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a/c u/s advice sought

1K views 34 replies 8 participants last post by  RB2004 
#1 ·
Hi All, on the hottest day of the year my a/c didn't work ???? in fact, the symptoms are more or less the same as this thread:
http://www.talkford.com/community/topic/291842-ac-starts-and-stops-continuously/?view=getnewpost
with the compressor starting and stopping continually. Also, the twin cooling fans don't run. The condenser has been shedding those aluminium fin things for years...how easy is it to change or should I take it somewhere to get the gas contained-if there's any left in the system. What's the easiest way to test those fans, and should they run as soon as the a/c gets turned on? How easy is it to replace that condenser. Thanks for all ideas. RB2004, don't suppose you cover Leicester by any chance? ????
 
#2 · (Edited by Moderator)
Took my sons (new to him) 51 plate VW polo ( I know!) to my AC guy yesterday as we have had the car a week and I was not happy with the output from it, very noticeable when you are sat in a navy blue car in 32'C traffic!
Anyway he connected it up and said that it only had just over 50% of the amount of gas it should have and this is why it is struggling to give any meaningful output, he said but this was a Good sign and showed that there is not a leak of any importance otherwise it would have No gas at all. So after putting in the correct amount (550g) it is working fine and made an instant difference. When I asked where by chance the lost gas could have gone due to no leak he said that the AC system is the same as a domestic fridge and if you carted it around for 20000 miles plus would you not expect it to fail slightly? I think he means that there are lots of dis-similar connections ie rubber to metal crimps,metal to metal glands and screwed connections that all can be susceptible to vibrations and disturbance and over time made not be 100% but this may be enough for a slight leak over a long time!
Any more knowledgable input would be very welcome to explain this situation further,

Paul m.
 
#3 ·
Reading some of RB2004's posts, he writes about salt corrosion causing pinprick holes in pipework, also the condenser, if it's got crumbling fins then odds are it's also gone leaky too, but due to cost of repairs people just want a quick fix so just opt for a recharge.
 
#4 ·
Reading some of RB2004's posts, he writes about salt corrosion causing pinprick holes in pipework, also the condenser, if it's got crumbling fins then odds are it's also gone leaky too, but due to cost of repairs people just want a quick fix so just opt for a recharge.
From experience, road salt corrosion seems to be the biggest cause of condenser failure along with bad design.

If leaves and things get trapped between a condenser and another item like an intercooler or a fan then they usually fail behind the intercooler or fan, because the leaves and road dirt like soil etc hold moisture like a sponge. This is why condensers are always failing on the citroens and Peugeots because they all share a pretty common design of front mounted fan assembly.

You also tend to find condensers failing in nooks and crannies where water will settle and find its way into.

Like some condensers have on the vertical tubes either side, caps soldered on top and bottom to seal the ends.

Water will tend to sit on the edge of the cap as it forms a kind of ledge and work its way into the joint... And then it starts leaking, another favourite is drier caps when they are built into condenser.

On the mk1/2 galaxy the condenser themselves last well.. However there is a rubber cap over the drier cap and of course water gets into there and works its way into the gap around the cap, corrodes the aluminium, the corroded surface is them no longer flat, and the converted powdery material swells up between seal and sealing surface then seal no longer works and it leaks.

The water on its own isn't so much of a problem if it was pure, but it's not and they shove road salt on the roads in winter and I came to conclusion it was the road salt because I know salt does have an effect in corroding aluminium under certain circumstances and I noticed a pattern where vehicles which were near the sea, or from the north of the country were in worse condition than vehicles from the south... Some vehicles also which I don't normally see problems with condensers on I was also seeing on their 2nd at least condenser whereas normally I don't see any requiring replacement.

For example many vw golf V out factory, earlier ones anyway, had black painted condensers so they are instantly recognisable.

I don't change these hardly at all, they are that reliable.

But then every now and again you will come out to one which has an unpainted condenser fitted, so you know it's not an original, but on top of that despite being a replacement does not look in very good condition and when I ask usually the answer is vehicle has either come from a seaside location or north of country.

