adding R134a to a 2002 Sienna

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Old 25 May 2012, 12:28 pm   #11 (permalink)
Jeff Strickland
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Default Re: adding R134a to a 2002 Sienna


"Ralph Mowery" <rmowery28146@earthlink.net> wrote in message
news:w4ednSwXFe2kDCLSnZ2dnUVZ_hydnZ2d@earthlink.co m...
>
> "Michael" <mrdarrett@gmail.com> wrote in message
> news:1d956ab8-6bee-416a-b61a-a48c4ede3982@ra8g2000pbc.googlegroups.com...
>
>
>>How did you wreck a compressor anyway?

>
> The Low side is usually the larger pipe.
>


The Low Side is ALWAYS, not usually, the larger pipe. The Low Side and the
High Side are different sizes precisely to prevent connecting the gauge to
the wrong side.





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Old 25 May 2012, 01:02 pm   #12 (permalink)
Ralph Mowery
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Default Re: adding R134a to a 2002 Sienna


"Jeff Strickland" <crwlrjeff@yahoo.com> wrote in message
news:jpobvb$9qd$1@dont-email.me...
>
> "Ralph Mowery" <rmowery28146@earthlink.net> wrote in message
> news:w4ednSwXFe2kDCLSnZ2dnUVZ_hydnZ2d@earthlink.co m...
>>
>> "Michael" <mrdarrett@gmail.com> wrote in message
>> news:1d956ab8-6bee-416a-b61a-a48c4ede3982@ra8g2000pbc.googlegroups.com...
>>
>>
>>>How did you wreck a compressor anyway?

>>
>> The Low side is usually the larger pipe.
>>

>
> The Low Side is ALWAYS, not usually, the larger pipe. The Low Side and the
> High Side are different sizes precisely to prevent connecting the gauge
> to the wrong side.
>


I have never seen one that wasn't. I just try to advoid some words such as
ALWAYS.

The valves are now differant sizes. Older cars used the same size valves
and the cans were blown up because of the higher pressure side that some
hooked to it. This is why the valves are differant, but not the pipes.


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Old 25 May 2012, 01:46 pm   #13 (permalink)
Jeff Strickland
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Default Re: adding R134a to a 2002 Sienna


"Ralph Mowery" <rmowery28146@earthlink.net> wrote in message
news:5M2dnXrVxfqgJiLSnZ2dnUVZ_rydnZ2d@earthlink.co m...
>
> "Jeff Strickland" <crwlrjeff@yahoo.com> wrote in message
> news:jpobvb$9qd$1@dont-email.me...
>>
>> "Ralph Mowery" <rmowery28146@earthlink.net> wrote in message
>> news:w4ednSwXFe2kDCLSnZ2dnUVZ_hydnZ2d@earthlink.co m...
>>>
>>> "Michael" <mrdarrett@gmail.com> wrote in message
>>> news:1d956ab8-6bee-416a-b61a-a48c4ede3982@ra8g2000pbc.googlegroups.com...
>>>
>>>
>>>>How did you wreck a compressor anyway?
>>>
>>> The Low side is usually the larger pipe.
>>>

>>
>> The Low Side is ALWAYS, not usually, the larger pipe. The Low Side and
>> the High Side are different sizes precisely to prevent connecting the
>> gauge to the wrong side.
>>

>
> I have never seen one that wasn't. I just try to advoid some words such
> as ALWAYS.
>
> The valves are now differant sizes. Older cars used the same size valves
> and the cans were blown up because of the higher pressure side that some
> hooked to it. This is why the valves are differant, but not the pipes.
>
>


R134a ports have always been different sizes. Some R12 cars might have had
ports that could be confused, but I was not playing with R12 so I can't say.
But I've never seen a R134 system that was not both different from high to
low, but also different than R12 so there is no way to put R12 in without
working hard to do lots of things wrong.




