Alfa Romeo Owners Club of Australia Forum

Technical => 932 Series (156, GTV, Spider, 147, GT, and 166) => Topic started by: poohbah on October 30, 2018, 03:26:22 PM

Title: 156 A/C - basic questions
Post by: poohbah on October 30, 2018, 03:26:22 PM
Folks, does anyone have a basic diagram showing where the A/C receiver/dryer for a V6 156 is located?

In fact does anyone have an engine bay diagram showing where all the AC components are?

And how hard/easy is the dryer to get to?

(I'm not looking to remove it myself, just doing some basic research)

Title: Re: 156 A/C - basic questions
Post by: bazzbazz on October 30, 2018, 04:02:05 PM
Need your VIN number to check.
Title: Re: 156 A/C - basic questions
Post by: poohbah on October 30, 2018, 04:07:26 PM
Cheers Bazz.

ZAR93200001082803

I'm trying some amateur sleuthing to work out why AC not working. Was regassed before last summer and worked okay, but no longer blowing cold. I can hear clutch engaging.
Title: Re: 156 A/C - basic questions
Post by: Citroënbender on October 30, 2018, 04:40:47 PM
Does the fat refrigerant pipe from firewall to compressor get (literally) icy cold when the AC clutch is on?
Title: Re: 156 A/C - basic questions
Post by: poohbah on October 30, 2018, 04:44:24 PM
No idea, will try it when I get home. But if you have AC diagram identifying everthing, that would help. Can't even see the compressor from above. The donk pretty much fills the space!
Title: Re: 156 A/C - basic questions
Post by: poohbah on October 30, 2018, 05:01:02 PM
If you mean the pipe circled, the answer is a big fat No. Just checked and was warm/hot with AC on.

Supplementary question - should the nozzle in the circle have a cap?
Title: Re: 156 A/C - basic questions
Post by: Citroënbender on October 30, 2018, 05:44:45 PM
Yes, a low pressure 134A cap is missing. They're generic.

Warm pipe means it's not pumping. Is the compressor clutch way, way too hot to touch?
Title: Re: 156 A/C - basic questions
Post by: poohbah on October 30, 2018, 05:55:19 PM
No idea CB - I can't even see the compressor from above and there's no room to get my arm in and under - maybe it's accessible from underneath?
Title: Re: 156 A/C - basic questions
Post by: bazzbazz on October 30, 2018, 07:08:58 PM
Clutch will still engage if the system is low on gas and not cooling properly, the system has to get near empty before the pressure switch will inhibit the system.

The receiver/drier should be found under the drivers side front guard forward of the wheel. Its the aluminium cylinder about the size of a 600ml coke bottle.



Title: Re: 156 A/C - basic questions
Post by: poohbah on October 30, 2018, 07:29:17 PM
Cheers Bazz,

I guess I should get it pressure checked first then - but really shouldn't need another regas after only 12-18 months should it?
Title: Re: 156 A/C - basic questions
Post by: poohbah on October 30, 2018, 08:04:45 PM
Just ducked into the work carpark for another squizz. Thanks Bazz - have now located the receiver/dryer.

As for the compressor, is the compressor pulley and clutch plate the one I can just see protruding slightly directly beneath the cambelt cover (I can just see the tops of the bolts that hold the plate on)?

If so, then the clutch plate seems to be spinning while engine is running whether the AC is switched on or not.

Yet I can still hear it click when I turn the AC on or off.
Title: Re: 156 A/C - basic questions
Post by: Citroënbender on October 30, 2018, 08:08:25 PM
Bazz - Do the sixes chafe through a condenser hose like the fours?
Title: Re: 156 A/C - basic questions
Post by: poohbah on October 30, 2018, 08:13:08 PM
Scratch my last observation. I managed to find a pic of an exposed V6. I have circled the pulley I can actually see spinning - I gather its an idler? The compressor is obviously lower down and sits beneath it, where I can't see it from above.

Title: Re: 156 A/C - basic questions
Post by: Citroënbender on October 30, 2018, 08:21:32 PM
I think I accidentally reported your post, apologies.  ???

Gas should stay in a healthy system for years with regular use. Barring an accident the most likely things are compressor air gap excessive, hose/tube damage or possibly a failed displacement control valve in the compressor if it's an SD7V16 or similar.
Title: Re: 156 A/C - basic questions
Post by: poohbah on October 30, 2018, 08:29:23 PM
ha - the naked V6 pic is a bit pornographic....

