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Any actual expert views? I've already read a lot of internet wisdom on this topic.
I've read many posts, mostly American, explaining why leak stoppers are bad. However I've also read posts that say the more recent varieties are different and not bad.
I had a garage look at it. They said they looked as best they could and could not find a leak, that suggests to me it's in the evaporator or somewhere and hence requires an expensive time consuming strip down of the interior. And yes, we are going on holiday in a week.
I've got some STP stop leak, it's not clear what it's actually going to do, if anything, or if it will ruin something.
I think that refrigerant evaporates, which makes leaks tricky to find. Sometimes you'll be lucky with a visual check but mostly it's a pro job with either a dye or a refrigerant "sniffer"
There is an STP AC product but it's called Super Seal. I'd go pro first and hope that it's a simple fix
Dunno about STP stuff but our Xtrails air con would go warm after about 3 months. Had it regassed & some fancy sealant put in. That was about 2 years ago & it's still ok.
Except the interior blower failed 2 days before we came down to Dorset, so the air con works but we have nothing to blow it out with!
I now think my favourite garage did a poor job and charged me a lot for it. Ah well. I've found a specialist place that I'm going to ring first thing tomorrow, they offer the fancy stop leak stuff.
I’m going to ring first thing tomorrow, they offer the fancy stop leak stuff.
Just make sure they put the right amount in, ours needed 2 'doses' as it's a bigger than average system apparently.
ive had a lot of dealings with pros and the like. basically your into swapping out bits until it works again.
you can check the clutch, pressure, compressor etc all by yourself. find out of the evaporator has a dryer in t as well or if its separate.
The error code was low pressure, according to the garage (who are great at mechanical stuff but apparently not aircon specialists). It worked fine after they re-gassed it, but not 24hrs later. Which I appreciate is outside the recommended amount of leakage for stop leak type solutions. There's also a smell which I am fairly sure is R134a
There’s also a smell which I am fairly sure is R134a
We also get an odd smell, dunno what R134 is but the air con seems to be working ok, apart from the knackered blower.
I stuck a can of the superseal stuff below in our old fabia this week to see if would sort a slow leak in the AC system. Given the age/value of the car, and the fact the AC hasn't worked for ages, I figured it was worth a gamble at £25 given I needed a can of refrigerant to charge the other car up anyway.
Two days in and all seems well but, unfortunately, you'll have to wait a few weeks until I can actually say it's fixed anything as it was taking a couple of weeks to give up last time I had the system re-gassed. Admittedly that was more than seven years ago, so its quite possible I'll be able to report back sooner if it doesn't work.
I can't use the stop-leak myself, nor can I put more gas in, because for both you need the compressor running. The car has detected the low gas situation and will not run the compressor...
Following this. My Civic air con needs sorting out and garage say it's a leak and needs new condenser, and want to add replacing the radiator at the same time as it shows signs of a leak at some point and cheaper to do that at the same time (but no guarantee is necessary). Would sort it, but it's a 2008 car and cost is half the value of the car really.
I had to top up the gas from empty with the compressor off as it had been empty for years. Seemed quite happy to kick in once I’d done that but as far as I know it doesn’t have any sort of diagnostics to check the levels so nothing to reset once charged.
Edit: I say top up when what I really mean is just put a very small amount in so that the pressure gauge wasn’t reading a big fat zero even with the compressor off.
@molgrips let us know how you get on and for goodness sake don't start ripping the thing to bits a week before your holiday 🙂
This is the Mercedes?
My '68 plate focus had a leak in the evaporator (I think) which meant the dash had to come out.
It's rattled infuriatingly from that day on.
Appreciate the fit and finish on a Merc is probably better than a Focus, but still, a good chance of a clip getting broken and rattling about.
It worked fine after they re-gassed it, but not 24hrs later.
they should have done a leak test on the system first, instead of pumping greenhouse gasses straight into the atmosphere. Please don't use them again.
they should have done a leak test on the system first
They did. Couldn't find a leak, we both just assumed it'd become low after 9 years of use.
