Condenser explosion

mikem

Junior Member
Messages
240
Last wednesday (hottest day of the year) I picked up my 4200cc from Giallo. Having had the forum discs and new pads fitted, I was looking forward to setting off to Italy for my summer holiday this coming weekend.

However I got about a mile from Giallo when there was a loud explosive bang. The car lost power even though the engine was still running and the power steering stopped working. I was on a very busy T junction in the evening rush hour so there were a lot of unhappy drivers. So I telephoned Matt at Giallo and he sent Ches to come and investigate.

When Ches came he started the car and it worked perfectly so he drove it back to the garage for a hook up to the computer. Everything appeared completely normal. However the air con. had stopped working, the conclusion being that the compressor had failed. So Matt very kindly lent me his personal car to get home.

A new compressor was ordered but when Matt tried to fit yesterday. He discovered that the compressor was o.k. but the condenser had a one inch square hole in it. Matt explained that he had never seen or heard of any thing like it ever happening before. Also that advice he had been given was that condensers have been tested to 20 bar, so it must have been some incredible force to remove a 1" square chunk of metal from it.

So far the cause of this is a mystery.

Has anyone else had a similar incident and was the cause ever discovered?
 

safrane

Member
Messages
16,749
The A/C system seems to be very fragile on Maserati, compressors seem to be a common failure point, but not heard or read of this issue before.

Im my case it was the compressor's clutch that disinterested causing it to melt and eventually sieze
 

conaero

Forum Owner
Messages
34,594
Never seen that, was the impact from behind in the engine bay or through the front?

I am guessing it just simply failed. Its quite a job to replace, front bumper off I am afraid.
 

StuartW

Member
Messages
9,306
Might be worth considering a radiator change while you are in there. If it's the original rad, it could well have it's best days behind it and it's not much extra labour to attend to once the AC condensor is off
 

mikem

Junior Member
Messages
240
The A/C system seems to be very fragile on Maserati, compressors seem to be a common failure point, but not heard or read of this issue before.



Im my case it was the compressor's clutch that disinterested causing it to melt and eventually sieze

I remember reading your thread and if I remember correctly didn't it occur somewhere in France?

It is because of your travails that we are seriously considering whether to take the risk of driving down to Italy. Assuming Matt can fit another condenser and discover the cause of the failure in time.
 

safrane

Member
Messages
16,749
It was on our trip and occurred on the penultimate day.

We have successfully compleated five other euro tours without issue in our Maseeatis, so it would not put us off... but was a bummer when it happened.

Just take out Euro cover.
 

Navcorr

Member
Messages
3,839
A square hole sounds odd - do these condensers have a blow-out disc? If the compressor is increasing pressure without regulation (sensor failure?) a rupture disk would prevent damaging the entire AC system.
 

mikem

Junior Member
Messages
240
Never seen that, was the impact from behind in the engine bay or through the front?

I am guessing it just simply failed. Its quite a job to replace, front bumper off I am afraid.

Matt did tell me which end it exloded from,but I forgot when he explained it wasn't possible to replace with a new one prior to our departure. So he has found a second hand one for now. We are hoping that will do the trick. Fingers crossed it is ready for friday.
 

mikem

Junior Member
Messages
240
A square hole sounds odd - do these condensers have a blow-out disc? If the compressor is increasing pressure without regulation (sensor failure?) a rupture disk would prevent damaging the entire AC system.

Interesting possibility. I haven't actually seen the offending article so it may be just a case of Matt giving a rough approximation.
 

allandwf

Member
Messages
10,958
I would have thought the compressor would have the safety blow off device to prevent over pressurisation as it supplies the pressure. It may be faulty.
 

CatmanV2

Member
Messages
48,557
I would have thought the compressor would have the safety blow off device to prevent over pressurisation as it supplies the pressure. It may be faulty.

I can't really get my head round a car driven compressor being able to deliver that much pressure anyway

C
 

safrane

Member
Messages
16,749
A failed sensor sound plausible but as C says, thats some pressure to blow a pipe out from the inside...I would have thought the joints would give out first... unless there is a weak point (designed or not)
 

Navcorr

Member
Messages
3,839
The condenser is rated to 20 bar which isn't so high. But any closed system can easily over pressurise - if that is what has happened. An explosive failure would suggest so. Have Giallo said where the hole is?
 