Interestingly will also find a lot of Volvos have steel pipes and not typical aluminium. They are actually a good example Volvo of the steel for a reason.

Because some Volvos are based on a mk2 focus... Under bonnet looks 90% similar.

As a result some of the Aircon pipes are identical, like the one from the drier to the bulkhead. And drier to compressor.

However on a focus those pipes are alluminium, on a Volvo they are steel... But they look like a high chance of interchangeability.

So why does Volvo use steel and ford use aluminium? Only link I can think of is corrosion resistance, because in Sweden they have a lot of road salt.

Because here in the UK condensers are the plague of air conditioning systems, but I'm told in hotter countries and places like Florida and California condensers very rarely fail.

You also tend to find that very rarely condensers fail from stone impacts, despite it the most commonly given reason.

When you examine the failure areas closer you find the alluminium has gone slightly white and powdery often. Unless it's covered up by oil from the a/c system.

The White powdery material is alluminium oxide. The metal has converted from alluminium to an oxide... And in doing so the metal becomes porous, sometimes in such a way that it lets the gas escape but not the oils and uv even... And that's why some leak in weeks, months or years.

If it was a pin hole it wouldn't last a day or 2.

Certainly if it has crumbling fins that condenser is now rotten, the crumbling material is no longer solid metal and as a result will more than likely leak over a period of time.

Not only that, loose too many fins and condenser will fail to work properly.

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#5 ·
Thanks for that RB, very interesting observations and stuff....wonder whether anyone makes an aftermarket condenser that's painted black to cut down the corrosion?

Took the car for it's very first a/c service...I never normally switched it on, having a sunroof, but I've had it 10 years and it's always worked up until the other day. Anyway, I now know I should use it occasionally due to the oil in the system needing to circulate and stop the seals from drying out (apparently) Also, I need to investigate a resistor pack on the cooling fans, as they're only coming on full speed.
 
#6 ·
A domestic fridge though it runs a lot has a good deal going for it that a car a/c doesnt. compressor directly driven by motor inside hermetically sealed enclosure for one, and living in a relatively stable environment for another.

I think the advice about running the ac occasionally even when the weather is cool is in the handbook for most cars, for exactly the reasons you give.

RB2004 is the man to comment on this, but often there are high as well as low pressure trips. lack of airflow can be a cause....
 
#7 ·
Here's the dirty little secret about vehicle Aircon.

Fridges, hermetically sealed compressor

Steel / copper brazed pipework.

It's a 100% sealed system... So unless it develops a leak it doesn't require refilling.

Vehicle systems, compressor shaft seal

Rubber hoses, with crimped joints.

Those are the only 2 places a vehicle will leak always.

However, here's the truth and reality of it.

If the system is used frequently so that the compressor shaft seal remains lubricated.

Then vehicles should easily go 7-10+ years between refils if completely 100% leak free.

I know this because every now and again I come across vehicles which have lasted.

I have 1 customer with a Ford Focus, it's a 2001 vehicle... And it still blows cold and has never been regassed in 15 years.

So if 1 vehicle is capable of holding gas for that long, then many others should do also.

However, I am increasingly seeing vehicles under 5 years old being presented for recharge.

This year even had a few owners with vehicles under warranty wanting to book a recharge... A peugeot 308, Porsche Panamera, Nissan qashqai, and a van... Can't remember what it was now.

But not only was they using the new 1234yf gas which I don't keep yet anyway but those were 2 year old vehicles and people was asking about a regas!

Funny thing is dealers mostly say Aircon should be recharged every 2 years!

Well in doing so you don't see it leak because if it leaks 50% every 2 years it's then refilled again.

This is not normal and not right.

But problem is, you then end up with an argument where 70% of vehicles presented for recharge have a leak... Even if it's a slow one where it lasts 3 years it's still a leak and often you can't see any evidence of a leak that slow.

So technically rather than regassing, the systems should be overhauled first to rectify the leak... Practically speaking though I don't know of hardly anybody customer wise who would entertain that idea.

I've been out to several this year, system practically empty, big black oil stain on condenser. Holds pressure, vacuums down fine.

Tell customer you believe it has a slow leak, they tell you to proceed anyway.