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Old 26 May 2012, 08:02 pm   #14 (permalink)
larrymoencurly@my-deja.com
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Default Re: adding R134a to a 2002 Sienna

On Wednesday, May 23, 2012 11:05:53 PM UTC-7, Michael wrote:
> I have the exact same problem as this guy, and I'm wondering if the
> solution is the same.
>
> http://www.toyotafans.net/2004-sienn...cold-t4400.htm
>
> I've seen cans of R134a at the store, and I'm wondering how difficult
> this is to do. What are the specs on the minimum pressure at the low-
> side charging port? This doesn't seem to be specified in the Haynes
> manual I've got.
>
> I'm guessing I should get a can of R134a that has a pressure gauge, so
> I'll know how much refrigerant I need to add... if any.
>
> Also, where exactly is the low-side charging port? Again, the Haynes
> manual isn't very clear about *where* it is.


Haynes sucks. Chilton's sucks. AutoZone.com sucks but is free, so try them.
PDFtown.com has some Toyota factory manuals.

A website dedicated to car A/C: www.aircondition.com

Don't R-134A systems use different size fittings for the low and high sides, meaning you don't have to worry about this? But to confirm, run the engine at about 1500-2500 RPM with the A/C on high, and feel around the charging ports. The low-side port is cold, the high-side port is hot.

You really should get an R-134A guage set and a couple of A/C or food thermometers and charge when the outdoor temperature is around 70F - 80F. Some car A/C systems are really touchy about the right amount of refrigerant, soshops will often pump out all the old gas and weigh the amount of gas theyput in.

DO NOT OVERCHARGE THE SYSTEM!

This is my half-arsed way of charging:

Check the accuracy of the 2 thermometers by putting them in a glass of well-stirred ice water while their tips touch, to verify that they read identically. Tape the tip of one thermometer to the inlet pipe going to the evaporator coil, the other to the outlet pipe. This should be near the firewall.. Make sure the thermometer tips make good contact. Run the A/C on high and idle the engine at about 1500-2000 RPM, and the temperature readings should drop. The outlet temp will be higher than the inlet if the system is undercharged. Open the R-134A can's valve slightly to SLOWLY charge the system until the outlet temp is almost as cold as the inlet temp, or the pressure readings are right, whichever comes first. Try to charge while the outdoor temp. is around 70F - 80F because in hotter weather you need to undercharge the system to prevent excessive pressure. Before connecting the hoseto the low-side charging port, open the R-134A can's valve slightly, to purge the air out of the system, and don't close the valve until hose fittingis attached.

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Old 26 May 2012, 08:16 pm   #15 (permalink)
larrymoencurly@my-deja.com
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Default Re: adding R134a to a 2002 Sienna

On Friday, May 25, 2012 9:26:21 AM UTC-7, Jeff Strickland wrote:
>
> I went over to Wal-Mart, and I noticed the cans with a pressure gauge
> have a nice table printed on the can as to what the pressure should
> be, depending on the ambient temperature. I also noticed they sold
> cans without a pressure gauge (which were half the price as the ones
> with a gauge). How on earth would you know when to stop, without a
> gauge?!


Temperature difference between evaporator inlet and outlet pipes, emphasis on DIFFERENCE. If you rely on pressure alone you stand a good chance of overcharging the system, especially in warm weather (not that going by evaporator inlet/outlet temperature difference alone will spare you from that), and apparently it takes only a few PSI of overcharge to hurt the cooling performance noticeably.

The directions probably mention always keeping the R-134A bottle upright sothat only gas gets into the A/C, not liquid, and placing the bottom half of the bottle in a pot of warm water (about 90F - 110F) to keep the pressureup (bottle will otherwise get cold enough to form frost on the outside). Make sure you have room in the engine compartment to keep the water pot upright, even while the engine is running and shaking.

BTW buy plain R-134A, nothing containing leak detection dye or compressor oil.

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Old 27 May 2012, 01:29 am   #16 (permalink)
Michael
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Default Re: adding R134a to a 2002 Sienna

On May 26, 5:02*pm, larrymoencu...@my-deja.com wrote:
....

