Toyota Corolla 1984 - R12 system troubleshooting

[syncview]

I recently worked on a toyota corolla 1984

it has an R12 system

items installed brand new:
1 - compressor
2 - serpentine condenser
3 - DENSO TXV
4 - new suction, discharge and liquid lines.
5 - receiver drier

added in around 760-780g of R12 refrigerant and suniso 4gs oil 240ml - as per factory specs.


The system works nicely when the ambient temperature is around 30c or 94F with temps below 10c or 50F all the time.

problems start when ambient temps to go above 40C or 100F, i couldn't get the data in such ambient temps because whenever I got the car, weather seemed to be friendly.
it doesn't seem to cool down the cabin to a comfortable temp under 100F+ heat, it kinda makes the cabin humid too - the system is not dehumidifying (if i can say that)

here is the data anyway - blower to MAX

at 1500RPM - ~15mins running

ambient temp: 95F
SUCTION: 30psi
suction line temp: 38F
superheat: 6F

head pressure: 155psi
liquid line temp: 101F
subcool: 18F

~30mins running:

ambient temp: 95F
SUCTION: 26psi
suction line temp: 53F
superheat: 26.1F

head pressure: 160psi
liquid line temp: 100F
subcool: 21.2F

~45mins running:

ambient temp: 95F
SUCTION: 32psi
suction line temp: 51F
superheat: 16.6F

head pressure: 170psi
liquid line temp: 105F
subcool: 20.6F

~60min running:

ambient temp: 95F
SUCTION: 26psi
suction line temp: 53F
superheat: 26.1F

head pressure: 165psi
liquid line temp: 106F
subcool: 17.4F

other things to note:
the evap housing and vent ducts get wet after 30mins of running
suction line is sweaty throughout from the evap to compressor
touching the compressor body, it doesn't seem like its being flooded by liquid refrigerant


please, any suggestions are appreciated.

[xxargs]

26 PSI = 1.8 Bar (2.8 Bar absolute) and give boil temperature for R12 of ~ -3 degree C or 26.6 F

ie. high risk your evaporator icing/frozen

Check/adjust some thermostat/sensors on evaporator so it pull of compressor if evaporator going below icing temperature more than very short time per compressor running cycle, ie. should not going below 29 PSI more than very short time (few or ten seconds) before compressor stops.

[syncview]

I set the tstat to trip the compressor when vent temps gets to 44F

does it look like I need to add more refrigerant?

[charlie patt]

The English capacity was 908 grms but that's uk spec but these originally had a sight glass did yours ? My concern is lack of head with your ambient in uk that would be hitting 200 psi even with fan full chat if unit was freezing up suction line would be freezing up is it? And excuse my ignorance is it good 12. ?

[syncview]

umm.. thats interesting, because i just confirmed from the owner that it is indeed a UK import. so for now I'm running low on refrigerant

and, suction line is not freezing, its all sweaty

yes, the 12 is good. have a full cylinder of it - Genetron R12

yes, there is a sight glass - I'm just not experience enough with a sight glass and R12 to use it..
I do understand that the sight glass has to be clear of any bubbles but its the peculiar details I lack :)

[hyperion]

Gradually put another 120 grams in. Check the sight glass until it is clear.
The UK spec system may not have been totally suitable for the higher ambients, so be careful when charging it. Do not overcharge.
The head pressure will go up considerably,so be careful.
As Charlie mentioned, the head pressure could easily go up to 200psig.

[charlie patt]

Uk spec car in 40 dc ??the official spec from Toyota was clear sight glass and count to ten charging on a vapour on idle then shut gauges down also if uk spec car does warmer countries have better insulation to allow for the extra heat? I would run system and charge till clear glass then as spec count to ten and shut of the gauges then sea what it does then if uk spec car it's built for a max of 29?dc and bloody high humidity not 40 u may have a unit that is working its beans of, when we import ac kits from Italy big evaps big comps fan speed control but when they where made in UK small evap next size down comp fixed condensor as duty not required

[syncview]

I added more refrigerant, using the sight glass
now at 90F ambient, i'm looking at 33-35psi suction, 200-225psi head pressure. vent temps were between 44-48F. fingers crossed, lets see how it behaves in 100+.

yeah, UK spec vehicle may not be able to cope up with the heat here but i've been in other vehicles of the same kind.. they do make the cabin at least comfortable to sit in. Although the PK spec corolla of the same era would freeze the nuts.

[charlie patt]

I did check with our car wholesaler today UK spec Corolla five loop evap lhd version nine loop! There is your performance difference

[syncview]

Yep that it indeed has a five loop evap

but its working really nice now - enough for the customer to be satisfied