I say top up when what I really mean is just put a very small amount in so that the pressure gauge wasn’t reading a big fat zero even with the compressor off.
Considering doing this as a hail Mary, as long as I can be sure that the leak stop I have is not the kind that screws up your system. But I also don't want to pump a whole can of gas straight into the atmosphere either.
And yes, the Merc 🙁
you say that - but the aircon was still working on my 51 plate mk1 Focus (never having had a leak or having to be re-gassed) when I finally got rid of it in 2020!My ’68 plate focus had a leak in the evaporator (I think) which meant the dash had to come out.
It’s rattled infuriatingly from that day on.Appreciate the fit and finish on a Merc is probably better than a Focus
The aircon worked on the Passat after 15 years, Kwik Fit were adamant it didn't need a regas. However when I had them regas it anyway it worked far better.
Just watched some YT vids on people looking for leaks to see what I'm looking for. Went back out and there is now a clear big oily mark at the pipe coming out of the bottom of the condenser, and on the undertray beneath it. That can only be the aircon leak. I may drop the undertray for a better look later - there's a chance it's the junction on the bottom of the condenser rather than the unit itself. No idea what the fittings are or if it's a case of replacing o-rings or something. I don't want to poison myself.
zilog6128
you say that – but the aircon was still working on my 51 plate mk1 Focus (never having had a leak or having to be re-gassed) when I finally got rid of it in 2020!
molgrips
Full MemberThe aircon worked on the Passat after 15 years, Kwik Fit were adamant it didn’t need a regas. However when I had them regas it anyway it worked far better.
Yeah sorry both, I obviously wasn't clear.
I was just intending to say be very cautious about a garage removing the dash, rather than any comment on the reliability of the Focus. With the best will in the world, they're under time pressure to get the job done, so the odd clip getting broken or wire not being clipped in properly could happen easily (as on my car).
molgrips
Full Member
I can’t use the stop-leak myself, nor can I put more gas in, because for both you need the compressor running. The car has detected the low gas situation and will not run the compressor…
I need to do similar as the system is low - the process I've been told to follow is:
-Start car
-AC on, blowers onto max, recirculate button on
-Top up refrigerant until compressor kicks in (assuming it does)
-Add stop leak
-Top up refrigerant again
-Pray you haven't just wasted £100 on greenhouse gases that are now in the atmosphere
Yeah, that's the process as long as the compressor can actually run. On some cars, including mine, if it's low enough it won't let you turn it on. The a/c light in the car just blinks and then stays off. I don't know if adding gas anyway will be enough to override this.
We've just had this issue with a used Aygo 'Blue' we bought in November.
I had it re-gassed properly in April, and the garage found no leaks, pressure tested etc, but the A/C stopped again after a couple of weeks. At least I knew it worked. Bought a kit from ebay - Thompsons air con recharge kit. In the pack was a bottle of conditioner/sealer and a top up bottle of gas 'replacement' and a gauge !
Connected and opened the gauge, and in went the conditioner. Compressor kicked in immediately once the pressure was up. Now, the car's not super fancy on computers etc, but it won't engage the compressor if pressure is too low or high, hence use the gauge ! Bigger cars may need both bottles. I only needed the conditioner to get my system working. Oh, and when fitting the gauge to the low side, pull up the locking collar first before pressing down onto the port - I didn't and lost some of the original gas !
Drove the car a couple of weeks but on 'poking about' in the engine bay I found that one of the sensors on the high pressure pipe was 'bubbling' where it's bolted to the pipe. The sealer/conditioner was bubbling out - too big a 'gap' to seal. Nipped the nuts up and bubbling stopped. Then dropped in the remaining 'gas'.
The car's been perfect since - now July. I've also got a STP Leak stop in 'stock' in case I needed to use it again. This is supposed to seal some small holes.
It's worth a try if there is a minor leak. My 'other car' has had a new a/c radiator and a cracked pipe replaced - that was sudden loss of gas !
