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Old 12th June 2019, 20:31   #11
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Originally Posted by SD1too
I would definitely not do that for the following reasons. In my experience, these 'O' rings do not normally require lubrication. The union is of similar construction to brake and high pressure oil lines and there is virtually zero risk that the 'O' ring will deform. If lubrication is used, the workshop manuals specify a smear of refrigerant oil. You do not want even the smallest amount of rubber grease entering your air conditioning system where it could cause a malfunction.

Simon
I don't know where that little nugget of information came from, but it's completely incorrect Simon

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Old 12th June 2019, 20:40   #12
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When I was planning on changing my condenser, my local friendly garage de- pressurised the system for me and lent me a bottle of the oil that they put into the system, or I think that's what it was, may be wrong. He said lube the o rings with it, and don't spill it cos it's extortionately expensive.

When I had done the work, he vacuum tested the system for leaks then refilled it for me. Perhaps I should have said his machine did, it the system fails the vacuum test it won't attempt to fill it.

He explained that leaking that gas into the atmosphere would get him a 1k fine, jeez!
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Old 12th June 2019, 21:03   #13
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When I was planning on changing my condenser, my local friendly garage de- pressurised the system for me and lent me a bottle of the oil that they put into the system. He said lube the o rings with it, and don't spill it cos it's extortionately expensive.

When I had done the work, he vacuum tested the system for leaks then refilled it for me. Perhaps I should have said his machine did, it the system fails the vacuum test it won't attempt to fill it.

He explained that leaking that gas into the atmosphere would get him a 1k fine, jeez!
Hmm, you were not given good advice Mike

PAG oil is extremely hygroscopic, much much more so than brake fluid, and it forms acid when moisture is absorbed.

This will cause leaks at the pipe unions to occur.

The PAG oil will damage lots of things, the A/C compressor included, if the moisture level exceeds 800 PPM, so the bottle of oil you were loaned will have been wrecked, it's to be hoped it wasn't used in the recharge

I don't play with small A/C systems in my line of work, but have an awful lot of experience of servicing refrigerant compressed air drying machinery, normally handling FAD of circa 600 CFM.........slightly more critical setup than your average car A/C

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Old 12th June 2019, 21:24   #14
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Originally Posted by SD1too View Post
If lubrication is used, the workshop manuals specify a smear of refrigerant oil.
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Originally Posted by marinabrian View Post
I don't know where that little nugget of information came from, but it's completely incorrect Simon
Workshop Manual (RAVE), Service Procedures, Air Conditioning, Condenser, Refit, 82-11:

"1. e. Lubricate new 'O' rings and threads of plug with clean refrigerant oil.
8. Lubricate new A/C pipe 'O' rings with clean refrigerant oil."


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Old 12th June 2019, 21:47   #15
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Workshop Manual (RAVE), Service Procedures, Air Conditioning, Condenser, Refit, 82-11:

"1. e. Lubricate new 'O' rings and threads of plug with clean refrigerant oil.
8. Lubricate new A/C pipe 'O' rings with clean refrigerant oil."


Simon
Polyalkylene Glycol (PAG) oil

PAG oil is a man-made lubricant that is used in R134a and R-1234yf A/C systems, although the two types of PAG oil are different. There are several viscosities of PAG oil used by vehicle and compressor manufacturers and using the wrong viscosity oil in a compressor may create abnormal compressor noise and possible premature internal component wear.

By its chemical structure PAG oil is hygroscopic, meaning it attracts and retains moisture which can come from the atmosphere or from the A/C system. PAG oil and moisture together are not a good combination as when they mix, it forms an acid, causing damage or failure to system related components.

This type of oil should never be used to lubricate O-rings, compressor shaft seals or refrigerant line joints as in time corrosion can set in, which may cause a refrigerant leak. If the corrosion becomes severe enough, joints and fittings can fuse together and may not be removable during a future service repair.

There are some guidelines to follow when using PAG oil to keep it as moisture-free as possible:

When repairing an A/C system where refrigerant components are being removed, immediately seal off component fittings to minimise atmospheric moisture from entering a component or the system.
When installing replacement parts, keep caps on the part, except when you’re performing an oil balance or are ready to install the part. This too will minimise exposure of the PAG oil to atmospheric moisture.
The moisture absorption rate of PAG oil can occur at a rapid pace. If a container of PAG oil was left open overnight, it must not be used as it will have absorbed too much moisture to be effective in an A/C system.
To keep moisture to a minimum, always reseal the container immediately after dispensing PAG lubricant from it. If it is not known whether a container of PAG lubricant has not been properly resealed, do not use it.
Pull a vacuum on the refrigerant system after it has been repaired. Follow proper refrigerant recovery and recharging procedures, which typically includes a minimum vacuum of 45 minutes, to remove any moisture that has entered the A/C system during its repair.
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Old 12th June 2019, 23:04   #16
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here's hoping my A/C does not fail on the NUK when we get the hot boiling weather later this year photo's say it all.


1st pic shows joints broken open.

2nd & 3rd close up of the O-rings

4th close up of old O-rings removed large black one seems damaged maybe by inserting the connection dry ?

5th the new O-rings

6th & 7th rubber grease added
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Old 13th June 2019, 08:07   #17
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... PAG oil is hygroscopic .... PAG oil and moisture together are not a good combination as when they mix, it forms an acid, causing damage or failure to system related components.
That's why there's a drier in the system containing dessicant.

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Old 13th June 2019, 14:53   #18
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I am not 100% sure what he gave me to lube the o rings.
It was a see through pale blue colour from what I remember.

They are an air con centre so I guess it was correct. Been ok for the last couple of years anyway.
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Old 14th June 2019, 11:30   #19
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Although too late for you now, Halfords offer a free check up which also includes testing your a/c gas. I know, mine had zero gas in it!
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Old 16th June 2019, 21:32   #20
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Cheers for all the replies everyone - it was an interesting read.


I found a bit of time today in a busy weekend to get the radiator etc swapped around. I'm really happy because the work went well and quite a few loose ends have been tied up with one relatively easy bit of spannering.


Here's the start of the work, with the undertray droped down, ready to get the bumper off - note the tape to protect the wing:


IMAG1610 on Flickr


Most of the panels removed and ready to go. You can see that the fan has a chunk missing from the accident that also wrote-off the intercooler and radiator:



IMAG1613 on Flickr


The old intercooler is obviously knackered - plenty of oil on the left as you look at it here:


IMAG1612 on Flickr



You can see here that I had double trouble - a leak on the Driver's side, and also the twist on the intercooler meant that it would never seal properly on the passenger side:


IMAG1611 on Flickr


Here's a pretty badly-taken picture of everything removed, ready to start reassembly with the new unit:


IMAG1614 on Flickr


I got new Condenser o-rings from DMGRS which arrived over night so it's been re-assenbled with those (I used the tiniest bit of 10w-40 to lubricate them) and also viton o-rings in the intercooler tube.


It's all back together now, except the bumper, because while I've got it off, I'm going to use a Turtle-wax headlight restoration kit to sort them out, too.


By the time it's complete, this bit of work (including the new rear bumper and bonnet) will have rectified:

-Dented bonnet with lacquer lifting replaced
-Dented and badly-repaired rear bumper replaced
-Parking sensors now work
-Cooling fan now works (resistor replaced)
-Replaced Coolant
-Intercooler not leaking
-AC Condensor replaced with new seals
-Wiring tidied up
-Headlights refurbished
-AC re-gassed

Not bad for a few hours work and about £300 in parts and service items.

Last edited by Tourist; 16th June 2019 at 21:37.. Reason: speeling errrror
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