2009 VE SV6 Aircon problems and questions

[Anthony .]

Hi all,
I have a few questions about the aircon system in my VE SV6. Please bear in mind, given how cold it has been in Melbourne I have been using the heater quite often (it is frequently used).

Let me paint a picture first.

. No cold air, only the blower only spins when put on cold, but hot is great.

. The AC button on the temp dial does not illuminate at all/ when pressed. Could this maybe be a fuse that is causing the ac system not to work?

Today, started the car and put the heater on (which was previously left on the “leg setting” for lack of a better word) and the fan/ blower sounded like it was knocking/ binding on something. So I flicked through the other climate settings (I.e front defroster, etc. and still made that sound until 30 secs later but back to normal. BUT now the “leg setting” does not work.

Please bear in mind that I replaced the cabin filter 6000km ago, and the engine bay is clean (no leaves, shrubs, etc) and the car is not parked under a tree for that to happen.

Apologies for the essay/ word vomit but I would appreciate to hear some opinions and advice.

Thanks,
Anthony

 

[Skylarking]

Here’s a simplified generic rundown of an ac system…

[TLDR]
Take it to an ac specialist so they can check the system has gas.

[The Long Story]
Some commodores used a variable vane compressor (which may or may not have incorporated a clutch pulley arrangement) while others had an older style fixed ratio compressor with a clutch pulley to engage the compressor. The system also has high and low pressure sensors within the ac lines and logic within some module that controlled the whole apparatus.

To turn on your ac, you’d press the ac button which causes stuff to automagically happen and if all is ok yje lamp goes on. Before the ac system can actually operate, system logic would check to ensure that there is enough gas within the ac lines using the low pressure switch. If pressure is ok, it would turn on the ac compressor by either adjusting the variable vane (PWM signal) and/or switching on the clutch pulley (+12v) depending on the hardware in your car.. Then the ac compressor will be spun by the engine and it can then do its job which will see the evaporator hidden within the bowels of your dash actually cool down.

If the gas is low (because of a leak) or the variable vane isn’t adjusted correctly (faulty compressor solenoid or faulty wiring) or the clutch pulley doesn’t engage (faulty clutch or wiring), then the evaporator can’t become cool… Also, if the ac line pressure becomes too high, the system is shut down...

With a working ac system, the evaporator will get cold and a fan within a big airbox under your dash will channel air through the cold evaporator and our the appropriate vents depending on what you’ve set. For this to work, there are vanes within the airbox which open or close paths that channel the air through the airbox. These vanes are operated via small motors bolted to them and controlled by the system itself. These vanes can fail to operate because of a faulty motor (easy to replace) or some mechanical fault (a pita to fix) or because they've fallen out of calibration (there is a method to recalibrate them).

Wit( a working system, sometimes the evaporator will ice up and air can’t pass through it but as the system isn’t getting cold that’s not a likely issue.

So as a first step, pop the bonnet and look along all the ac lines for any oilyness around the ac fittings and especially at the rubber to hardline crimp joint. Oilyness is an indication that you've had an ac gas leak which is especially easy to see if the motor itself is nice and clean (and/or you have a uv torch). However, the condenser (front ac radiator) is a little harder to check as it’s behind the front bumper while the evaporator is hidden under the dash within yje bowels of the hvac airbox. Low gas will stop the system from working. If you spot what looks like a leak, best to take it to an ac specialist as it’s a quick and easy check to connect an ac manifold gauge set which will highlight what pressures are occurring within. If there are no oilyness and thus probably no leaks, they care easy to miss as not everything can be seen, so again ac specialist may be the go.

You can also check around the compressor. If it has a clutch pulley, which will have one 12v wire and maybe an earth wire, check its operation as it should be visible when it’s working. A clutch pulley is two parts, the inner part is connected to the compressor which doesn’t spin is ac is off and an outer bit which springs with yje accessory belt when the engine is running. When the clutch pulls is energised, the spinning pulley with the belt will move in a few mm and grab the inner pulley which starts to spin the compressor shaft. With a spinning compressor, the ac outlet pipe (the one going to the condenser) will be hot while the fatter one near the firewall (coming from the evaporator) will be cold (hand may have condensation on it if it’s a humid day).

If it looks like the system has gas and the compressor is working yet you still don’t get cold air, it’s likely an issue with the hvac airbox vanes and/or vane motors.

 

[Anthony .]

Here’s a simplified generic rundown of an ac system…

[TLDR]
Take it to an ac specialist so they can check the system has gas.

[The Long Story]
Some commodores used a variable vane compressor (which may or may not have incorporated a clutch pulley arrangement) while others had an older style fixed ratio compressor with a clutch pulley to engage the compressor. The system also has high and low pressure sensors within the ac lines and logic within some module that controlled the whole apparatus.

To turn on your ac, you’d press the ac button which causes stuff to automagically happen and if all is ok yje lamp goes on. Before the ac system can actually operate, system logic would check to ensure that there is enough gas within the ac lines using the low pressure switch. If pressure is ok, it would turn on the ac compressor by either adjusting the variable vane (PWM signal) and/or switching on the clutch pulley (+12v) depending on the hardware in your car.. Then the ac compressor will be spun by the engine and it can then do its job which will see the evaporator hidden within the bowels of your dash actually cool down.

