Brera aircon mystery - detectives wanted - Alfa Romeo Forum
You are currently unregistered, register for more features.    
 
Thread Tools
(Post Link) post #1 of 25 Old 30-01-19 Thread Starter
Status: -
AO Member
 
Join Date: Nov 2008
Location: United Kingdom
County: Durham
Posts: 183
Brera aircon mystery - detectives wanted

I have a mystery fault with the aircon which Iím hoping someone may be able to help with.

The system works for a few weeks and then stops due to low pressure, so the gas is presumably getting out somewhere. What is odd though is that it has been pressure tested numerous times and always holds the pressure (proper nitrogen test, not just holding a vacuum). Today it was nitrogen tested at very high pressure and was rock solid for 30 minutes. No sign of any leak, no hissing, nothing. Itís also been gassed up a number of times, with dye added, but they spent two hours on it today and could not find any trace of a mark from the dye.

So the question is can anybody think of a potential leak which ticks these boxes: (a) small enough to hold very considerable pressure for 30 minutes, and (b) sufficiently hidden away that the stain the escaping dye should be leaving cannot be seen?

Could it be the case that the leak is so small that somehow the gas can get out but the dye canít? Can that even be a thing? The only other thing I thought is that clearly the pressure test is done with the system not running, so might it be something in a moving part which is a causing the leak. Problem with that though is the only moving part is the compressor, and thereís no sign of dye anywhere near it, which presumably rules that out.

The garage and me are completely at a loss on this one. Itís like someone is stealing the gas when Iím not looking. Itís doing my head in and spending £60 every few weeks all summer to recharge it really isnít a sensible solution so any suggestions gratefully received. Help!
Taranty is offline  
Sponsored Links
Advertisement
 
Status: -
AO Silver Member
 
Join Date: Nov 2012
Location: Wiltshire
County: -
Posts: 1,958
Only place I can think it could leak with absolutely no trace is the evaporator,but that is a big strip down as I suspect a dash out job.
johnnyroper is offline  
Status: -
AO Member
 
Join Date: Oct 2016
County: -
Posts: 39
What about the filling valves?
tydytek is offline  
Status: -
AO Silver Member
 
Join Date: Nov 2012
Location: Wiltshire
County: -
Posts: 1,958
That’s also a possibility but I would think there would be dye trace around them?
johnnyroper is offline  
Status: -
AO Member
 
Join Date: Oct 2016
County: -
Posts: 39
It probably would. But not many mechanics check these valves because there is dye anyway - from filling the aircon.
tydytek is offline  
Status: -
AO Silver Member
 
Join Date: Nov 2012
Location: Wiltshire
County: -
Posts: 1,958
Give a good clean with carb cleaner to remove any trace after filling and see if any due forms there,should only get on low side as that’s the fill one
johnnyroper is offline  
(Post Link) post #7 of 25 Old 31-01-19 Thread Starter
Status: -
AO Member
 
Join Date: Nov 2008
Location: United Kingdom
County: Durham
Posts: 183
Quote:
Originally Posted by tydytek View Post
What about the filling valves?
I think you may have nailed it, and I'm kicking myself for not thinking of it because in hindsight it seems so obvious. Pressure test is of course done with the external nitrogen source connected to the car via the valves, but in normal use there is nothing connected to the valves. Thus other than the compressor being engaged that's really the only variable between test and normal use. A leaking valve is effectively inside the system during the test hence system will happily hold the pressure. If it was the condensor leaking then that would presumably mean it wouldn't hold the pressure during the test, so valve is the obvious candidate.

As for the dye, there's a fair amount visible to the naked eye on the thread of the low side valve, but what I think is the clincher is that there's also loads on the underside of the valve cap (see pic). I guess it could have got on the thread when being filled, but the cap would obviously be nowhere near at that point so surely they only way there can be dye inside the cap is if the valve is leaking? Also explains the absence of dye, because it all gets caught inside the cap.

