R134 conversion
03-27-2017, 01:18 PM
#16
Because my understanding was that you have oil that pools in various components and you can't get it all out unless you pull every component. I think the majority is in the compressor so you change that out and put in the new oil and hope for the best (because changing every component is not feasible).
03-27-2017, 06:49 PM
#17
Rennlist Member
As you surmise, pulling a vacuum does nothing to the oil.
03-27-2017, 10:29 PM
#18
Rennlist Member
Thread Starter
A lot of good info here, I'm going to order an o-ring set, and I've been advised to get a "drier canister" as well.
I'll tear the whole system down, clean, reseal, and vacuum/charge the system.
As soon as I get time for my own car, there are a few in line now (I wish family members would buy cars with warranties)
Thanks Guys!
Greg
I'll tear the whole system down, clean, reseal, and vacuum/charge the system.
As soon as I get time for my own car, there are a few in line now (I wish family members would buy cars with warranties)
Thanks Guys!
Greg
03-28-2017, 10:35 AM
#19
simple answer for R134 conversion:
-- replace all the O-rings in the system
-- drain compressor of as much oil as you can, find new oil that is compatible with R12 and R134 (name escapes me currently)
-- remove condenser from the car and backflush with mineral spirits or other suitable solvent and compressed air to push **** out and dry the inside...let it sit in the sun for a while to warm up and let any residual MS out
-- comb fins of condenser clean of birds and rocks and leaves and make them straight again - this will make a huge difference in efficiency
-- remove the high/low side R12 scrader valves and fit the new R134 adapter fittings with new valves
---- if you have an early car you need to get a 90-degree adapter fitting for the low side that mounts on the compressor, to clear the alternator bracket
-- pull a vacuum as far down as you can on the system to check for leaks - i have a monster pump that goes to -30 inches. leave it under vacuum for a few hours and occasionally check the gauge reading to make sure it isn't leaking
-- when you go to fill the system, leave it under vacuum. start the car and let it run, hook up your r134 can to your gauge set and shake the can a bit, open the valve and the vacuum in the system will help to draw in the first bit of freon. activate the AC switch and fan to max and just shake the hell out of the r134 can to get the gas flowing, eventually the compressor clutch will activate and begin pulling freon from the can on its own.
-- R134 fill capacity is about 75-80% of the R12 amount written on the sticker on your fender.
-- TYPICAL fill pressure i have seen on 944 (with the compressor running) is 30-40psi low side, 140-150psi high side. depending on ambient temperature and your individual system it may vary a good bit.
-- replace all the O-rings in the system
-- drain compressor of as much oil as you can, find new oil that is compatible with R12 and R134 (name escapes me currently)
-- remove condenser from the car and backflush with mineral spirits or other suitable solvent and compressed air to push **** out and dry the inside...let it sit in the sun for a while to warm up and let any residual MS out
-- comb fins of condenser clean of birds and rocks and leaves and make them straight again - this will make a huge difference in efficiency
-- remove the high/low side R12 scrader valves and fit the new R134 adapter fittings with new valves
---- if you have an early car you need to get a 90-degree adapter fitting for the low side that mounts on the compressor, to clear the alternator bracket
-- pull a vacuum as far down as you can on the system to check for leaks - i have a monster pump that goes to -30 inches. leave it under vacuum for a few hours and occasionally check the gauge reading to make sure it isn't leaking
-- when you go to fill the system, leave it under vacuum. start the car and let it run, hook up your r134 can to your gauge set and shake the can a bit, open the valve and the vacuum in the system will help to draw in the first bit of freon. activate the AC switch and fan to max and just shake the hell out of the r134 can to get the gas flowing, eventually the compressor clutch will activate and begin pulling freon from the can on its own.
-- R134 fill capacity is about 75-80% of the R12 amount written on the sticker on your fender.
-- TYPICAL fill pressure i have seen on 944 (with the compressor running) is 30-40psi low side, 140-150psi high side. depending on ambient temperature and your individual system it may vary a good bit.
03-28-2017, 12:02 PM
#20
Rainman
Rennlist Member
Rennlist Member
Yes...let drain out as much as you can, then just refill the correct amount for your compressor...
early cars use a Nippondenso 6E171 compressor, late cars use a 10P15 style.
If you google those numbers and "oil capacity" you'll find charts.
early cars use a Nippondenso 6E171 compressor, late cars use a 10P15 style.
If you google those numbers and "oil capacity" you'll find charts.
03-28-2017, 02:49 PM
#21
Addict
Rennlist Member
Rennlist Member
Driers are $10, good thing to change. There is a spec for how much oil to add to the drier.
It's supposed to be good to replace the valve cores also however I had leaks after replacing mine, I am not sure if the replacements were of poor quality or if I need to clean out the sealing surface they screw into.
It's supposed to be good to replace the valve cores also however I had leaks after replacing mine, I am not sure if the replacements were of poor quality or if I need to clean out the sealing surface they screw into.
03-28-2017, 03:00 PM
#22
Rainman
Rennlist Member
Rennlist Member
^^Never added oil to the driers - I just uncap them and install them as quick as possible to preserve the dessicant..lol
They'll get oil from circulation eventually.
They'll get oil from circulation eventually.
03-28-2017, 03:15 PM
#23
Rennlist Member
And a drier is just a canister of desiccant - like the little silica packets you're not supposed to eat when you order stuff on line. There are no moving parts in a drier, so it doesn't need oil/lubrication.
03-28-2017, 03:44 PM
#25
Addict
Rennlist Member
Rennlist Member
The silica gel packs have a nice minty taste.
I thought there was a spec to add some oil to the drier to replace what is in there when you toss out the old one. It's a pretty small amount.
I thought there was a spec to add some oil to the drier to replace what is in there when you toss out the old one. It's a pretty small amount.