I'm sure some of them leak out, but I never hear from them again usually, maybe they don't want to be told "I told you so" or too embarrassed because they wanted to believe I was making up work and they told me to proceed anyway then turned out I was right.... No idea.

But I must be doing something right lol.

Past 2 days I have had so many calls i haven't had time to return any and nowhere to put them till next week in the book now. Rectangle Smile Vehicle registration plate Gesture Finger


I need somebody to answer phone for me really, I'm too busy during the day and get back gone 9pm and it's too late then by following day most say they have booked it elsewhere.

Some people get so desperate, I have 1 yesterday who booked first thing in morning then cancelled in afternoon because somebody was able to do it 1 day earlier

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#8 ·
Hi RB, thanks for finding the time to monitor TF and contribute, esp. as this must be your absolutely busiest time. Do you get involved in changing condensers....if yes, what's involved with the TDCi?-can it be taken out without removing bumper, for instance.
Hi Oldbod, I sort of knew you're supposed to run the a/c regularly, but didn't know a valid reason for doing it...now I know it's about circulating lube oil around the system, it makes it a valid reason..I don't like to 'have' to do something without knowing a reason to do it...if you know what I mean ????
 
#9 ·
Np,

Yep it is, actually to be more specific past 3 days only have been lol, last week it was just a trickle.

It's only when the heat comes and it hits 28-30 then I get so many calls.

To be honest once book fills up and past few days been solid 7am till 9-10pm it's very hard to return calls or even answer them!

People tend to think bad that they left me a voicemail and I don't reply but problem is, if I get in at 10pm at night I can't start calling people back... It's too late, then following morning in out again lol and vast majority you call back and they say they have sorted it already or don't pick up...so it's a catch 22

So I return a couple and that's about it.

Better to text or email me lol usually in the one telling people to leave me a voicemail and I do usually return them all, just when I get 20 i can't... Physically too many.

But I don't mind coming on here late at night as I'm not doing anything else... Then reply / help people wherever I can... I can be blunt though... And don't like it sometimes when I read about garages or fast fit places who take on Aircon work but don't know what they are doing. That does upset me somewhat..

Had a few jobs past few days, people have had an Aircon system capable of working and didn't have to endure the heat... But because of fast fit places and garages they have gone away believing their Aircon needs a repair.

Had a Renault Megane, it was working before it went in for a service but not getting as cold as they wanted.

Kwik fit left the car powered up while doing a recharge, it triggered an error code for refrigerant pressure... They regassed it and it wouldn't work so they took the gas out again and said it needed a specialist.

I recharged it, cleared the code and away it went.

Had same yesterday with a merc slk, they gassed it, wouldn't work, took the gas out, said it needed a repair.

Just needed error code reset and worked immediately.

One other day, gassed up, lasted a few weeks, leaked out, pressure switch showed signs of leakage for a whole which was why it was empty in first place primarily... 5 minutes to check seeming undertrays were missing anyway would of discovered it.

Another yesterday, garage gassed it, compressor was clicking on and engaging, but they told owner compressor was knackered because it wasn't blowing cold... Glossed over fact that the s-type jags have a common problem with heater control valves causing heater to run on full even if on lowest temp setting.. That is a very common problem even. Poor owner went out and brought a new compressor, and was about to pay £150 for 3 hours labour to fit it.

And even though I do get problems with slow leaks like everyone else, I do identity obvious problems to customers beforehand I know my job and even warrant the gas!

Yet you still get some customers who will book, then cancel because somebody else can do it a day earlier lol that's almost offensive.

Regarding condenser on mk3 mondeo,

Drivers side headlamp removed.

This gives access to the top refrigerant pipe from compressor if I can remember correctly.

Undo that pipe.

Bottom pipe can be undone from underneath, that goes to the pipe on chassis leg with filler if I can remember.

Then it's just a case of 2 bolts if I can remember underneath condenser, either side and condenser drops out underneath.

May have to remove any under shields first.

Haven't had to do 1 on a mk3 yet this year, and some I do the under shields are missing anyway lol, change so many that I have to refamiliarise myself sometimes on how they come out but have a vague idea on most vehicles.

