Hi All,

I have had some fun with my aircon unit since i had work done to it

backgound

Xj6 1984 SIII ,Car went to malaysia to get restored "body work" however evaporator was checked out and refitted and heater core replaced car has since been shipped back

The problem

1 i live in Australia..
2 Poor cooling pushing out air around 30 deg from the vent stationary
aircon basically sucks *****
3 spending lots of money trying to fix it but not getting anywhere

to give you a breakdown on whats been done

checked and refitted evaporator performed overseas "Malaysia"
replaced leaking heater core "Malaysia"
replaced 134a compressor twice in one month "Australia"
Replaced Expansion valve "Australia"
replaced Drier "Australia"
Delanair checked out and working properly "no mixing of hot from core"
Condenser has been there for as long as i can tell

now my jag dealer who will remain nameless...cause they are pretty good guys and i think this has been a bugger of a job.

but i got an aircon guy out that i have used before to check over the system

it currently has superchill 0S12a when he hooked his gear up he said immediately that the pressure was way to high on the high side he kinda felt that i had around 200ml of oil running in the system, he also didnt have good things to say about the OS12a gas said that its not good and tends to eat at aluminum components

he advised a flush as he believes that the oil is constricting the flow of gas to the evaporator

he removed a good portion of the gas and put 134a and the temps dropped fro 30deg c down to 23 deg c stationary and i reckon its cooler when i drive...but its no winter holiday in 34 degree heat but was complaining bitterly about the amount of oil on present

any thoughts on this OS12a gas and has anybody gone through similar madness


ps love the emotes

 

hi,
mixing refrigerants is never a good idea, whether compatible or not; it should be one or the other, and everytime you change refrigerant, the a/c system should be flushed and any remaining oil and humidity removed with a vacuum pump, then allowed to sit for at least 1 hour to check for any leaks.

R134a does not cool as good as R12 when used in older car a/c systems designed for R12, that's a proven fact. I am not familiar with the other refrigerant you mention so I cannot comment on it.

R12 is still being manufactured in Brazil and Mexico by DUPONT, it is only in the US that it is no longer sold, but it is still available because government fleets and commercial fleets still use R12, so the whole thing is one big hipocresy. If you search enough, you will find R12 in AU to re-do your system.

it also sounds as if your system is working, just not cold enough, so I would follow the technician's advice and start from scratch by removing all the oil and refrigerant and recharging the system properly.

 

Hi Jose ...oh to not be in a nanny state,

Yes Clearly R12 would be the best option but was outlawed in the early 90s and we all ad to eventually convert over to r134a, and i must admit its been fine on the new gas, but now they have deemed 134a evenworse enviromentally than r12, this OS2a or an organic thing from what i know, the tech wanted to test his theory about the gas which has helped cleared things up a little, but i will be hoping to flush it out this thursday comming,

strangley enough i have seen no posts on any forum about this gas, i hoping to get a positive result and perhaps somthing to consider for any memebers being pushed into this path

 

it's one of those "Alternative Refrigerants", there are many alternative refrigerants now-a-days, approved for use in cars. Another is called "Freeze 12" and it is a mix of R134a and R22, (R22 is used in residential a/c),

 

Manage to find somthing on it soiwill dosomemore research and post back

OS-12a is a blend of purified R600a and R290, these are two natural hyrdrocarbon refrigerant gases. The
blend of OS-12a has been specifically designed for the Automotive, Transport, Mining and Agriculture

airconditioning systems as a complete drop in replacement for CFC-12 and HFC-134a

 

Very High pressures on the high side is usually an indication of a clogged expantion valve. The oriface tube may have gotten clogged with some debris which is likely because the system may have been open from the recent heater core replacement. I'd install a new expansion valve and while the system was apart remove and flush the lines and compressor. Then install a new reciever drier, vaccum down for 30min, oil up and test for leaks, Be sure to change the orings to the green type while you're there. I've used various "drop in" replacement refrigerants but some are flamable so I stick with R134.

 

Yeah he did indicate that but he was shocked with the amount of oil when draining the unit on the low side ...i think and i knew he was being naughty by doing that as he removed some of the gas it did get cooler

do i still need to replace these again "Then install a new reciever drier "it was only done a month ago :/

is the expansion vavle interchangeable from the engine bay or is one peice with the evaporator ?

 

replacing the expansion valve is a very delicate procedure, two large wrenches are needed, one to hold the valve body in situ, while another loosens the nut. Leave it to the technician. The valve itself is a General Motors/Delco design used in many cars under many different brands like 4-Seasons, Coolaire, and who knows what else. It is an old design but a lot better than modern orifice-tube systems.

Another thing: is your expansion valve covered with a gooey tar-like insulation material? or is it uncovered? The gooey stuff helps the cooling of the cabin, it keeps the expansion valve cool, the location behind the engine doesn't help cooling. Make sure you wrap it with that stuff.

 

Did some more indepth testing with some help here what we found

"S6" Compressor.... Seems to be Replacement for GM A6.
However the Car apparently had a Harrison on there at some Point before.


2 S6's failed had Previous Compressor Failures in Short time 1 month. We do not know if previous shops have hoping to confirm if workshop had the System of Oil, replacement compressors were also oil filled. Suspicion is too much oil in system
now.

Has New Compressor, New Drier, New TXV Which is mounted in the Engine bay, Wh
The Probe that touches the Suction line is Insulated though.



Readings, Pressures, Temperatures :


Ambient Temperature - 37 Degrees Celcius (99F)
Humidity - 10%

Fresh Mode (Car has no Recycle Mode)

500/600RPM Idle

Lo - 55
Hi - 308 slowly rising - Hitting High Pressure cut-out at around 315 or so
Liquid Line - Scortching Hot
Vent - 28C (82F)

Sprayed Condenser with Water Spray bottle as much as I could for a decent time :

Lo - 50
Hi - 270
Vent - 21C (70F)

Raised Idle to 1000 RPM With no Water Spray, it was rapidly cycling off the high pressure switch before we could get stable readings.
With Spray :

Lo - 40-43
hi - 270
vent - 21C (70F)

1500RPM - NO Water Spray to condenser

Lo - 38
Hi - 300 and then Cutting out Very often.

1500 RPM - With Water Spray

Lo - 24 - Weird, Unnussually Low?
Hi - 250
Vent - 20C (68F)


after he removed the guages.... Also Oil was dribbling out of the hoses Somewhat Chronic afterward kinda reinforces the too much oil scenario