So assuming that's the answer, is there anyway of fixing the valve in situ, or is it a case of replacing the pipe which the valve is part of? I'm guessing the latter but asking just in case there is a simpler solution.
Attached Images
File Type: jpg Valve cap.jpg (149.0 KB, 18 views)
Taranty is offline  
Status: -
AO Silver Member
 
Join Date: Nov 2012
Location: Wiltshire
County: -
Posts: 1,958
Aren’t they just schrader type valves the same as in the tyre valves? Failing that go down a scrapper and screw some out with a tyre valve remover
johnnyroper is offline  
(Post Link) post #9 of 25 Old 31-01-19 Thread Starter
Status: -
AO Member
 
Join Date: Nov 2008
Location: United Kingdom
County: Durham
Posts: 183
Quote:
Originally Posted by johnnyroper View Post
Aren’t they just schrader type valves the same as in the tyre valves? Failing that go down a scrapper and screw some out with a tyre valve remover
Yep, bit more research suggests the valve core is swappable, just need a particular tool to do it. May even be as simple as tightening up the existing one using said tool. There has to be a snag here, this is starting to look like a way too cheap and easy fix!
Taranty is offline  
Status: -
AO Member
 
Jockster's Avatar
 
Join Date: Jun 2017
County: -Cambridgeshire
Posts: 95
Pop down your local bike shop, core's and the tools for it are readily available.
Jockster is offline  
(Post Link) post #11 of 25 Old 31-01-19 Thread Starter
Status: -
AO Member
 
Join Date: Nov 2008
Location: United Kingdom
County: Durham
Posts: 183
Looks like both valves are buggered, popped out at lunch and had a look at the other cap as well and significantly more dye in that one. Given that they appear to be cheap as chips I'll just swap them both out and then hopefully all sorted.

Massive thanks to all for the help on this, it was doing my head in and this was the last in a long running list of problems I've had with the aircon since buying the car last May. I was almost resigned to it being something I'd never get fixed so very happy if it turns out to be as simple as replacing a couple of valve cores.
Attached Images
File Type: jpg Caps.jpg (490.5 KB, 10 views)
Taranty is offline  
Status: Quo!
AO Silver Member
 
alfaitalia's Avatar
 
Join Date: Jan 2010
Location: United Kingdom
County: West Sussex
Posts: 2,292
It won't be the caps...they just cover the valves and have no real sealing ability. If there is dye in them, then the valves themselves need looking at. Could just be residue of the last recharge of course.
alfaitalia is offline  
Status: "Ruby" has been Torpedoed!
AO Member
 
bazzbazz's Avatar
 
Join Date: Apr 2013
Location: Brisbane Australia
County: Queensland
Posts: 464

Member car:

Alfa 156

And yes, they are Schrader type valves but you need the proper ones for automotive A/C and for R134a systems. they are available on eBay.
bazzbazz is offline  
(Post Link) post #14 of 25 Old 11-02-19 Thread Starter
Status: -
AO Member
 
Join Date: Nov 2008
Location: United Kingdom
County: Durham
Posts: 183
Quote:
Originally Posted by bazzbazz View Post
And yes, they are Schrader type valves but you need the proper ones for automotive A/C and for R134a systems. they are available on eBay.
Thanks, I thought that was likely to be the case, presumably seals on the valve need to be same material as A/C o-rings rather than rubber.

I bought a removal tool, but the slot doesn't seem to be deep enough for the A/C valves. It's only about 3mm deep which doesn't seem to be enough to get over the length of the central stem which sticks up (the bit with the spring round it as shown in pics below). I don't think there's anything I'm doing wrong trying to use it, the thing just doesn't engage with the "shoulder" of the valve so can't get purchase to turn it. Is there a specific tool for automotive A/C schrader valves I need to be looking for?
Attached Images
File Type: jpg valve.jpg (41.6 KB, 9 views)
Taranty is offline  
Status: -
AO Silver Member
 
Join Date: Nov 2012
Location: Wiltshire
County: -
Posts: 1,958
Are you able to cut the slot deeper in your tool with a thing cutting disk to make it fit on the valve?
johnnyroper is offline  
Status: "Ruby" has been Torpedoed!
AO Member
 
bazzbazz's Avatar
 
Join Date: Apr 2013
Location: Brisbane Australia
County: Queensland
Posts: 464

Member car:

Alfa 156

As you press the tool in it pushes the valve stem in, allowing the cutout to engage the body of the valve.

