Technical Air con compressor burning smell

[NMH]

Hi,
New to this so really looking for some advice as drawn blanks everywhere else. I have a Stilo Blue, 1.4. Goes like a dream and even at 130K miles is lovely to drive however I have a recurring Air Con problem which is getting expensive. The car is serviced regularly at each service interval, I do to many business miles to scrimp on that.
Beginning of 2012 I started smelling a burning smell once I pulled up at journeys end. Didn't think to much of it but had it checked out by garage and nothing was found. Several weeks later the air con worked intermittently. I had to switch off within the cabin and on again and it would start working again until a week or so later the A/C compressor packed in, (It was the original and had made 110K miles). So I again had it checked and a replacement A/C compressor fitted.
Great all started working again. This one has lasted 1 year! 3 weeks ago I noticed that same 'burning' smell when pulling up at the end of a journey and then 1 week down the line the A/C compressor has stopped working, does not cut in and the A/C is nonoperational. Local garage has checked and Compressor has failed again.

Does anyone know what might be happening or what might cause this?
I am very reluctant to put another compressor on if it is only going to last another 12 months!!!
Would non-replacement of the pollen filter cause something like this? (forgive me if this is very stupid question!!).
To add to the information my garage did locate a corroding fuse box (under bonnet next to battery, common problem from what I understand) which I also had replaced about a year ago.
Could the issue be related to electrics?
I have checked this out this time with standard diags, cabin switch works, fan on 0 position, it turns on fan when a/c is switched on. Fuses check out and relay checked out. Condenser connections all look good.

Any advice or assistance greatly appreciated.
Cheers

 

[alexGS]

First thing that comes to mind is the blower fan motor or its speed controller - but that would give the burning smell inside the car rather than under the bonnet - which is it?

The burning smell under the bonnet could be the belt running over a seized compressor pulley. The pulley should freewheel when the A/C is turned off. If it doesn't, the bearing has failed; this can be replaced without replacing the whole compressor. The other possibility is that the A/C compressor itself (not just the pulley) has seized for a particular reason. I would suggest taking this immediately back to the garage/workshop that replaced the compressor - they should have the first opportunity to diagnose and offer an explanation. One year is not a normal lifespan and surely some sort of goodwill contribution to the cost of replacement is possible here.

If the compressor has failed, the cause cannot be electrical or that the pollen filter wasn't changed. Really, the only cause is that the refrigerant charge ("re-gassing") was incorrect, not enough oil or wrong type of oil was put in to the refrigerant circuit, or that the pulley bearing was overloaded due to an incorrectly-fitted belt (unlikely). So I think someone has made a mistake - we all make mistakes, and we all benefit from the chance to put mistakes right and learn from them. Expecting the garage to cover all costs would be unreasonable in light of the years' worth of functional service, but the job should certainly cost you less than the first time around.

If you are really getting nowhere with the garage even after pressing them for details about what has happened and how they can stop it from happening again, then you'll just have to pick a different air conditioning specialist and get their diagnosis - sorry about that, but in my opinion, something's not right with the work done if the compressor itself has failed again. Usually on the Stilo, an aluminium pipe breaks off and leaks out the refrigerant, but in that situation the compressor will stop before it is damaged.

-Alex

 

[NMH]

Hi Alex,
Thanks for the reply. The burning smell was definitely under the bonnet and weirdly I don't smell it through the vents when in the car but it is apparent when I get out or open the drivers door. Now the A/C is not working the smell has stopped!

I did wonder if the compressor pulley had seized but I can free wheel it with my hands when the engine is off. When I do free wheel it I do get a feeling of resistance and then release as if the pump seems operational but the compressor never engages or operates when the car is running.

I have it booked in to the garage that did the work next week so hopefully they will get to the bottom of things.
Still perplexed as to the burning smell and only really linked it to the A/C compressor because the a/c fails soon after or if I turn the a/c off at the dial on the dash.

Cheers
Neil..

 

[NMH]

Hi
So an update to my problem is that I have just got my Stilo back from the garage and it appears that the smell 'could' be coming from the corroded fuse box which sits under the bonnet next to the battery.
My air con is working again but we are unsure as to how long due to the level of 'visible' (as opposed to non visible) corrosion or furring up of the relay and fuse terminals.
This is actually the second of these fuse boxes that has been fitted and it was a corrosion problem last time.
My car was bought brand new by my father in law in 2006 and I bought it off him 3 years ago so I have a full service history on the car.
Looks like another of these fuse boxes now needs to be fitted.

Can anyone advise on the part number so that I can see whether I can source a replacement without paying dealer prices??
Stilo Blue, 1.4 16v 2006.

Also does anyone know of a good way to waterproof these fuse boxes??

I have seen the guide in the Stilo-guides on cleaning/drying the fuse box but I think mine might be past that stage but I would like to protect the next one from the same fate!!

I have been told of a silicon spray but that I could use but unsure what make, type or where to get it?

Thanks
Neil

 

[mhowse]

Do you have a fuse / battery cover as they did come with those fitted
I was daft enough to leave mine off for a few days a while back and got caught out in the rain, managed to dry out my fuse box area and clean up connectors, but since then I make sure have the cover in place and no problems since that is on a stilo with air con..if you do not have the cover may be worth hunting for one from breakers or auction sites

 

[NMH]

Hi,
Yes still got the original cover but still seems to be exposed somehow. I would have thought that there was enough air flow around that area to dry any moisture away.