No need to touch bumper though. None of the fords you do usually, fiesta ones can be removed from back, then focus and mondeo all out underneath, same with kuga, s-max, c-max etc.

Fiesta ones are a bit of a pig though because if you are lucky and there's enough room you can remove fan shroud, and then move engine rad out but leave it connected. Then get the condenser out... But if not enough room have to drain coolant and remove the rad.

Peugeots and citroens tend to be same in regards to how condenser and rad is mounted in a frame.

Worst ones are the expensive 4x4s lol

I hate those, they are all designed to remove entire radiator pack... But when you have auto gearbox coolers and everything else it's not my first thought to do.. And they end up taking hours.

Got to have a look at a vw tourareg tomorrow, it was a bit low back in December last year and it triggered error code which shut it down.

I refilled then 2 weeks later did same thing again.

So because I didn't want the nightmare of pulling condenser out, I opted to try a sealer and then recharge it. It's been fine for 6 months, then other day it's shut down again :( it's taunting me I think... So no getting away from condenser now.

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#10 ·
My aircon just clicks on for a second then off for a few seconds and so on.... Aircon is very much out of my ability range and would not attempt to repair or service any parts of it... I do have a thread open I think on this matter or I'm sharing someone else's. Anyway just want to say after reading your posts, what is obvious is that you really know your stuff and secondly, why the hell are you still awake working all those hours? Aha take care mate and thanks for educating me on the systems mines also mk3 tdci ;)
 
#11 · (Edited by Moderator)
My aircon just clicks on for a second then off for a few seconds and so on.... Aircon is very much out of my ability range and would not attempt to repair or service any parts of it... I do have a thread open I think on this matter or I'm sharing someone else's. Anyway just want to say after reading your posts, what is obvious is that you really know your stuff and secondly, why the hell are you still awake working all those hours? Aha take care mate and thanks for educating me on the systems mines also mk3 tdci ;)
Hard to be 100% without gauges attached to watch pressure but sounds like it's low on refrigerant.

Shamefully I don't know the exact pressure off top of my head that the low pressure switch cuts the compressor at. But it's probably around 1 bar seeming most systems run at 2-3 bar on average low pressure side.

So what's likely happening is, with the system low on refrigerant it doesn't take long at all for compressor to pull the pressure right down on the low side.

So if static pressure is 2 bar for example.

Compressor cuts in, suction side will almost instantaneously pull that pressure below 1 bar.

Compressor will cut out.

Pressure will rise back up and return to 2 bar.

Compressor will cut in again.

And cycle continues like that.

I will be heading off shortly, just waiting for my VAG software to reinstall on the laptop, haven't needed it in a while and tomorrow I need it for the touareg lol because I'm going to have to reset the system until I can repair it for them so at least they will have Aircon back again.

They are too complicated now, used to be so simple, pressure switch which switches fans and compressor, and an on off switch inside the car.

Now it's fault codes which shut system down and requires resetting, electronic valves, pressure sensors, permanent drive compressors which never stop rotating, fan controllers, evaporator temperature sensors etc

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#12 ·
Wow thanks for that it makes lots of sense now. Fingers crossed that's my problem.... Would you suggest any particular garage in the Derby area like a main garage or self charging kit you'd recommend? I'd love to be able to bring it to you but like all good things are miles away... Again your knowledge has amazed me.
 
#13 ·
Most likely is, but would need confirming with a set of gauges.

Don't know of any garages in that area.

Would suggest a specialist though, but even then it can be hit or miss, most just use a machine now.

DIY kits don't work properly, need to vacuum the air and moisture out with a vacuum pump and that aside, would require at least 2 bottles of refrigerant from somewhere like halfords and at £40 or so a bottle it's uneconomical and other thing is knowing how much you have actually put into the vehicle by weight

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#14 ·
Here's a bit of humour I came across lol which is actually a good idea.

Alfa Romeo appear on this model of vehicle. To fit cup holders in the engine bay so you can have a cup of tea or coffee and put it down securely while working on your vehicle.