If the gas is low (because of a leak) or the variable vane isn’t adjusted correctly (faulty compressor solenoid or faulty wiring) or the clutch pulley doesn’t engage (faulty clutch or wiring), then the evaporator can’t become cool… Also, if the ac line pressure becomes too high, the system is shut down...

With a working ac system, the evaporator will get cold and a fan within a big airbox under your dash will channel air through the cold evaporator and our the appropriate vents depending on what you’ve set. For this to work, there are vanes within the airbox which open or close paths that channel the air through the airbox. These vanes are operated via small motors bolted to them and controlled by the system itself. These vanes can fail to operate because of a faulty motor (easy to replace) or some mechanical fault (a pita to fix) or because they've fallen out of calibration (there is a method to recalibrate them).

Wit( a working system, sometimes the evaporator will ice up and air can’t pass through it but as the system isn’t getting cold that’s not a likely issue.

So as a first step, pop the bonnet and look along all the ac lines for any oilyness around the ac fittings and especially at the rubber to hardline crimp joint. Oilyness is an indication that you've had an ac gas leak which is especially easy to see if the motor itself is nice and clean (and/or you have a uv torch). However, the condenser (front ac radiator) is a little harder to check as it’s behind the front bumper while the evaporator is hidden under the dash within yje bowels of the hvac airbox. Low gas will stop the system from working. If you spot what looks like a leak, best to take it to an ac specialist as it’s a quick and easy check to connect an ac manifold gauge set which will highlight what pressures are occurring within. If there are no oilyness and thus probably no leaks, they care easy to miss as not everything can be seen, so again ac specialist may be the go.

You can also check around the compressor. If it has a clutch pulley, which will have one 12v wire and maybe an earth wire, check its operation as it should be visible when it’s working. A clutch pulley is two parts, the inner part is connected to the compressor which doesn’t spin is ac is off and an outer bit which springs with yje accessory belt when the engine is running. When the clutch pulls is energised, the spinning pulley with the belt will move in a few mm and grab the inner pulley which starts to spin the compressor shaft. With a spinning compressor, the ac outlet pipe (the one going to the condenser) will be hot while the fatter one near the firewall (coming from the evaporator) will be cold (hand may have condensation on it if it’s a humid day).

If it looks like the system has gas and the compressor is working yet you still don’t get cold air, it’s likely an issue with the hvac airbox vanes and/or vane motors.

Many thanks. Looks like I will have to take it to an AC specialist. Will try the suggestions you made.
What do you think about the grinding sound it made?

 

[krusing]

You possibly have some gas in the system, just enough to fire the compressor up,
However, the high preassure line/pipe between the condenser and the bundy pipe to the compressor, had a tendency to leak at the compression fittings (top and bottom),
I have a similar cool air (not cold) and waiting for it to stop working,

Because sure as hell, I’m not paying some AC monkey to charge me to vac my gas out,
Then vac the system, and charge me for my gas, to re-charge the system with my gas.
Because that’s what they do, unbeknown to the unsuspecting,
How I know, a number of years a go,
I had a friend of mine that was a re-fridge mechanic, and made a ship of money regassing systems.

 

[lout]

i think the foot setting is a different issue to your ac, which has been covered
i think an actuator may have stripped its gears
you can try an auto cal and listen for anything strange

Replacing Air Conditioner (HVAC) Actuator – VE Commodore | AutoInstruct

This guide will show you how to replace the air conditioner (HVAC) actuator on a Holden VE Commodore. This part is known to commonly fail on Series 1 models.

www.autoinstruct.com.au

 

[FalconF16]

Known to fail on the VE Series 2 as well i might add.

 

[FalconF16]

$80 for a new one on Ebay.

 

[Fu Manchu]

Known to fail on the VE Series 2 as well i might add.

What is?

 

[Skylarking]

You possibly have some gas in the system, just enough to fire the compressor up,
However, the high preassure line/pipe between the condenser and the bundy pipe to the compressor, had a tendency to leak at the compression fittings (top and bottom),
I have a similar cool air (not cold) and waiting for it to stop working,

Because sure as hell, I’m not paying some AC monkey to charge me to vac my gas out,
Then vac the system, and charge me for my gas, to re-charge the system with my gas.
Because that’s what they do, unbeknown to the unsuspecting,
How I know, a number of years a go,
I had a friend of mine that was a re-fridge mechanic, and made a ship of money regassing systems.

Aside from the shitfuckery of "licenced ac experts" degassing a system and regassing it using your old gas, with some potential added contaminants from their equipment, It aint a great idea to let the gas slowly bleed out of your car's ac system while using it (just because it cools a little bit while hissing which some think is still ok).

Why? Leaking gas carried ac oil with it and there isn't a huge amount to start with. With gas loss and associated loss of oil comes risk so you may find your ac compressor starts to suffer mechanically... Then not only has one got to find the leak, fix it and regas, they may also have to buy a new compressor

 

[Skylarking]

What do you think about the grinding sound it made?

An AC system will start to hiss as gas gets low (i think the sound is gass goi9ng through the orifice or tx valve rather than liquid vaporising).

But grinding sounds are mechanical in nature which points to the vanes and motors (actuators) as mentioned by @lout if they come from the hvac airbox under dash area