Hi + aircon pump exploded!

[HannahJ]

Hi all,

I'm new here and a relatively new Fiesta owner. I've had it about 6 months, it's a 2011 Zetec and only about 42,500 miles on the clock so lightly used before I got it.

The aircon was barely cold, so I had it regassed last week - it didn't seem much colder after but the garage guy said his Ford also has feeble aircon.

On Friday afternoon the pump exploded while driving on a main road...

Has anyone encountered this before?

What I know:

• When they regassed it, very little old gas came out.
• The breakdown guy said the wrong gas/overgassing could cause it to explode - garage says they wouldn't have done either (I trust them, came highly recommended etc)
• Garage guy said if the pump had been at low pressure for a while (as basically empty), this might have had an adverse effect.

Poor little car!

Any ideas?

Cheers,

Hannah

 

[Luke4efc]

Actually the garage could get done for what they did. Refrigerant is highly damaging to the environment if released (toxic), so anyone with a licence to gas air con units is supposed to check for leaks before gassing. The fact there was little gas in the system tells me there is a leak, refrigerant doesn't just disappear from a closed system.

If the pump hasn't been used for a while then just starting the AC compressor might have just disturbed something and caused it to fail. Overgassing, or gassing incorrectly can cause too much liquid to be in the compressor (or pump, whatever you want to call it)(everything feeding the compressor should be a vapour), and could have hydraulically locked meaning the piston couldn't go anywhere and "exploded". As for wrong refrigerant, I very much doubt it. R134-a is the most common used in any fridge (or air con, same principle) for a good while now, and nothing different is ever really used on cars as most are banned. R22 has been outlawed by the EU for years. 

As you said, it could have also been caused by running dry, but make sure the garage checks for leaks before re-gassing it after you get the compressor changed, they should know that anyway though.

Source: I'm learning for city and guilds in refrigeration.

[MJNewton]

It is also worth noting that the gas is a mixture of refrigerant and lubricant. The loss of the latter will eventually lead to seals drying out and, as perhaps might be the case here, failure of the compressor. Furthermore, lack of pressure can lead to air being drawn in which, given its moisture content, can then lead to corrosion if the dryer is unable to absorb it.

[isetta]

I think if this happened to me I would just do without the aircon. Is it worth spending the amount of money needed to fix it. I know it's nice to have aircon, but many years ago 99% of cars did not have it and we all survived.

[HannahJ]

Thanks all.

Sounds like it was overgassed then - though apparently that's very difficult as they know the correct measurements etc.

The aircon had been on before being regassed, just wasn't cold (obviously as no gas). So seems unlikely anything would have seized up. If there was a leak, wouldn't that have prevented it exploding?

Interesting about the lubricant and seals - I'll investigate that further.

[David73]

13 hours ago, isetta said:

I think if this happened to me I would just do without the aircon. Is it worth spending the amount of money needed to fix it. I know it's nice to have aircon, but many years ago 99% of cars did not have it and we all survived.

Agreed. A pity manufacturers don't offer it as a delete option. It is low in benefit for high cost. If it's used permanently it burns fuel and gets smelly, if it's not used it doesn't work for the three days a year when it might be useful. (I don't accept any help it gives with demisting as a big deal. It doesn't work below 3C anyway.)

[isetta]

"(I don't accept any help it gives with demisting as a big deal. It doesn't work below 3C anyway.) ".     and if the car has a quickclear windscreen there is even less argument about it being good for demisting

[MJNewton]

3 hours ago, HannahJ said:

Sounds like it was overgassed then - though apparently that's very difficult as they know the correct measurements etc.

I am not sure how you reached that conclusion from the discussion, particularly as you say it is very difficult to do given the method used to (re)fill these systems. Furthermore, there are both low and high pressure cut-outs on an air conditioning system and so the fact it was allowed to run at all suggests to be that it was within spec pressure wise.

[HannahJ]

52 minutes ago, MJNewton said:

I am not sure how you reached that conclusion from the discussion, particularly as you say it is very difficult to do given the method used to (re)fill these systems. Furthermore, there are both low and high pressure cut-outs on an air conditioning system and so the fact it was allowed to run at all suggests to be that it was within spec pressure wise.

I was unclear - I meant that the garage advised me they wouldn't have overgassed it as they know the correct amount to put in.

Good point about the cut-outs - suggests no leak. Still no idea what could cause it to explode then!