Hood Motor vehicle Light Automotive lighting Automotive tire


It even has a cut out to accommodate the handle of the cup.

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#16 ·
I did thanks then I was out at 7:30am again lol

Here's one from job im doing now, regarding theory of road salt and condensers.

This vehicle is just under 4 years old and comes from Lincolnshire.

Grille Automotive tire Automotive lighting Motor vehicle Automotive design


Bottom has physically detached from condenser, and condenser is starting to go a bit white and powdery.

I would not normally see that on a similar vehicle of same age from here in Essex.

System is also empty. But it still pulls down and appears to be holding a vacuum.

So the alluminium has most likely become porous and it's leaking at a molecular level

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#18 ·
' I have 1 customer with a Ford Focus, it's a 2001 vehicle... And it still blows cold and

has never been regassed in 15 years.'

Just got rid of a Focus 2002 and air/con still worked without ever having a regas

Car has been parked near seafront most of its life, that particular model has

the right air/con equipment whatever was put into it.
 
#19 ·
They aren't common!

What was mileage? Did it so many motorway or dual carriageway miles?

If it did... Then they was lucky the system remained gas tight.

Most mk1 focus I now go out to are all empty. And newer the car the worse they get for leaking and how long they last

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#21 ·
Add the weight reduction and the cost saving from using thinner aluminium plus a tiny increase in performance together and you have a strong case for making condenser thinner. It only has to do two or three years before it becomes someone else s problem. You can't expect the manufacturer to make engines do 200k easy and other bits longer lasting too, where's the margin. Happy customers?
 
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#22 ·
Very true yep lol

Definitely lighter, look at a ford condenser and the cooling fins are now 1.5mm in thickness.

Pattern are 3mm, and 3mm used to be the norm on all cars, also from experience I can tell you when you remove an ancient condenser from something like a Volvo and compare it to new one it's about half the weight.

But the 1.5mm vs 3mm condenser cooling channels is where lots of people go wrong on fords when refilling them.

The sticker on focus 2 and mondeo 4 and fiesta 6? Are for 1.5mm condensers.

However pattern ones are 3mm.

Yet people still recharge as per sticker on the bonnet.. So vehicle ends up undercharged with refrigerant.

Here's an example coming up from my data.

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#23 ·
Font Audio equipment Screenshot Software Astronomical object
Font Astronomical object Audio equipment Screenshot Parallel


It makes sense, a 3mm cooling channel condenser on paper will have I'd imagine almost double the volume of a 1.5mm condenser.

Therefore more refrigerant is required.

Have to say on the mk2 focus and mondeo mk4 it makes a difference with the 3mm condenser and relevant increase in refrigerant. It does blow a bit colder.

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#24 ·
Wouldn't have guessed it was that much of an increase - just goes to show. 140g!. And I suppose if you only charge the original amount, even if it keeps up there's going to be 140g less liquid refrigerant sitting in the airflow through the condenser... be interesting (for someone like me with no proper knowledge) to know how it affects the discharge temp.
 
#25 ·
It does effect it a little bit.

Because the aim is that you should have liquid coming out the of the bottom of the condenser with no gas bubbles. This is one reason why driers are now built into condensers so that you have a storage bottle if you will of liquid refrigerant and is why some of the Japanese cars never gave a figure but instead gave a sight glass and said fill till no bubbles visible then add X amount. But they don't tend to fit them now citing safety reasons, glass exploding in face? Eyes?

Then the expansion valve or the orifice tube regulates the flow of refrigerant into the evaporator, at the point of the valve it's expanding from a liquid into a gaseous liquid and aim is that you should have enough liquid content that some reaches all internal surfaces of evaporator because the liquid evaporates on the internal surfaces of the evaporator and removes heat with it.

That's why when the systems get low, some people say they are experiencing funny symptoms like it's getting cool on 1 side of the car and not the other. It's because by the evaporator is parallel flow, like a condenser usually now, and by the time the gaseous liquid has travelled through half way it's all evaporated. And because of the way the airflow is split inside the heater box the side with refrigerant evaporating is cool and side without is warm.

