Thread: D4 A/C Compressor issue

Originally Posted by imaz

Yeh cool, pm and I shall call.

I was reading the sanden booklet and did notice oil recommendations, and compressor was pre-oiled, but as you mentioned is not enough for dual AC’s. I didn’t see where to add the oil, some compressor’s have an oil catchment from videos I had seen.

Goes in through the plug in the Center of the body. There is a post from me somewhere on here about how much to put in. Even without rear air it's not enough.

Originally Posted by josh.huber

Goes in through the plug in the Center of the body. There is a post from me somewhere on here about how much to put in. Even without rear air it's not enough.

Old compressor is out, here is the oil. Looks ok to me, no traces of anything metallic that I can see.


The wire to the electronic valve might have a pinch.

Short update, fixed.

Regassed to 900g, outside temp today 27c, while inside cabin is ~4.1c.

New compressor is silent in that no clicks when engaged ON/OFF when you hit the A/C button.

End.

Originally Posted by imaz

Short update, fixed.

Regassed to 900g, outside temp today 27c, while inside cabin is ~4.1c.

New compressor is silent in that no clicks when engaged ON/OFF when you hit the A/C button.

End.

Job well done imaz

Interesting, so the clicking noise is an indicator that something is wrong? 217000km on original compressor, had it regassed earlier this year as a preventative measures and still cooling as usual.

Originally Posted by Eric SDV6SE

Job well done imaz

Interesting, so the clicking noise is an indicator that something is wrong? 217000km on original compressor, had it regassed earlier this year as a preventative measures and still cooling as usual.

No idea, I can hear it slightly click now. Perhaps it’s a new compressor just burning in.

At the price I got the new part for, there is no reason to swap the Valve.

For reference here are the stats of the functioning system at idled/parked.

Originally Posted by BradC

A lot of generalisations in this post.

"Generally" an issue with the valve will start to cool within 10's of kilometers or if you really thrash it (lots of revs and vibration). You did 400km and it didn't cool, so that's probably not a good indicator for your car.

I've never seen a mechanic who does AC diagnose a faulty valve. They "generally" just replace the compressor.

*I've* never seen a completely stuck valve. If you are handy with a spanner, get the covers off on a hot(ish) day, set the thermostat as low as it will go and give the valve a couple of whacks with something heavy. See if it's an American valve (ie it responds to violence).

If you can unstick it and get plausibly workable cooling then you might get away with just a valve. "Generally" if its the compressor then the failing compressor will have spread aluminium dust through the system requiring extensive remediation in addition to a new compressor. You can tell when the valve comes out. If it's clean then you're ok. If it has a silvery sludge on it then it's pineapple time.

Most AC mechanics will put a gauge set on the car, run it up and look at the pressures. In the old days, a high low-side reading, and a low high-side reading just said "your compressor is dead", but these days with variable-displacement compressors it ain't necessarily so.

On the flip side, a variable displacement compressor is *always* circulating refrigerant. This stops the seals drying out (unless you are low on gas in which case your lubricant winds up in the evaporator and you lunch the compressor). So on the whole the newer compressors are more reliable. The displacement valve seems to be a real problem on all of them though. The yanks are up to speed on this. The last 3 valves I've bought have been from Amazon US.

Aussie tradies seem to be behind the curve and just replace compressors. Maybe there's more margin on a compressor.

I first learned about this stuff a few years ago when my wifes Golf developed "the delay". I got quoted a compressor, condenser, dryer, TXV and a very expensive hose/evaporator flush (just north of $2k). A $35 valve from Amazon US and a couple of hours in the driveway and it was sorted.

So... are you handy with a spanner?

Brad.... When the A/C compressor is on the car, how viable is it to get to the valve?
Is it basically a compressor out job? If so may as well just do that, but of it can be done through "keyhole surgery" it's probably worth a punt.

Originally Posted by BradC

. So on the whole the newer compressors are more reliable. The displacement valve seems to be a real problem on all of them though. .

Many new vehicles still use the standard compresser,no displacement valve,and they are extremely reliable.

Not having a displacement valve is one less thing to fail,i suppose.

Compresser seals very rarely,if ever fail these days,and the seals on the hoses,and the hoses themselves are very good quality.

Its the poor quality evaporators and condensers that cause most of the issues these days, in some vehicles.

Originally Posted by shack

Brad.... When the A/C compressor is on the car, how viable is it to get to the valve?
Is it basically a compressor out job? If so may as well just do that, but of it can be done through "keyhole surgery" it's probably worth a punt.

When I wrote that post my experience working with the mechanics in and around the disco donk was "a bit less" that I have now. I can't see a viable route to do just the valve on the my D3, and on that basis if I were pulling the compressor I'd be replacing it with new. All the other cars I've done it on have had a clear and relatively easy route to the valve.

I just grabbed the borescope and went for a poke around just to make sure, and I reckon there's a clear path to the valve, but it looks like to get there you'd need to remove :

• The passenger front wheel
• Upper suspension arm
• Air bag
• Heat shields
• Turbo discharge pipework

And a few other miscellaneous bits.

You might get there with less if you can bend your arm like I can my borescope, but I've never seen it done in any manner that didn't require the assistance of an orthopedic surgeon to put it back together.

So, it's probably a compressor out job on the disco.