Just go and use it, it works.
bazzbazz is offline  
(Post Link) post #17 of 25 Old 12-02-19 Thread Starter
Status: -
AO Member
 
Join Date: Nov 2008
Location: United Kingdom
County: Durham
Posts: 183
Quote:
Originally Posted by bazzbazz View Post
As you press the tool in it pushes the valve stem in, allowing the cutout to engage the body of the valve.

Just go and use it, it works.
I did - twice! The valve stem depressed, but didn't go far enough for the cutout to engage. Pretty sure it wasn't a case of not pushing hard enough, but will give it a third go just to make sure

Quote:
Originally Posted by johnnyroper View Post
Are you able to cut the slot deeper in your tool with a thing cutting disk to make it fit on the valve?
Yeah, think this will be plan b assuming third time lucky doesn't work out. I haven't got a cutting disc but may be able to get the junior hacksaw in there to achieve the same thing.
Taranty is offline  
Status: Over the hill, but still accelerating
AO Member
 
r1200rt's Avatar
 
Join Date: Sep 2014
Location: United Kingdom
County: Cambridgeshire
Posts: 84
I have had the same problem with my spider. The system held 8 Bar at the last check for ages.
I chatted to the Air con guy and he said that it could be the compressor as you have said, or he said replace the dryer.
Your idea about the valves seems really possible. Please report once it has been re-gassed. I would love to know.
Can't you get the valves replaced by the guy who are going to re-gass it, then you won't have the agg of removing them etc.
Looking forward to your next post
r1200rt is offline  
Status: "Ruby" has been Torpedoed!
AO Member
 
bazzbazz's Avatar
 
Join Date: Apr 2013
Location: Brisbane Australia
County: Queensland
Posts: 464

Member car:

Alfa 156

If the tool doesn't seem to work send us a photo of the tool, you may be using something different to what I am thinking.
bazzbazz is offline  
(Post Link) post #20 of 25 Old 13-02-19 Thread Starter
Status: -
AO Member
 
Join Date: Nov 2008
Location: United Kingdom
County: Durham
Posts: 183
Quote:
Originally Posted by r1200rt View Post
I have had the same problem with my spider. The system held 8 Bar at the last check for ages.
I chatted to the Air con guy and he said that it could be the compressor as you have said, or he said replace the dryer.
Your idea about the valves seems really possible. Please report once it has been re-gassed. I would love to know.
Can't you get the valves replaced by the guy who are going to re-gass it, then you won't have the agg of removing them etc.
Looking forward to your next post
If you had dye in the system it should be reasonably easy to rule out compressor and dryer, they are both easily visible so any inspection with the relevant light ought to have shown up some dye. The big giveaway on mine was the underside of the black filler caps, they were both covered in dye as you can see on the pics upthread. You are right, I'm sure I could get the garage to do the valves, but I'm being stubborn now and want to get them done myself! It's also a good excuse to buy tools and car parts, even if they are only small little things.

Quote:
Originally Posted by bazzbazz View Post
If the tool doesn't seem to work send us a photo of the tool, you may be using something different to what I am thinking.
Here's what I have. It calls itself a tyre valve tool, so perhaps that's the issue. I know they are essentially the same sort of valve, but central stem on these AC valves looks a fair bit longer than what's in the tyres.
Attached Images
File Type: jpg Tool.jpg (241.1 KB, 9 views)
Taranty is offline  
Status: "Ruby" has been Torpedoed!
AO Member
 
bazzbazz's Avatar
 
Join Date: Apr 2013
Location: Brisbane Australia
County: Queensland
Posts: 464

Member car:

Alfa 156

You need a proper tool for A/C valves, they are double ended and have two different size cut outs at each end for different types of A/C valves.
bazzbazz is offline  
(Post Link) post #22 of 25 Old 15-02-19 Thread Starter
Status: -
AO Member
 