This is also another reason why orifice tube systems generally get colder because they are quite inefficient and some liquid refrigerant always exits the evaporator so there is often too much entering it at times... This is why the accumulator is fitted after the evaporator to allow any excess refrigerant to evaporated so only gas enters the compressor.

However most systems use the expansion valve now because refrigerant can be metered depending on demand so you only ever get the cooling you need rather than over cooling, coupled with a variable displacement compressor and you get fuel savings due to less load on engine when not required... Also why lots are now electronically controlled.

However back on topic, what then happens is, the quantity of refrigerant on the sticker is calculated for a 1.5mm condenser design.

In simple terms..If you use that figure for a 3mm design what will most likely happen is there won't be enough refrigerant coming out as a liquid..: because instead of X amount always being in a liquid state ... Some of that will be further back in the condenser in a gaseous state... So i would expect some bubbles in the refrigerant .. This then has a knock on effect further down the system so efficiency will be reduced.

But they use a thinner design for a few reasons, less refrigerant so they can claim to be more environmentally responsible.

Less weight so they can make the car lighter which in turn beings fuel economy savings.

Gassing with original sticker amount will still blow cold, just not as cold as it should.

But with the 3mm core they do also blow colder, because greater surface area means greater efficiency, it has a greater surface area to condense the refrigerant into a liquid.

Then the larger diameter channels also mean they are less restrictive so refrigerant flows easier.

Best example I've seen of this was on Renault Megane II, only actually took notice last week because I went to 3 in 1 week and 1 I did a repair on.

But they also have 1.5mm core from new and pattern is 3mm.

First one I went out to I admit it didn't feel icy cold it had a bit of a chill to it... But wasn't great... Owner even was disappointed and asked if I could recheck it. I changed the cabin filter which made a slight difference but still wasn't great... Unless you rev'd the engine a bit.

Then I went out to another one a day later which kwik fit took the gas out of with ignition on and it triggered an error code shutting system down until reset... Gassed that up and it was identical to one I did day before.

Then, on Thursday, I had to do a condenser repair, I replaced condenser and drier on it, there is no quoted increased figure for those so still refilled same amount although probably slightly under filled with the 3mm core for same reason as mentioned above.

When finished, started it up and that was icy cold.

So 3 vehicles, 2 with 1.5mm core, 1 with 3mm core, all 3 same quantity of refrigerant and only 1 which blew really cold.

Only problem I have sometimes on the fords though, is when customers watch me and have seen the sticker and see how much I'm putting in... They start questioning me on why I've overfilled it (I haven't, but they think I have because I've filled for 3mm core and they see 1.5mm fill sticker)

So now if they are watching and start taking an interest in the sticker quantity and watching my scales... I have no choice but to fill as per sticker so their car ends up technically under filled because if anything went wrong they would most likely say I broke their Aircon because I put more refrigerant than the sticker. So it does create problems sometimes having a different fill quantity for pattern condensers.

Haven't had any come backs yet though saying the system has broke as a result though lol so must be doing something right
.

But for anybody reading, focus 2, mondeo 4, fiesta 6/fusion if you have condenser changed to a 3mm design... The fill is not per sticker, it requires a larger fill quantity.

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#26 ·
Hi All, on the hottest day of the year my a/c didn't work in fact, the symptoms are more or less the same as this thread:
http://www.talkford.com/community/topic/291842-ac-starts-and-stops-continuously/?view=getnewpost
with the compressor starting and stopping continually. Also, the twin cooling fans don't run. The condenser has been shedding those aluminium fin things for years...how easy is it to change or should I take it somewhere to get the gas contained-if there's any left in the system. What's the easiest way to test those fans, and should they run as soon as the a/c gets turned on? How easy is it to replace that condenser. Thanks for all ideas. RB2004, don't suppose you cover Leicester by any chance?
It's relatively easy to change providing you have the tools and are a moderately experienced working on cars. There are no 'specialist' tools required, just need socket set, jack, axle stands and a couple of screw drivers. The Mk3 condensers protrude a couple of inches below the radiator picks up all the crud from the road. A new one is about £80, need to get the car degassed prior to starting work as it is illegal to release the refrigerant to atmosphere.
 
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