How long will 134a stay in a R12 system?
07-30-2016, 01:26 PM
#16
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07-30-2016, 08:24 PM
#17
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If you have a gauge set, Walmart now sells R-134a for $4.50/12 oz can. You can top off for less than $10/year, Takes ten minutes. Harbor Freight sells the gauge sets.
07-30-2016, 08:40 PM
#18
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Acutally, I have never converted either of my R12 cars to R134 because of the "why-change-something-that-is-mostly-working" approach. The question for some 928 owners in the future may become, "What does it take to convert an R134 system back to R12?" I am thinking you would have to change a lot of parts to get the other lubrication out.
07-31-2016, 12:07 AM
#19
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... I ready through the DYI O ring conversion https://rennlist.com/forums/attachmen...placement1.pdf and it looks straight forward, and time intensive. So maybe this gets added to the winter projects list.
"site:rennlist.com inurl:928 ac oring replacement" and
"site:rennlist.com inurl:928 ac o'ring replacement"
And got a lotto stuff.
https://rennlist.com/forums/928-foru...placement.html
From Bilal, in 2013: "AC O-ring replacement" w/ lotso pix
Part 1a: https://rennlist.com/forums/attachme...lacement1a.pdf
Part 1b: https://rennlist.com/forums/attachme...lacement1b.pdf
https://rennlist.com/forums/928-foru...ml#post9670123
From Nichols Tip #736 http://www.nichols.nu/tip736.htm
(I don't see the 900.174.011.40 one listed, though):
From Bilal, in 2013: "AC O-ring replacement" w/ lotso pix
Part 1a: https://rennlist.com/forums/attachme...lacement1a.pdf
Part 1b: https://rennlist.com/forums/attachme...lacement1b.pdf
https://rennlist.com/forums/928-foru...ml#post9670123
From Nichols Tip #736 http://www.nichols.nu/tip736.htm
(I don't see the 900.174.011.40 one listed, though):
Quote: Originally Posted by Nichols Tip #736
part number; size(mm); # front; # rear
==============================
999 707 284 40; 6.6 x 1.5; 0; 2
999 707 247 40; 7.5 x 2; 4; 3
999 707 261 40; 9.0 x 1.8; 2; 0
999 707 250 40; 10.6 x 2; 3; 1
999 707 251 40; 14.0 x 2; 3; 4
999 707 252 40; 17.0 x 2; 2; 0
And here's where they're all located:
Front A/C:
expansion valve (under plastic tray next to intensive washer reservoir): 2 x #251, 1 x #250, 1 x #247.
return line from expansion valve, middle of firewall: 1 x #252.
compressor fittings: 1 x #251, 1 x #250.
other side of return line to compressor at low side fill valve: 1 x #252.
heading into condenser: 1 x #250.
bottom of condenser heading up to receiver/drier: 1 x #247.
pressure and temperature switches just before receiver/drier: 2 x #261.
at receiver/drier: 2 x #247.
Rear A/C:
expansion valve: 2 x #251, 1 x #250, 1 x #247.
solenoid valve under passenger seat: 2 x #284.
2 pipes under car from solenoid valve to front connections: 2 x #251. 2 x #247.
FWIW, I remember getting a big assortment from a local auto parts place (probably NAPA) a few years ago that was labeled for use in some Nissan model (IIRC; I've lent those out right now and can't check); there was quite a bit of overlap with the above sizes.
part number; size(mm); # front; # rear
==============================
999 707 284 40; 6.6 x 1.5; 0; 2
999 707 247 40; 7.5 x 2; 4; 3
999 707 261 40; 9.0 x 1.8; 2; 0
999 707 250 40; 10.6 x 2; 3; 1
999 707 251 40; 14.0 x 2; 3; 4
999 707 252 40; 17.0 x 2; 2; 0
And here's where they're all located:
Front A/C:
expansion valve (under plastic tray next to intensive washer reservoir): 2 x #251, 1 x #250, 1 x #247.
return line from expansion valve, middle of firewall: 1 x #252.
compressor fittings: 1 x #251, 1 x #250.
other side of return line to compressor at low side fill valve: 1 x #252.
heading into condenser: 1 x #250.
bottom of condenser heading up to receiver/drier: 1 x #247.
pressure and temperature switches just before receiver/drier: 2 x #261.
at receiver/drier: 2 x #247.
Rear A/C:
expansion valve: 2 x #251, 1 x #250, 1 x #247.
solenoid valve under passenger seat: 2 x #284.
2 pipes under car from solenoid valve to front connections: 2 x #251. 2 x #247.
FWIW, I remember getting a big assortment from a local auto parts place (probably NAPA) a few years ago that was labeled for use in some Nissan model (IIRC; I've lent those out right now and can't check); there was quite a bit of overlap with the above sizes.
07-31-2016, 04:37 AM
#20
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High Side/Low Side Pressures
Anyone know what the high side/low side pressures should be on a correctly charged system? That would be nice info to have when refilling.
I bought my gauge set on Amazon, I am very happy with it. Harbor Freight sells good inexpensive sets also.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Here is an informative video on using a gauge set.
I bought my gauge set on Amazon, I am very happy with it. Harbor Freight sells good inexpensive sets also.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Here is an informative video on using a gauge set.
07-31-2016, 10:11 AM
#22
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Lots of variables, but the low side should be 30-35 psig @1500 rpm and good air flow over the condenser. High side will be determined by ambient temp, air flow over the condenser, system conditions, amount of non-condensables, etc., etc., but usually somewhere between 200 - 300 psig.
07-31-2016, 11:18 AM
#23
Rennlist Member
This chart is an approximate guide. If you are starting with an empty system be sure to pay close attention to how much refrigerant is going in. Overfilling will kill your compressor.
07-31-2016, 12:02 PM
#24
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