> You really should get an R-134A guage set and a couple of A/C or food thermometers and charge when the outdoor temperature is around 70F - 80F. *Some car A/C systems are really touchy about the right amount of refrigerant, so shops will often pump out all the old gas and weigh the amount of gas they put in.
>
> DO NOT OVERCHARGE THE SYSTEM!
>
> This is my half-arsed way of charging:
>
> Check the accuracy of the 2 thermometers by putting them in a glass of well-stirred ice water while their tips touch, to verify that they read identically. *Tape the tip of one thermometer to the inlet pipe going to the evaporator coil, the other to the outlet pipe. *This should be near the firewall. *Make sure the thermometer tips make good contact. *Run the A/Con high and idle the engine at about 1500-2000 RPM, and the temperature readings should drop. *The outlet temp will be higher than the inlet if thesystem is undercharged. *Open the R-134A can's valve slightly to SLOWLY charge the system until the outlet temp is almost as cold as the inlet temp, or the pressure readings are right, whichever comes first. *Try to charge while the outdoor temp. is around 70F - 80F because in hotter weather you need to undercharge the system to prevent excessive pressure. *Before connecting the hose to the low-side charging port, open the R-134A can's valve slightly, to purge the air out of the system, and don't close the valve until hose fitting is attached.


......

Thanks to everyone for the advice. This is embarrassing, but I think
the A/C is working properly. I didn't realize that for the REAR AC to
work, the FRONT AC button has to be on. I thought that if the rear
knob was pointing at the blue AC button, that should activate the rear
AC. But I didn't realize the rear AC shares refrigerant with the
front AC until I started researching the "problem".

When the front AC is on, the rear blows noticeably colder. I'll do a
temperature check with my thermocouple next time I get a chance, but,
yeah.

Thanks!

Michael
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Old 27 May 2012, 11:05 am   #17 (permalink)
Jeff Strickland
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Default Re: adding R134a to a 2002 Sienna


"Michael" <mrdarrett@gmail.com> wrote in message
news:30363381-2102-418c-bb3a-699f33fd5574@ra8g2000pbc.googlegroups.com...
On May 26, 5:02 pm, larrymoencu...@my-deja.com wrote:
....

> You really should get an R-134A guage set and a couple of A/C or food
> thermometers and charge when the outdoor temperature is around 70F - 80F.
> Some car A/C systems are really touchy about the right amount of
> refrigerant, so shops will often pump out all the old gas and weigh the
> amount of gas they put in.
>
> DO NOT OVERCHARGE THE SYSTEM!
>
> This is my half-arsed way of charging:
>
> Check the accuracy of the 2 thermometers by putting them in a glass of
> well-stirred ice water while their tips touch, to verify that they read
> identically. Tape the tip of one thermometer to the inlet pipe going to
> the evaporator coil, the other to the outlet pipe. This should be near the
> firewall. Make sure the thermometer tips make good contact. Run the A/C on
> high and idle the engine at about 1500-2000 RPM, and the temperature
> readings should drop. The outlet temp will be higher than the inlet if the
> system is undercharged. Open the R-134A can's valve slightly to SLOWLY
> charge the system until the outlet temp is almost as cold as the inlet
> temp, or the pressure readings are right, whichever comes first. Try to
> charge while the outdoor temp. is around 70F - 80F because in hotter
> weather you need to undercharge the system to prevent excessive pressure.
> Before connecting the hose to the low-side charging port, open the R-134A
> can's valve slightly, to purge the air out of the system, and don't close
> the valve until hose fitting is attached.


......

Thanks to everyone for the advice. This is embarrassing, but I think
the A/C is working properly. I didn't realize that for the REAR AC to
work, the FRONT AC button has to be on. I thought that if the rear
knob was pointing at the blue AC button, that should activate the rear
AC. But I didn't realize the rear AC shares refrigerant with the
front AC until I started researching the "problem".

When the front AC is on, the rear blows noticeably colder. I'll do a
temperature check with my thermocouple next time I get a chance, but,
yeah.

Thanks!

Michael

+++++++++++++++++++++++++++++
Yes, for the rear to work, the front has to be on.




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Old 03 Jun 2012, 07:48 pm   #18 (permalink)
Daniel who wants to know
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Default Re: adding R134a to a 2002 Sienna

"Michael" <mrdarrett@gmail.com> wrote in message
news:f95a3ab9-43a3-46ba-9e09-d9c02048c6bf@nl1g2000pbc.googlegroups.com...
>I have the exact same problem as this guy, and I'm wondering if the
> solution is the same.
>
> http://www.toyotafans.net/2004-sienn...cold-t4400.htm
>
> I've seen cans of R134a at the store, and I'm wondering how difficult
> this is to do. What are the specs on the minimum pressure at the low-
> side charging port? This doesn't seem to be specified in the Haynes
> manual I've got.


As mentioned, a refrigerant's temperature and pressure are directly related.
Pure propane (R-290) is always 0 PSIG at -44 F, R-134a is always 0 PSIG
at -15 F

R-134a is always 28 PSIG at 32 F, hence you want the low side pressure as
close to 28 PSI without going under.

> I'm guessing I should get a can of R134a that has a pressure gauge, so
> I'll know how much refrigerant I need to add... if any.


The cheap gauge that the cans have tell you nothing, cars are charged by
weight of refrigerant from a vacuum. Attempting to "top off" a partially
charged system is always a guessing game.

This is especially true on vehicles like mine which have a variable
displacement compressor, these regulate the low side pressure without
cycling so it will always be at the set point all the way from having less
than an ounce of liquid refrigerant up to being slightly overcharged, making
that gauge meaningless.

>
> Also, where exactly is the low-side charging port? Again, the Haynes
> manual isn't very clear about *where* it is.
>
> Thanks,
>
> Michael


Barring a weight/mass charge spec then a fixed orifice system is charged by
suction superheat, this is what "larrymoencurly" is measuring with the 2
thermometers, but it is more accurate to use the temp scale on a good
pressure gauge along with the thermometer on the evap outlet. IE if the
gauge says the refrigerant is boiling at 32 F in the evaporator and the
thermometer on the suction line reads 42 you have 10 of superheat. Some
positive superheat is required to know for sure that no liquid is making it
back to the compressor inlet, but too much superheat means that only part of
the evaporator is evaporating refrigerant, and you want as much of it in use
as possible for the coldest vent temperatures and best dehumidifying.
Suction accumulators help to keep liquid from getting to the compressor.

Expansion valve (TXV/TEV) systems are charged by liquid subcooling because
the valve controls the suction superheat automatically, this requires a high
side gauge with a temp scale and a thermometer on the liquid line. Once
again if the gauge says that the refrigerant is condensing at 100 but the
liquid line is only 80 you have 20 Positive subcooling is required
because vapor bubbles in the liquid to the expansion valve impair its
function, but once again too much subcooling means that the liquid is
backing up into the condenser and reducing its effective size. Liquid
receivers help to keep a solid column of liquid (no vapor) to the expansion
valves. This is also the reason for the sight glass, to let you know if
there are bubbles in the liquid.

Luckily with cars subcooling and superheat will be correct if you charge an
empty functioning stock system by weight to spec.


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Old 03 Jun 2012, 11:33 pm   #19 (permalink)
uncle_vito
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Default Re: adding R134a to a 2002 Sienna


"Daniel who wants to know" <me@here.edu> wrote in message
news:jqgt3q$f6j$1@dont-email.me...
> "Michael" <mrdarrett@gmail.com> wrote in message
> news:f95a3ab9-43a3-46ba-9e09-d9c02048c6bf@nl1g2000pbc.googlegroups.com...
>>I have the exact same problem as this guy, and I'm wondering if the
>> solution is the same.
>>
>> http://www.toyotafans.net/2004-sienn...cold-t4400.htm
>>
>> I've seen cans of R134a at the store, and I'm wondering how difficult
>> this is to do. What are the specs on the minimum pressure at the low-
>> side charging port? This doesn't seem to be specified in the Haynes
>> manual I've got.

