Thread: D4 A/C Compressor issue

Originally Posted by PerthDisco

Is this valve sold separately and is it located externally on the compressor? Does gas need removing to change it?

Valves are available. Only works occasionally. I changed mine and it didn’t improve it.

Yes degas and regas and as mentioned, it’s difficult to get to. Mine was changed when the body was off but it can be done from the wheel arch.

I’d save the money for a new compressor.

Originally Posted by samandfee

Thank you guys

And Redtail Yes thats the problem they say, these guys come highly praised from Kevin at Rovertech in Perth.

Its in today and pick up tomorrow ………….just under 1K and hopefully back to COOL air.

FYI - Kevin@Rovertech doesnt do this work now. I did contact them last Friday. They recommend the work to be carried out by AutoOWL.

I'm yet to decide how to proceed, since its inconvenient with work etc.

Update,

Went to another regas place(2nd time)who put the gauges on, read and found very high pressure in the lines, did not bother attempting to regas as doesn’t seem to think it’s required. Gauges needles were slow to move upon reving, and took a while stabilise when switched off.. Briefly determined compressor is functional. I mentioned the disco’s common to compressor valve failures, then told me there’s pressure in the system so appears to be fine. Suspected highly of the txv to look at.

I then went else where to a local auto elec(3rd time) near home and said to regas. Was told to leave it there for a couple hours as they had a few cars in. Came back to pick it up and there you go, it’s relatively cool (not typical A/C icy cold). So it’s now back to what it was a few weeks back, cool air and not just fan.

So clearly I’m partially unhappy with the outcome but I’d thought I would give it a week before complaining while I scratch my head. One thing I definitely noticed is for the past few months, I don’t get the water dripping from the A/C drain pipes.

Anyway, cut the story short - my viscous fan had been having occasionally ticking on cooler morning starts. Never thought about it much. Being circled with D4 friends, we compared the viscous fan airflow output when the cars idled side by side. Holy ****, mine was barely outputting much airflow at all, both cars had been driven a good 30km before the test. So, test swapped the viscous fans and guess what? High volume Airflow and A/C is now back in full force and Icy Cold!

1) I'm now wondering if the auto elec regas the A/C correctly when the viscous fan was not functioning correctly?
2) With a poor performing fan, what damages were I have caused with running the engine at higher temperatures...

You won’t have caused any damage. If it had been telling you it was overheating and you kept going you would have, but you didn’t.

Interesting on the fan.

Originally Posted by imaz

So, test swapped the viscous fans and guess what? High volume Airflow and A/C is now back in full force and Icy Cold!

For future reference, that would have been a 30 second diagnostic with an IID tool. Check the system high side pressure and the compressor valve position. With poor condenser airflow the high side pressure will steadily increase until it reaches the "limit" whereby the HVAC unit will throttle back the compressor.

If the compressor is duff or the valve is stuck, the valve position would be high with a low high-side pressure and high evap temperature.

Diagnosing the fan would have been the same. Check the fan RPM vs the fan PWM control.

Originally Posted by BradC

For future reference, that would have been a 30 second diagnostic with an IID tool. Check the system high side pressure and the compressor valve position. With poor condenser airflow the high side pressure will steadily increase until it reaches the "limit" whereby the HVAC unit will throttle back the compressor.

If the compressor is duff or the valve is stuck, the valve position would be high with a low high-side pressure and high evap temperature.

Diagnosing the fan would have been the same. Check the fan RPM vs the fan PWM control.

Hi Brad
How does one distinguish between the pressure limit being met and the compressor throttling back versus normal operation? What does normal operation look like? I’m interested to take a look at mine.

As for the fan you’re saying to check actually rpm versus commanded rpm presumably? You’d think there would be a DTC flagged if it’s operating outside of commanded

Either way, I’m going to do this diagnosis on mine, though I’m pretty sure at 300k km my compressor is simply shagged

Originally Posted by BradC

For future reference, that would have been a 30 second diagnostic with an IID tool. Check the system high side pressure and the compressor valve position. With poor condenser airflow the high side pressure will steadily increase until it reaches the "limit" whereby the HVAC unit will throttle back the compressor.

If the compressor is duff or the valve is stuck, the valve position would be high with a low high-side pressure and high evap temperature.

Diagnosing the fan would have been the same. Check the fan RPM vs the fan PWM control.

You are absolutely correct! Here is the error.

Any aircon bloke should have picked that up..I feel for ya mate.. As soon as you see high head pressures you put a hose on the condenser and see how it reacts.. If il the vent temps and pressure drops. It's pretty simple. Good pickup..


Actually after a vac, when putting the right amount of gas in. Old mate should have known the head pressures could only be caused by the condenser, get your money back. He's an idiot.