Vx Commodore Air conditioner Diagnosis

[@ianmcculloch8531]

So some simple fixes like these could be used to pull the wool over a customers eyes. Thanks for the information.

[@lynpatnat]

@@ianmcculloch8531 There is always that risk. If you can't get a friend to recommend someone for repairs that's the best option. A little bit of understanding can give you enough information to decide if you need to drop money on a repair. They have a big problem with leaking out of the high and low connection ports. Aluminium housing for a metal valve was never a good design.

[@matthewjones8865]

Yes very helpful and interesting seeing how things operate on vehicle’s. Thanks very much.

[@lindonwatson5402]

clear, concise and well presented. thank you

[@lynpatnat]

Thanks. I hope it helps.

[@karlosss1868]

Very helpful. Many thanks!

[@Damian-Church-NZ]

Thanks dude you're a genius 🙏

[@lynpatnat]

Thank you. I am so glad I could empower you to be able to check your own car. That's the goal.

[@feralpanda5084]

Do you know if the service port can be unscrewed from above the pressure switch? My schrader valve is leaking but it seems that the service port needs to be removed to get the valve out. This is for a VU SS

[@lynpatnat]

@@feralpanda5084 you can unscrew the pressure switch straight out of the pipe. There is a Schrader valve behind it. I'm assuming it is the same in all this era of Commodore. It has one on the one ones I've tried. If it leaking you will have to replace it anyway so you may as well try. Other brands of cars may not have the valve behind but definitely the vx does and the vy probably does.

[@lynpatnat]

The service port itself cant be removed but the valve can. Unfortunately this a big problem area. They all leak. I've tried changing the valve but they always leak. Maybe is you tigened it slightly you could get lucky but I never have found there is a any solution. Shit design i think. The schrader valve just uncrews. Use a normal car air valve tool. You will lose the gas so it should be done professionally unless its already empty. The thread inside is 8mm find metric.

[@jimcheers4341]

Wikid vid mate, thankyou. Perfect. If there's a way to do the regassing easy enough then let us know cheers.

[@lynpatnat]

The high and low side valves leak on commodores. Bad design in aluminium. I've even had the rubber pipes become porous. If you look up hychil you can b get an idea if he to recharge. Technically it's a mix of hydrocarbons. Similar but not quite the same as LPG. LPG pressure will be a bit high and it week also be a bit b cold so be will freeze in the evaporator. Look up data sheets for hychil 30.

[@lynpatnat]

Also from memory the low side inside thread is m8. You can use a lock but on a bolt. Put a great if thread tape on the bolt. Screw it in about 10mm and lock down the lock nut. This week slow down the leak but probably went stop it. Plus the barb connection will flare so it hard to get the fittings on and you may have to use emery paper too make the small enough to regas it the next time. You may also be able to snug the valve down but I've had them go to shit and end up so deep in the fitting that you can't get gas in without backing them out again. Using aluminium for the pipes was such a crap idea. Maybe sooner can make new pipes. Thats singing something I've never looked into but it would solve half the issues. Our old car is making some death rattle lifter noise presently. I'm sitting on the fence as to weather it's worth the time and effort to fix. 509000 km. It's been a great car but nothing can run forever.

[@jimcheers4341]

Thanks for the detailed info mate! I'll have a good suss sometime soon and let u know what I find. They do refrigerant cans with the guages on them so might be buying one soon if clutch is working, seems as tho she jus has no gas

[@lynpatnat]

@@jimcheers4341 I am not sure of that gas. I think it's called r1234. That says it's not compatible but I bet it is. It's expensive at about $100 a can. You may find that if you pole at the valve and no gas comes out and you use a valve tool to make the high and low pressure valve are tight then maybe get a mobile guy out to give it a vac and regas. They should use a sniffer (about $1000 to buy) and then sort it out. They may want to replace the receiver dryer too but you can chance but doing that if you don't plan to keep the car for 10 more years. Micro leaks are buggers to find. Best of luck.

[@jimcheers4341]

Ok, thanks again for the info and advice good sir , my mate at work has done his commo in recent yrs so it's doable an jus got the gas from Supercheap he said, take care

[@bazzad4807]

Placed the AC relay in the Horn relay slot {VT} and the horn still worked, noticed tho, the Horn relay is 5 pin, AC is 4 Pin. Refitted AC still does not engage- Start car, AC turned on, light glows at switch, checked Fans, removed Temp Sensor Plug, fans engaged all OK-AC still not engaged. Removed Low Pressure Switch Plug, fans engaged after a few seconds {Both} still no AC engagement. concluded, relay OK, Fans OK, still not sure about gas levels,Will check AC circuit continuity and if OK, Technician time. will need regas and leak check.

[@lynpatnat]

You could make some jumper pins and power the AC clutch directly. It's very fiddly to work down there though or you can jump the two slots that the relay bridges when activating. You can work which pins that are by looking at the relay diagram on the side if the relay. Or popping the cover off the relay and looking at how it works. If the gas is low then the computer may prevent it running. I'm not sure if it's wired that way but it may be. Other than that a bit of gas in the system will tell you if it's more gas. Regassing sounds like the easy path as you have given it good look over and eliminated most possible things.

[@lirwin89]

Any way to diagnose whether the pressure switch is good or not without adding or removing gas?

[@lynpatnat]

I don't think it would be easy as from memory there are 3 wires. That would mean the computer monitors it. If you had a oscilloscope you would be able to probe for the pulses maybe. Its not my field. I would say though if everything else has checked out and you still are not getting the clutch to cut in then it will be the pressure switch. They have valve behind them so you can remove(unscrew) the valve and it won't lose gas. You could then poke that valve with a screwdriver to see if there is any gas in the system. These cars have aluminium pipes and valve seating areas. They are so prone to leaking gas past the seats. A short 5/16 bolt with a nut about 10mm up the thread and a great of thread tape will help seal it a bit better but don't tighten it into the base of the thread to hard it you will cause the aluminium to expand and then cant get the charge hose connectors to fit. I also suspect that these cars get pinholes leaks in the rubber pipes but they are so small you can't find them. I had a hose delaminate and bulge before I found the leak. There is a gas that is suitable and commercially available that is a mix of propane and butane. Google it and I think it's sold on eBay too. It is a direct replacement for r134. Its better for the environment too. I don't think they recommend to blend it with r134 though but as far as I know you can refill with it without a full flush.

[@lynpatnat]

If you want an insight search on KZbin for "using propane instead of R12". This is of course just for information. I would not suggest putting a small amount in to see if the clutch then engages and certainly don't fill the low side to the point that the TX valve at the firewall starts to go cold when the car is running. Just as a test to decide. Gas is very flammable and with an engine running it could be very dangerous. Many people don't realise that R12 and r134 under pressure in a system and with the oil in the system is also extremely flammable. The gas produced when they burn is toxic. R12 burning is mustard gas. Thats like WW1 in the trenches. In the early days we tested for leaks in the system with a special tool that had a flame. When the flame went yellow there was a leak. (Uhhh... Palm smacks on forehead) LPG burning is just a big fire... Very big fire. Take care read so you get knowledge but don't take risks.