Join Date: Nov 2008
Location: United Kingdom
County: Durham
Posts: 183
Quote:
Originally Posted by bazzbazz View Post
You need a proper tool for A/C valves, they are double ended and have two different size cut outs at each end for different types of A/C valves.
Ah, I know what you mean, one of these fellas. Looks like the shaft is wider, and is drilled out inside which gives the valve stem somewhere to go and then allow the cut out bit to engage the valve shoulder.
Attached Images
File Type: jpg Tool 2.jpg (18.4 KB, 7 views)
Taranty is offline  
(Post Link) post #23 of 25 Old 2 Weeks Ago Thread Starter
Status: -
AO Member
 
Join Date: Nov 2008
Location: United Kingdom
County: Durham
Posts: 183
A belated update on this. Had it regassed, and it seemed to be working ok, although one of the (replaced) valves has shown a sign of a small leak again. No low pressure fault code though, so system is still sufficiently well charged. What I did notice though is that when it had been on for a while on the ďlowĒ climate control setting there was a build up of ice on the pipe which goes through the bulk head from the engine. I know it should obviously be pretty cold, but Iíve not seen actual ice on an air con pipe before.

Currently that particular issue is not repeating itself, because again it isnít working. As noted above there isnít a pressure issue, no fault codes and I can hear the relay by the battery clicking on and off when the aircon button is pressed on and off. Therefore no issue at a system conditions level, itís trying to turn the compressor on but that last part in the process isnít working. Iím assuming the compressor will be like the one on my 156 with a 12v feed which activates the clutch, so will run a separate cable direct from the battery and see if the clutch clunks. I can also check the standard feed to it with the multimeter and see if thereís any change when the relay is activated. Is there anything else I need to be checking, or should that pin it down?
Taranty is offline  
Status: -
AO Member
 
Temple60's Avatar
 
Join Date: Dec 2015
Location: Canberra, ACT
County: -Australia
Posts: 38
Same Issue 3 years back in Australia

I had the same issue almost exactly three years back in my Brera. The compressor was clicking so no issues there but after a few weeks I had no pressure or gas. I took it to an excellent A/C place and we had a close look - the problem with the Brera is that when it was changed from left to right hand drive for places like the UK/AUS they didn't change anything under the bonnet - thus many of the workings of the A/C are now behind the steering column - not the glove box as it would be in a left hand drive car and you can't really get to leaks etc. The dye issue was the same as yours. What we did was put some A/C gap clogging agent spray into the A/C as we worked out that the leaks were coming from very, very small leaks thus it worked for a few weeks then stopped. This was 3 years ago and I have had a perfectly serviceable A/C since (pretty important in an AUS summer!!!) so fingers crossed it continues. I would recommend this approach as a easy to do fix, as any other is really complicated.

Hope this helps

Richard
Temple60 is offline  
Status: -
AO Silver Member
 
Join Date: Nov 2012
Location: Wiltshire
County: -
Posts: 1,958
Quote:
Originally Posted by Taranty View Post
A belated update on this. Had it regassed, and it seemed to be working ok, although one of the (replaced) valves has shown a sign of a small leak again. No low pressure fault code though, so system is still sufficiently well charged. What I did notice though is that when it had been on for a while on the “low” climate control setting there was a build up of ice on the pipe which goes through the bulk head from the engine. I know it should obviously be pretty cold, but I’ve not seen actual ice on an air con pipe before.

Currently that particular issue is not repeating itself, because again it isn’t working. As noted above there isn’t a pressure issue, no fault codes and I can hear the relay by the battery clicking on and off when the aircon button is pressed on and off. Therefore no issue at a system conditions level, it’s trying to turn the compressor on but that last part in the process isn’t working. I’m assuming the compressor will be like the one on my 156 with a 12v feed which activates the clutch, so will run a separate cable direct from the battery and see if the clutch clunks. I can also check the standard feed to it with the multimeter and see if there’s any change when the relay is activated. Is there anything else I need to be checking, or should that pin it down?
Ice on the pipe is a sign that the air flow over evap is poor check pollen filter. Or there is a problem with the TEV causing high pressure which would also cause the compressor to not run.
johnnyroper is offline  
Reply

Go Back   Alfa Romeo Forum > Supported Alfa Romeo Models > Technical & Vehicle Assistance > Alfa 159, Brera & 946 Spider

Tags
aircon , brera , detectives , mystery , wanted

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome