AC PAG Oil run out - compressor damage possible?

[DRJ]

Summer's coming (!) and the local ATS next to Tesco was offering AC Regassing for £35 so since my AC had seemed to be low on cooling availability during a hot spell a week or two ago and it's been feeling a bit down since last year I thought I'd take it in.

 

The car's 2007 so eight years old. I bought it four years ago and the AC hasn't been checked since though it may of course have been checked before I bought it. In fact driving down there - on a relatively cool morning - I had the AC on and it seemed to be cooling nicely so I did mention that when dropping it off.

 

Anyway it turned out that the gas was fine - the printout's reproduced below - but the "oil" was empty, and they explained that was causing the low performance since the "pump" wasn't being lubricated. I've subsequently discovered that there's a supply of oil in the AC system - called PAG Oil - something I was unaware of until Googling today.

 

So, has the fact that the oil had run out done any potential short- or long-term damage to the compressor? I hadn't heard any unusual noises and it was clearly still operating since it was cooling.

 

As far as I am aware checking of the PAG Oil level is not covered by a service (at least there's no reference to it) and it clearly isn't something that would throw up a warning light - so is this a problem just waiting to happen? Should it not be more known about and checked at a service?

 

Full printout - anything else to comment on?:

 

RECYCLING

R134a

g.    565 ref.

g.        0 oil.

 

A/C SYSTEM VACUUM.

min.     20

 mB.    27

 

OIL INJECTION

g.     10

 

UV INJECTION

g.      5

 

A/C CHARGING.

R134a

g.     550 ref.

 

EDIT - I should add that driving back home it did seem a little cooler but not much difference!

Edited 22 May, 2015 by DRJ

[Phil-E]

The oil is put in the system with the refrigerant.

 

Normally when you get an A/C service they suck everything out then pump the correct weight of coolant and oil into the system.

 

It may be that when it last had a service the wrong amount of oil was put in (or none at all!).

 

Hopefully the pump will be fine... it could have damaged it but no way of telling really.

 

Phil

[DRJ]

Oh I see - like a 2 stroke engine, oil mixed into the petrol. I somehow assumed there was a separate reservoir.

[Phil-E]

Oh I see - like a 2 stroke engine, oil mixed into the petrol. I somehow assumed there was a separate reservoir.

 

That's right. It's just mixed in with the refrigerant and is pumped round with that so it lubricates the whole system.

 

If there's no funny noises then you should be OK. A failing A/C pump usually whines slightly following the engine revs.

 

Phil

[vr6 south]

I hope it's not the pump as they are serious money to buy new.

Edited 22 May, 2015 by vr6 south

[Dave89]

Should be able to pickup a new pump for circa £200 if needed

There's loads of breakers on eBay though so you could always try a used one.

[sepulchrave]

Full printout - anything else to comment on?:

 

RECYCLING

R134a

g.    565 ref.

g.        0 oil.

 

A/C SYSTEM VACUUM.

min.     20

 mB.    27

 

OIL INJECTION

g.     10

 

UV INJECTION

g.      5

 

A/C CHARGING.

R134a

g.     550 ref.

 

EDIT - I should add that driving back home it did seem a little cooler but not much difference!

 

They took out more gas than they put back in, as stated it's not possible for you have had no oil in it since the system would lose all its gas first if it had a leak.

 

Operator error, it's ATS remember, they fit tyres and exhausts.

[DRJ]

The way they explained it was that the oil was gradually used up - as it would be in an engine. I realise that there was no leak, but conversely would the AC have been running at least four years (if not more) if there was no oil in it when I bought it?

 

ATS fit tyres, exhausts and batteries(*), do MoTs, servicing and brakes - and do AC recharging. I don't see why you should be criticising them so, suggesting they're just tyre fitters. .

 

 

* - as usual with all online battery replacement specialists they quote for the WRONG battery (0906 instead of 027) - but that applies as I've said to everyone!

[sepulchrave]

I don't see why you should be criticising them so, suggesting they're just tyre fitters. .