>
> As mentioned, a refrigerant's temperature and pressure are directly
> related. Pure propane (R-290) is always 0 PSIG at -44 F, R-134a is always
> 0 PSIG at -15 F
>
> R-134a is always 28 PSIG at 32 F, hence you want the low side pressure as
> close to 28 PSI without going under.
>
>> I'm guessing I should get a can of R134a that has a pressure gauge, so
>> I'll know how much refrigerant I need to add... if any.

>
> The cheap gauge that the cans have tell you nothing, cars are charged by
> weight of refrigerant from a vacuum. Attempting to "top off" a partially
> charged system is always a guessing game.
>
> This is especially true on vehicles like mine which have a variable
> displacement compressor, these regulate the low side pressure without
> cycling so it will always be at the set point all the way from having less
> than an ounce of liquid refrigerant up to being slightly overcharged,
> making that gauge meaningless.
>
>>
>> Also, where exactly is the low-side charging port? Again, the Haynes
>> manual isn't very clear about *where* it is.
>>
>> Thanks,
>>
>> Michael

>
> Barring a weight/mass charge spec then a fixed orifice system is charged
> by suction superheat, this is what "larrymoencurly" is measuring with the
> 2 thermometers, but it is more accurate to use the temp scale on a good
> pressure gauge along with the thermometer on the evap outlet. IE if the
> gauge says the refrigerant is boiling at 32 F in the evaporator and the
> thermometer on the suction line reads 42 you have 10 of superheat. Some
> positive superheat is required to know for sure that no liquid is making
> it back to the compressor inlet, but too much superheat means that only
> part of the evaporator is evaporating refrigerant, and you want as much of
> it in use as possible for the coldest vent temperatures and best
> dehumidifying. Suction accumulators help to keep liquid from getting to
> the compressor.
>
> Expansion valve (TXV/TEV) systems are charged by liquid subcooling because
> the valve controls the suction superheat automatically, this requires a
> high side gauge with a temp scale and a thermometer on the liquid line.
> Once again if the gauge says that the refrigerant is condensing at 100
> but the liquid line is only 80 you have 20 Positive subcooling is
> required because vapor bubbles in the liquid to the expansion valve impair
> its function, but once again too much subcooling means that the liquid is
> backing up into the condenser and reducing its effective size. Liquid
> receivers help to keep a solid column of liquid (no vapor) to the
> expansion valves. This is also the reason for the sight glass, to let you
> know if there are bubbles in the liquid.
>
> Luckily with cars subcooling and superheat will be correct if you charge
> an empty functioning stock system by weight to spec.
>


I am impressed with your knowledge. Is variable displacement fairly common
in cars today. I own Toyotas. Is that what they use. I have noticed no
cycling. I have noticed also that A/C systems seem to last the life of the
cars. The old GM systems from the 70-80's used to crap out or burn up a
clutch seemingly all the time.


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Old 04 Jun 2012, 11:43 am   #20 (permalink)
Michael
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Default Re: adding R134a to a 2002 Sienna

On May 27, 8:05*am, "Jeff Strickland" <crwlrj...@yahoo.com> wrote:

....

> Thanks to everyone for the advice. *This is embarrassing, but I think
> the A/C is working properly. *I didn't realize that for the REAR AC to
> work, the FRONT AC button has to be on. *I thought that if the rear
> knob was pointing at the blue AC button, that should activate the rear
> AC. *But I didn't realize the rear AC shares refrigerant with the
> front AC until I started researching the "problem".
>
> When the front AC is on, the rear blows noticeably colder. *I'll do a
> temperature check with my thermocouple next time I get a chance, but,
> yeah.
>
> Thanks!
>
> Michael
>
> +++++++++++++++++++++++++++++
> Yes, for the rear to work, the front has to be on.



And, yeah, I finally got my thermocouple out and the rear is working
quite well.

I measured bet. 80 and 85 degrees with just the blower on, then when
the AC started, it dropped to around 60 or so... then as we drove some
more, I gave the thermocouple to the kids, who said the lowest
temperature they got was 30 degrees (?!!) I still can't believe that,
but it sure feels cold so it's good enough for me.

Thanks everyone!

Michael
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