GTS aircon rapid clunking noise?

[Kazzer]

When I use the air conditioner compressor activation/deactivation button - there is a rapid clunking noise - only tried it twice and was there on both
occassions. When deactivated the noise goes - is it likely to be the compressor? is there anything else we should check?

Karen

 

[safrane]

Does the clunk stop after a moment with the air con running? Or carry on?

If it continues and there is no chilled air it could be;

If a metallic clunc
No or lack of refrigerant gas
the compressor or its solinoid
compressor bearing

if more of a plastic clunc it could be the vent flaps sticking.

 

[Kazzer]

It continues running - first time we heard it - didint realise it was the air con - when you switch the button to deactivate the compressor the noise stops

there is chilled air - sound is metallic

to check the gas can I take it to Duncan?

 

[Felonious Crud]

Don't use it! Could be the compressor bearing. Get it to a garage, have it up on the ramp and check the pulley wheel. My guess is that bearing's shot. If it comes apart you'll have a stray belt causing mayhem in the engine bay. I'll try and post a video of mine later but it made a clear metallic clicking.

 

[Kazzer]

Oh dear! was going to go for a spin this aft

I have a warranty - should I use that?

Nearest Masser garage is Dick Lovetts or Duncan who I use for the Alfas

Whats best to do please

 

[Felonious Crud]

I *think* you can drive it, but keep the air con off. Warranty should cover it if it includes wear and tear. I drove mine ok until I got the new compressor, but with the a/c de-gassed and off.

 

[StuartW]

Good luck with that Karen & keep us posted

 

[safrane]

I am sure Richard will cover it even if it is not covered by the warranty...just keep the windows down and listen to that 4.7 burble.

 

[Mr K]

Had this issue with my QP. Common fault, the pulley bearing comes loose on the compressor casting "nose", wears the nose and starts rattling when the a/c is on. The compressor continues to work, but if you don't replace it it will eventually fail. If it's quiet with the a/c off you can continue driving it, with the a/c off. No need to get it de-gassed ahead of getting the compressor is replaced, leaving it switched off is fine.

Use the warranty if you can - it's a £1k+ job. I sent mine off to Compressortech in Warwick, but they couldn't get hold of a good casing so I had to buy new, from Eurospares at £750 (seems to be on offer at £625 now). Compressortech was getting some new ones in for June, so may have stock now at about £500. Make sure it's a genuine Delphi - there are Chinese copies advertised on Alibaba which will be finding their way to Europe. Fitting shouldn't cost too much, it's not a big job for someone who knows what they're doing. I reckon £400 labour/regas & £575 to £825 for the parts (compressor, dryer, seals).

I'll do a proper post when I get time, showing how to fit it for fellow DIYers. There's a guide elsewhere saying you need to unbolt exhausts - you don't on the QP, though it's tight!

 

[Felonious Crud]

This is what had happened to mine.

[video]https://youtu.be/mWMRaovPh3M[/video]

I couldn't track down a new compressor for love nor money (well, maybe £1200 + VAT of Maserati money for a new one) so got a recon unit from Compressor Express in Hungary for about £450 inc. taxes and delivery. Looked like new and has a year's warranty. As you'd expect from Ferrari / Maserati you need to be really careful you get the right part - check with the part number off the old unit rather than looking up your year / model on Eurospares.

Mr K's fitting estimate was about spot on - I paid Grimaldi about £350 for fitting and a re-gas.

 

[Kazzer]

Its covered by the warranty confirmed by Richard - so will use that - hopefully I can get it sorted this week - but not around for next couple of days and away at weekend.

Thanks for the info Adam and Mr K - will make sure the correct part is fitted - hopefully I can use my guy not a main dealer as he is closer to me.

 

[Felonious Crud]

Good news! Not a cheap repair otherwise (as I found out!) and not something that you'd want to be without.

 

[EXCF350]

I *think* you can drive it, but keep the air con off. Warranty should cover it if it includes wear and tear. I drove mine ok until I got the new compressor, but with the a/c de-gassed and off.

DON'T USE IT!
I had the same problem with mine, Graypaul Edinburgh replaced it under warranty but said that even if driven with the aircon off and it not making a noise it is still liable to fail at any time and could cause a lot of damage. They showed me it while up on the ramp and the pulley is very wobbly even with the aircon off.

 

[Mr K]

DON'T USE IT!
I had the same problem with mine, Graypaul Edinburgh replaced it under warranty but said that even if driven with the aircon off and it not making a noise it is still liable to fail at any time and could cause a lot of damage. They showed me it while up on the ramp and the pulley is very wobbly even with the aircon off.

That advice is based on a misunderstanding of the failure mode. Main dealers don't dismantle compressors, they just replace with new, so they probably don't have a deep understanding of this issue. This isn't a bearing failure, it's the nose of the compressor that wears, hence the wobble. With the bearing in good condition (no noise) the belt holds it tight on the nose and it can continue to be used with the a/c off until the bearing wears out - could be another 50k miles, who knows! It's academic in a way as I can't imagine a Maserati owner being short of the cash needed to fix this, but let's not put people off making essential journeys before getting it fixed. After all, the wear has already happened of 10s of thousands of miles before the rumble is noticed.

What cause the rumble? As soon as the a/c is swiched on the a/c clutch engages and holds the pulley off the worn surfaces of the nose, the inner race is no longer being held tight against just one portion of the nose by the belt tension, hence the rumble.

What's the root cause? Seems to be a tolerance issue - the inner pulley bearing race isn't tight enough on the nose from new. Hence over time, with thermal expansion allowing the inner race to move, the nose gradually wears.

How do I know this? I had my old compressor sent back from Compressotech after they gave up on attempting to remanufacture it. I'd assumed all along that the bearing was at least semi-siezed. Actually it was almost perfect - a tiny amount of play and spinning freely - good as new. I spoke to Compresssortech at length and this type of failure is common. I've also examined the compressor from a Ferrari F599 - exactly the same part (ignoring part numbers!) - and at 7k miles the pulley was just loose enough to be removed by hand. It should require a puller.

 

[Kazzer]

Its back all fixed - compressor seized.

Between Richard and Mark at Carr's all sorted - many thanks to both for dealing with this for me.

Thanks for the advice on here - now to tackle the jukebox

 

[bigbob]

I got a new a/c compressor on mine recently under warranty. It had not seized but was getting noisy and the pully was moving about a little. Fit for purpose?

 

[allandwf]

There is something to that. Black being a typical example. Years ago black was rare, you had to pay extra, as it required extra or more attention to preperation, it was then perceived, by some, as being extra desirable.

 

[Felonious Crud]

Its back all fixed - compressor seized.

Between Richard and Mark at Carr's all sorted - many thanks to both for dealing with this for me.

Thanks for the advice on here - now to tackle the jukebox

Good news. Glad it's all fixed.