 

Because the AC machine operator has made an obvious mistake, why else?

 

How the hell is the oil going to 'get used up', have the PAG oil pixies been drinking it?

 

Even AC systems which have leaked all their gas out still have oil in them.

 

You asked, I answered, you don't like the answer then suit yourself. I'm out.

[SKYHAWK]

Summer's coming (!) and the local ATS next to Tesco was offering AC Regassing for £35 so since my AC had seemed to be low on cooling availability during a hot spell a week or two ago and it's been feeling a bit down since last year I thought I'd take it in.

 

The car's 2007 so eight years old. I bought it four years ago and the AC hasn't been checked since though it may of course have been checked before I bought it. In fact driving down there - on a relatively cool morning - I had the AC on and it seemed to be cooling nicely so I did mention that when dropping it off.

 

Anyway it turned out that the gas was fine - the printout's reproduced below - but the "oil" was empty, and they explained that was causing the low performance since the "pump" wasn't being lubricated. I've subsequently discovered that there's a supply of oil in the AC system - called PAG Oil - something I was unaware of until Googling today.

 

So, has the fact that the oil had run out done any potential short- or long-term damage to the compressor? I hadn't heard any unusual noises and it was clearly still operating since it was cooling.

 

As far as I am aware checking of the PAG Oil level is not covered by a service (at least there's no reference to it) and it clearly isn't something that would throw up a warning light - so is this a problem just waiting to happen? Should it not be more known about and checked at a service?

 

Full printout - anything else to comment on?:

 

RECYCLING

R134a

g.    565 ref.

g.        0 oil.

 

A/C SYSTEM VACUUM.

min.     20

 mB.    27

 

OIL INJECTION

g.     10

 

UV INJECTION

g.      5

 

A/C CHARGING.

R134a

g.     550 ref.

 

EDIT - I should add that driving back home it did seem a little cooler but not much difference!

I got a pump if needed pm me

[DRJ]

Because the AC machine operator has made an obvious mistake, why else?

 

How the hell is the oil going to 'get used up', have the PAG oil pixies been drinking it?

 

Even AC systems which have leaked all their gas out still have oil in them.

 

You asked, I answered, you don't like the answer then suit yourself. I'm out.

 

 

Sorry - but I totally fail to understand the reason for your animosity - and find it quite disturbing if I'm honest.

 

What do you think the "mistake" made by ATS is? Are you saying their machinery is defective? Or are you saying there is some sort of operator error?

 

"How the hell is the oil going to 'get used up', have the PAG oil pixies been drinking it?" - Why can't oil be used up? Seems a perfectly logical thing to happen.

 

"Even AC systems which have leaked all their gas out still have oil in them." - I don't understand.

 

"You asked, I answered, you don't like the answer then suit yourself. I'm out." - I don't understand.

[DRJ]

I got a pump if needed pm me

 

Thanks - but sorry - I don't know whether I need one or not - the AC has been working for 4 years at least, though it didn't seem quite as cool as it did before I took it into ATS - hence the reason for calling in there yesterday. The AC is still working, though I haven't tried it "in earnest" yet (i.e. on a hot day). How will I know I if I need a pump?

 

I'm beginning to regret ever having related my experience when it seems people can't explain properly how it works and whether there is any risk.

[unsolicited]

The slightly grumpy poster was right btw. The oil exists in liquid form inside the pump/filter dryer, and the other aircon components. When you evacuate the gas some oil usually comes out but not by any means all of the oil in the system. It's impossible for the machine to know how much oil is left in the system. The machine measures what it removed, then adds back the same amount of oil (or a little more).

 

It looks like the machine was faulty as there should always be some oil in the extracted gas....

 

But the operator is utterly wrong to state you have "no oil" in the system. He (and his machine) cannot know that.

Edited 25 May, 2015 by unsolicited

[DRJ]

Thank you. I'm relatively assured that the system's fine.

[DRJ]

Whatever the situation re oil being in the system pre-check or not, it's now running noticeably cooler so what ATS did it's improved the cooling performance.