YOUR SYSTEM BASED ON LOW SIDE READINGS. I did some research on this last year and found that this is great way to destroy your system by overcharging. There are some A/C boards our there with lots of information. To keep it short, spend $15 for a hi-side guage and the pressure for the R-134 system should be 2.2-2.5 times ambient tempurature.

Cary

 

[Doc]

Both my cruisers have R-12 systems. The 80's AC is shot. I don't know what the problem with it is, but it doesn't blow cold. Coolish, yes, but not cold. Are there some easy things to check for my system? Can I buy R-12 and charge it myself?

 

[lurker]

Both my cruisers have R-12 systems. The 80's AC is shot. I don't know what the problem with it is, but it doesn't blow cold. Coolish, yes, but not cold. Are there some easy things to check for my system? Can I buy R-12 and charge it myself?

Doc, look at my pictures above I'm pretty sure that my system is R12 (view finder in the battery cab).

It looks like a fish eye, but when the AC pulls (high buttom 4) the system clouds up. My AC is WAY TOO cold, even on 1.

 

[Rich]

...For you guys afraid to put your own freon in...

No fear here. I service my own AC.

What I was attempting to communicate is that a proper and professional approach to servicing an AC system starts with monitoring the low side and high side pressures with the system operating while at the same time monitoring the ambient temp in front of the condenser and the output temp at the dash vent.

There are a number of problems that can result in poor AC performance. If the system already has sufficient or too much refrigerant, then adding more is a bad thing to do.

 

[SteveLCetc]

No fear here. I service my own AC.

What I was attempting to communicate is that a proper and professional approach to servicing an AC system starts with monitoring the low side and high side pressures with the system operating while at the same time monitoring the ambient temp in front of the condenser and the output temp at the dash vent.

There are a number of problems that can result in poor AC performance. If the system already has sufficient or too much refrigerant, then adding more is a bad thing to do.

Can it have too much refrigerant and still have bubbles?

 

[Rich]

Can it have too much refrigerant and still have bubbles?

Yes, one situation where this can happen is if there is air, in addition to refrigerant, in the system.

 

[SteveLCetc]

Yes, one situation where this can happen is if there is air, in addition to refrigerant, in the system.

What's the low side pressure supposed to be?

 

[Rich]

What's the low side pressure supposed to be?

According to Toyota with the following conditions:

Outside air temp 86 - 95 F
Engine at 1500 rpm,
AC blower on high,
AC set to max cool,

then, if the system is operating properly, the low side pressure should be between 21 - 36 psi and the high side pressure should be between 199 - 228 psi.

 

[cary]

Low side should be anywhere from 20-45 psi. Anything below or above indicate operational problems. My recolection and understanding is that low side is checked to see potential problems BUT SHOULD UNDER NO CONDITIONS be used to checked if there is enough charge. That is what a high side guage is for. You can get the hi side guage for about $15 or if you order mail order a manifold with low and high side that allows for reading and charging at the same time for about $60-70.

 

[cary]

According to Toyota with the following conditions:

Outside air temp 86 - 95 F
Engine at 1500 rpm,
AC blower on high,
AC set to max cool,

then, if the system is operating properly, the low side pressure should be between 21 - 36 psi and the high side pressure should be between 199 - 228 psi.

Looks like Toyota does follow the 2.2-2.5 times ambient temp in F for figuring high side pressure. This formula can be helpful if you need to check and the outside temp is higher or lower than the listed temps. Also note, it is easier to charge when it is a bit cooler as the low side pressure will be corrispondingling lower.

 

[inacoma]

According to Toyota with the following conditions:

Outside air temp 86 - 95 F
Engine at 1500 rpm,
AC blower on high,
AC set to max cool,

then, if the system is operating properly, the low side pressure should be between 21 - 36 psi and the high side pressure should be between 199 - 228 psi.

so if it's overcharged, can you just bleed some off with the manifold?

Kumar

 

[Rich]

Technically yes. I expect that US federal law requires R134 to be recovered. I know that it is not permitted to vent R12 without recovering.

 

[Waggoner5]

Kumar,
Get gauges on your tuck an check it correctly. The fact that you did have, but now don't have bubles tells me that it is over filled. This will create very high head pressure on the high side, and in the heat of the day can cause the pop off valve to go, loosing all you freon. Use the gauges, vaccum it out, and start fresh. The next thing that seems to help the 80s cool the best, is to ad a small electric pusher fan in front of the condenser that comes on with the compressor. This modification keeps head pressures down, and low side cooling pressures down. I consistantly see 10-15 degree drops in cooling temps when idling or stop and go traffic with this mod. Its 38 in Silverton right now at 7:00 AM.
Gary

 

[inacoma]

Kumar,
Get gauges on your tuck an check it correctly. The fact that you did have, but now don't have bubles tells me that it is over filled. This will create very high head pressure on the high side, and in the heat of the day can cause the pop off valve to go, loosing all you freon. Use the gauges, vaccum it out, and start fresh. The next thing that seems to help the 80s cool the best, is to ad a small electric pusher fan in front of the condenser that comes on with the compressor. This modification keeps head pressures down, and low side cooling pressures down. I consistantly see 10-15 degree drops in cooling temps when idling or stop and go traffic with this mod. Its 38 in Silverton right now at 7:00 AM.
Gary

I actually do have gauges on the way today. I was definitly going to check it correctly , but wanted to make sure I could "vent" it and not severly effect the system. Does anyone know if you one can rent a vaccuum machine? I called a few places and no go. I will go have to find one of those fans...I assume any small electric one from autoparts store should do it then wired up with a relay to the compressor (any idea which wire).

Have you already made it to Silverton? Or are you just checking the internet? It may be 38 in Silverton, but's it's Damn hot in Kansas!!!

Kumar
...also getting AC ready for the MOVE to HOTlanta!!!

 

[landtoy80]

I will try and fill the a/c on the TURD today. I am not going to evac the system first as I assume it has a leak. The system is R12. I have a can of R134 oil with seal conditioner.
As it may have a leak, which will leak out first, the R134 or the air in the system?
If the leak is too bad they have a can of metal stop leak for $20 at Autoztone.
I have a guage to read the high and low side. It looks like a tire pressure guage that says high, low or good.
How does air in the system affect the pressure in the system? Will it give a false reading on my guage?

 

[Rich]

R134 oil is not for use in R12 system. Nor would you put R134 in an R12 system unless the system is being converted to R134, which you don't say has been done.

The gauge you have sounds like crap; search on the web for ac manifold gauges. Most AC pros replace leakly seals and do not use stop leak.

Air in the system will not give false reading on pressure gagues. Air in system will result in AC not working properly. If there is air and moisture in system then it needs to be evacuated with a vacuum pump before recharging and the receiver / dryer replaced before evacuating.

The approach you have outlined is not likely to bring you satisfaction.

 

[landtoy80]

I am converting the R12 to R134. The TURD is a turd so if the a/c dies,thats ok.
I did the R12 to R134 on the Previa Van with no evac and no problem. It lasted a year till I sold it.
It blew cold air.

I would never do this on a good running vehicle. But a beater, YES.