[MJNewton]

There must have been a leak otherwise it wouldn't have needed regassing. The leak prior to refilling could have been slight enough that it was unable to hold high/working pressure yet still not fall below the low pressure threshold of operation hence the poor performance. When leaks are suspected but not identified it is common practice for a fluorescent dye to be added to the new gas; a UV lamp can then be used to help determine where it is leaking out from.

Given it was the compressor that failed I think the fault lies (or lay!) within it - possibly due to lack of lubrication as discussed.

[Ryan_Tango]

20 hours ago, isetta said:

I think if this happened to me I would just do without the aircon. Is it worth spending the amount of money needed to fix it. I know it's nice to have aircon, but many years ago 99% of cars did not have it and we all survived.

To fix it depends in the UK not really but abroad yeah, I've had no aircon for 2 years as it's empty (I think) getting it regassed and serviced at Ford next month, I had to do without it going Ford Fair last year and I really wish I had it as it was absolutely awful windows down, but for the majority of the time doing without would be fine.

[GaryPL]

5 hours ago, HannahJ said:

The aircon had been on before being regassed, just wasn't cold (obviously as no gas). So seems unlikely anything would have seized up.

Quite the opposite actually. The air-con compressor is a self lubricating part and must be running to be lubricated.  Just like a turbo.

If there's no gas and you are running the system, it will seize.  Probably with a lot of heat too.

[Luke4efc]

Whenever I have thoroughly tested for leaks, we use nitrogen and make sure it holds pressure, therefore any leaks doesn't harm anything. We then use leak detection spray (just soapy water) to see any bubbles indicating a nitrogen leak. However I have never re-gassed anything on a car, just normal AC units. 

As you said, I doubt the garage would've over/under gassed it. The refrigerant gets weighed in.

2 hours ago, HannahJ said:

Good point about the cut-outs - suggests no leak. Still no idea what could cause it to explode then!

As I said in my first post, refrigerant doesn't just vanish. The AC system must be closed so that the refrigerant cant escape into the atmosphere as it's so damaging (greenhouse gasses etc.). The compressor has probably siezed as there was no lubrication as there was no refrigerant in the system due to a leak, however small it might be. Chances are you tested it just after they gassed it, therefore most of it still in the system and holding pressure so turned on. Give it a few weeks and it will be even weaker at removing heat than it is now.

[HannahJ]

1 hour ago, Luke4efc said:

Whenever I have thoroughly tested for leaks, we use nitrogen and make sure it holds pressure, therefore any leaks doesn't harm anything. We then use leak detection spray (just soapy water) to see any bubbles indicating a nitrogen leak. However I have never re-gassed anything on a car, just normal AC units. 

As you said, I doubt the garage would've over/under gassed it. The refrigerant gets weighed in.

As I said in my first post, refrigerant doesn't just vanish. The AC system must be closed so that the refrigerant cant escape into the atmosphere as it's so damaging (greenhouse gasses etc.). The compressor has probably siezed as there was no lubrication as there was no refrigerant in the system due to a leak, however small it might be. Chances are you tested it just after they gassed it, therefore most of it still in the system and holding pressure so turned on. Give it a few weeks and it will be even weaker at removing heat than it is now.

Good points - problem is that it *did* turn on before they regassed it (so presumably had enough pressure), and did turn on shortly afterwards (though wasn't much colder). The issue now is that there is very little left of the pump at all! All very helpful, thanks.

[Luke4efc]

Yeah, it's probably not worth fussing too much over now. Just make sure there is no liquids of any kind in the system, check for leaks, replace the pump and regass. Job done.

[HannahJ]

4 hours ago, Luke4efc said:

Yeah, it's probably not worth fussing too much over now. Just make sure there is no liquids of any kind in the system, check for leaks, replace the pump and regass. Job done.

Thanks Luke, what I'm going to do. However if it turns out to have exploded because of something the garage didn't check, I'm not paying for it!

[HannahJ]

One new pump later and my aircon is icy. Looks like the compressor had been seized for some time - the car came from Scotland so it's possible the aircon wasn't used much, hence the lack of gas (may have very slowly seeped out). Slightly annoyed the garage I bought it from hadn't checked the aircon before I picked it up, though I forgot to check it myself. I now have the old pump to display on the wall! Thanks all for the advice, I now know more about air conditioning than I ever dreamed I would.

[MJNewton]

Great news!

[Eric Bloodaxe]

Don't think we have many members who will be looking for air con service in Singapore, tbh.