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Discussion Starter · #1 ·
Driving out of the petrol station this evening and there was a very loud hissing noise and clouds of smoke rolled out from under the bonnet.

Turned everything off. Opened the bonnet. Radiator fan, turbo pipes, the whole right side of the engine was covered in oil. Rubbed a finger in it.. not black so not engine oil, not pink so not transmission fluid. Can't be steering rack fluid or brake fluid..

Then I notice the plug on the back of the air con compressor is missing... and its direclty inline with the pipes that are soaked in oil. So its the lubricating fluid from my a/c system and the smoke must have been the refridgerant.

System (compressor and new gas) was replaced last autumn so I'm not a happy chappy.. will talk to garage tomorrow.

Is this a normal thing to happen or is it indicative of a major problem in which case I'll leave the compresssor clutch disconnected and forget having a/c.

Steve
 

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Assuming yours is like my '94 car, the compressor is fitted with a rupture disc as a last line of defence when something goes wrong. I think it's there to ensure that the cooling coils in the heater box are not the weak point, as a failure here would fill the car with gas and oil.

The disc has ruptured because the pressure in the system got far too high. Assuming that it is not something weird like too much refrigerant was put in when it was filled, the likely reason is because the fan was not switching on to cool (and hence liquify) the refrigerant. This seems logical as the failure happened when the car was not moving.

When in normal motion, there is enough air velocity through the rad to cool the gas. However, when you stop, the compressor continues to compress the gas, but there is no cooling. As the pressure increases, a pressure switch should turn on the cooling fan on low speed, which provides sufficient air velocity. If the fan does not start, the pressure builds up, as does the temperature of the compressor and its output pipework. There is a thermal cut out on the compressor body as an additional safeguard before the rupture disc blows.

Assuming that nothing really strange has been going on, I would put money on it being a failure in the wiring loom for the pressure switch. It is a dual (low & high) pressure switch situated behind the right hand headlight. I assume the rupture disc is cheap and easy to replace.

I had the same problem, but the aircon expert spotted it and we fixed the wiring.

See this missive for more information
 

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Mark wrote:
"....assuming that it is not something weird like too much refrigerant was put in when it was filled ..."

It may be wierd but it does happen! This is precisely what happened to me when the system had to be refilled following a minor accident - the system was over-filled and made such a noise when it clutched-in (and had such a marked effect on the engine when it clutched-in) that I stopped using it until I could get it seen to. The diagnosis was that it had been grossly over-filled. Fortunately it didn't explode in the way that yours did.

Regards
Paul Whittle
 

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Discussion Starter · #4 ·
garage who did the new compressor say that its most likely a cooling failure. The rad fan is still working fine and doing all its usual things like running after the engine is switched off so I guess its the switch/wiring for the a/c thats gone wrong.

Its in for a transmission fluid change next wednesday so hes going to look at it then. If its a major problem (like the condenser jet being blocked) then I've told him to forget it and I'll run without.

I've disconnected the clutch power line and set the ACC to come on in ECON mode so its safe to drive.

Wish in a way that I'd had a video camera to film it... it was pretty impressive.

What was depressing is that not one person wh owas stuck behind us on the roundabout even checked to see if we needed help.. they just drove over the pavement and left us alone even though they'd seen the clouds of "smoke"

Steve
 

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Discussion Starter · #5 ·
OK garage had a look at it after doing an transmission oil change (nice smooth shift up and down now and its silent! ).

He says there is nothing coming out of the control unit. So I guess this points to a failure in the relay box. I suspect I'm going to grub round and check a couple of things this coming weekend... yet another weekend working on an engine

Steve
 
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