Is the displacement control valve mechanical or electrical - and can it be replaced on its own, or does it mean whole compressor is cactus?
Title: Re: 156 A/C - basic questions
Post by: Citroënbender on October 30, 2018, 08:39:15 PM
They're not serviced as a spare part by Sanden but are all over third party sales sites.

eg: http://latticetech.com/control_valves/control_valve_ltcv02.html

On the four pot 932 series, there is frequently chafing to one refrigerant hose on the fan shroud edge. It's enough to cause the gas to leak.
Title: Re: 156 A/C - basic questions
Post by: poohbah on October 30, 2018, 08:42:41 PM
Cheers CB.

I'll have a poke around from the ground and see if I can see any chafed hose.

Probably the most sensible thing to do is swing by the workshop and see if I can get a pressure check and quick diagnosis.
Title: Re: 156 A/C - basic questions
Post by: bazzbazz on October 31, 2018, 01:08:45 AM
The item you have circled in the V6 pic is the power steering pulley. The A/C compressor is the unit & pulley below the one you circled.

The most common cause of slow leaks other than physical damage are faulty/dried/perished connector seals/O-Rings.

I would suggest that as you have most likely lost gas over a short period of time that you have a leaking seal somewhere. In this instance, as I am a mobile service and am limited to how much equipment I can carry, I recommend clients take the car to a A/C Service Center that just specializes in A/C. They have the ability to pressure test the system with nitrogen and will find the leak quickly, its what they do.

Otherwise, without the specialist tools/equipment you can be chasing your tail, in both time & money.
Title: Re: 156 A/C - basic questions
Post by: poohbah on October 31, 2018, 10:32:06 AM
Cheers bazz.
Title: Re: 156 A/C - basic questions
Post by: poohbah on November 03, 2018, 06:44:21 PM
Jacked her up this arvo and had a good poke around. Compressor clutch is definitely engaging, and couldn't see any obvious chafed hosing, or anything obvious amiss really. Nothing left to do now but seek professional diagnosis ...
Title: Re: 156 A/C - basic questions
Post by: Citroënbender on November 03, 2018, 08:55:31 PM
Good work eyeing it up first though. The other cheap fun tool is a UV torch and appropriate safety goggles often sold together as a kit.
Title: Re: 156 A/C - basic questions
Post by: poohbah on November 03, 2018, 09:08:26 PM
Good tip CB. Might pick one up next time I'm at supercheap.
Title: Re: 156 A/C - basic questions
Post by: Citroënbender on December 01, 2018, 10:50:34 PM
Any progress?

Now you've got a nice new screen you can get the AC icy cold - so when it sallies forth out the demister vents, your glass cracks all across the bottom...
Title: Re: 156 A/C - basic questions
Post by: poohbah on December 01, 2018, 11:40:44 PM
Not yet - have parked that issue for the moment as I just had to spend a fair wad on the GTV (full service, wheel bolts and new tyres).

Will get around to it when I've had a break from spending!
Title: Re: 156 A/C - basic questions
Post by: bazzbazz on December 02, 2018, 12:02:47 AM
Quote from: poohbah on December 01, 2018, 11:40:44 PM
Will get around to it when I've had a break from spending!

Like that's gonna happen . . . .  ::)

;D
Title: Re: 156 A/C - basic questions
Post by: Citroënbender on December 04, 2018, 09:24:42 PM
Was that "window cut" your experimentation to see if the TXV could be replaced in-situ?

I note the 147 and facelift 156 seem to share expansion valves (by part number) and quite possibly evaporators - with just slight differences in the intermediate tubing from valve to firewall junction. 

When you look at the regs for a warrantable replacement of a Sanden compressor, it does indeed make the process seem unviable as they deem modern evaporators to be unsuited for flushing - and therefore must be replaced... 

Unrelated/related overall:

To date I haven't seen any stuff on the internet for testing of the compressor's internal control valve (mechanical type) - whether the rating is a simple "cracking pressure" like an old diesel injector or when it is fully open (or if there is any meaningful difference between these two points).  I'd like to know because the pressures are quite small and it would be easy/fun to build a simple tester.  There is informed commentary from some sources saying the valves are more often than not the root of a "tired" SD7V16 compressor per gauges, but it would be nice to have the ability to discern if/when this is actually the case. 
Title: Re: 156 A/C - basic questions
Post by: poohbah on December 05, 2018, 12:37:31 PM
Quotef you want to know where the expansion valve or TX valve is on a 156 JTS

Is it the same in a Series 1 V6?