Danny

Member
Messages
442
I had (more or less) something similar. My pressure switch threw an error, I bypassed it for diagnostic purposes, but then I forgot to remove the bypass.... As a result the system built-up so much pressure (within just a couple of minutes) that the weakest link failed, which in my case was one of the AC hoses. So, you may want to have a look at the correct functioning of your pressure switch.
 

Zep

Moderator
Messages
9,110
20 bar is good enough for a 70 degree condensing temperature so not much to worry about there in terms of operating pressure. The theory of the failed pressure switch is bang on in my view.

Because car A/C compressors run at engine speed, they need to be effective at idle and then not too effective at 7000 rpm. This means capacity control which is the high pressure switch and a bypass valve in the compressor body to bleed off the pressure back to the inlet of the compressor. If this stops working the pressure at the outlet spikes and something will give. There is no legal requirement to have a pressure relief device in a car A/C system so it finds the weakest spot and you get an interesting bang.
 

conaero

Forum Owner
Messages
34,594
I had a failed pressure switch in the Alfa GT with did the opposite and stopped the pump engaging so they are a common failure.

Fitted it and the system fired right up full chill.

The GT one was about £20 off eBay, I suspect the Maser one is highly likely to be the same. You dont need to degas the system to fit it either...a bit lat in your case.

Here it is:

http://www.ebay.co.uk/itm/AIR-CON-C...ROMEO-147-159-GIULIETTA-GT-MITO-/252043791184
 

mikem

Junior Member
Messages
240
The condenser is rated to 20 bar which isn't so high. But any closed system can easily over pressurise - if that is what has happened. An explosive failure would suggest so. Have Giallo said where the hole is?

Matthew of Giallo did tell me where the hole is but I can't remember. However he did ring me later to tell me that he had replaced the condensor and that now the old one was on the bench he could see far more extensive damage to the extent of near disintegration.

I am hoping to pick the car up today, so may have the opportunity to see the damage.
 

Zep

Moderator
Messages
9,110
Matt's right, I had looked at the parts list and there is only one pressure switch in the system - which will be a low pressure / loss of charge switch which prevents the compressor running when there is not enough gas in the system. Looking at my old GS compressor there is only one electrical connection which is for the clutch. This means that the high pressure limit / capacity control is done inside the compressor by a spring loaded valve. If the condenser damage was caused by mechanical damage then all will be good, if the pressure limiting in the compressor has failed it will need a new comp. I'll keep my fingers crossed for you!

I had a failed pressure switch in the Alfa GT with did the opposite and stopped the pump engaging so they are a common failure.

Fitted it and the system fired right up full chill.

The GT one was about £20 off eBay, I suspect the Maser one is highly likely to be the same. You dont need to degas the system to fit it either...a bit lat in your case.

Here it is:

http://www.ebay.co.uk/itm/AIR-CON-C...ROMEO-147-159-GIULIETTA-GT-MITO-/252043791184
 

mikem

Junior Member
Messages
240
Matt's right, I had looked at the parts list and there is only one pressure switch in the system - which will be a low pressure / loss of charge switch which prevents the compressor running when there is not enough gas in the system. Looking at my old GS compressor there is only one electrical connection which is for the clutch. This means that the high pressure limit / capacity control is done inside the compressor by a spring loaded valve. If the condenser damage was caused by mechanical damage then all will be good, if the pressure limiting in the compressor has failed it will need a new comp. I'll keep my fingers crossed for you!

When I spoke to Giallo this afternoon concurred that there is not a pressure relief valve, solely a pressure switch. But Matthew is reasonably confident that the compressor is O.K.
 

markp4200

Member
Messages
331
Last wednesday (hottest day of the year) I picked up my 4200cc from Giallo. Having had the forum discs and new pads fitted, I was looking forward to setting off to Italy for my summer holiday this coming weekend.
Complete change of tack but are these the new discs from batch 3? If so how did you get yours? If not then I still wait.