They did. Couldn’t find a leak,
a leak test isn't about finding a leak, its about applying pressure to the system to check no air can leak in or out. done properly it would easily pick up a significant enough leak to put the system out of use in <24 hours. This is a legal requirement to avoid CFCs heading into the atmosphere.
leak finding is putting flurescent dye in the system and seeing what its splattered on, to identify where it is coming out of, after the first test has failed. It appears they've jumped straight to the second test having ignored/failed to correctly do the first.
PS this refil gas is compatible with the existing refrigerants, and isn't as environmentally damaging.
PS many air con places won't like to empty and fill your system after you've used this stuff - you may have to play dumb that you know now't about it, but then again, you'd just use the kit again if you needed a top up.
Given the number of folk I saw driving down the motorway with windows down, in relatively new cars, faulty a/c is very common. It's something I can't do without these days !
PS this refil gas is compatible with the existing refrigerants, and isn’t as environmentally damaging.
Which gas .... You can't mix r134 and the more environmentally friendly r1234yf .....
The condensers are designed to work with the relevent gas an firing r1234yf can result in freeze up of condenser in winter.
My old V6 Gold had a leak in an air con pipe behind the engine, apparently they had to take the engine out to replace the pipe - £900 all in! Pipe alone was something insane like £270 for a 3' section. Quite glad I don't have that car anymore....
a leak test isn’t about finding a leak, its about applying pressure to the system to check no air can leak in or out.
They pressurised it with nitrogen and used soapy water on it. There are knowledgeable sounding professionals on YouTube doing it so it's not that far out. But I don't think he looked that hard as the oily mess is quite obvious. Disappointed in them.
I'm going to take the undertray off and take a look at the bottom of the condenser. If it's clearly the o-ring I might take my chances with a fix. According to the parts diagram it should just bolt together.
Only issue is that the driveway is in the full blazing sun!
molgrips
Full MemberI’m going to take the undertray off and take a look at the bottom of the condenser. If it’s clearly the o-ring I might take my chances with a fix. According to the parts diagram it should just bolt together.
Only issue is that the driveway is in the full blazing sun!
just before you need the car for a holiday though? 😬 I'm getting stressed out on your behalf
Not just before, no. 6 days before!
This isn't structural though. The worst that can happen is we have no aircon*, and we've got no aircon now.
* or I poison myself
Refrigerant contains an oil to lubricate the pump. When it leaks out, it can leave slight oily marks which may help detect leaks.
I dunno, does this look like a slight oily mark?
[img] 
[/img]
That's the bottom of the condenser, behind a plastic flap. But the oil mark is clearly visible in the engine bay, which is what led me down there. Bloody garage didn't look very hard did they? Took me 10 mins to uncover that.
Bloody garage didn’t look very hard
We knew that when you described how they looked tbh.
No dye mentioned no black light . No actual looking. Pressure tested and it's leaking go away
I did put pressure on them to fit me into a tight schedule. So they were doing me a favour, or at least they thought they were. But turns out they weren't.
That block is apparently the expansion valve. Not listed in the EPC, available from Autodoc sometime in the next month, not from Eurocarparts.
Assuming I can get the part tomorrow, I have options:
1. Replace part myself and recharge with Halfords gas
2. Go back to the garage and tell them to change it, optionally hand them the part, hope that the shame of failing to find such a massive leak makes them do it for me asap.
3. Keep the appointment for the specialist on Wednesday, bearing in mind it's later in the week, closer to deadline, and assuming they can actually do the work there and then and not just a diagnostic with a 'come back in 3 weeks' date to fix it.
I think I'm going to call specialists tomorrow and tell them what I found, ask them if they can get the part and fix on the appointment.
Just to dip my oar here. If you're replacing the O ring mind and use the proper green nitrile ones designed for use in an air con system. Once the leak is fixed the full system needs vacuumed down to remove any atmospheric moisture or you'll have ongoing problems with the expansion valve/orifice in the evaporator freezing up. If you're convinced it's fixed I'd get it to wherever has an air con machine. It does everything from removing all the remaining gas & oil, vacuuming & then refilling the gas and oil.
Groupon do a voucher for this at ATS Euromaster for less than 40 quid. The machine can also add dye to make tracing future leaks easier with a UV light.
After reading this thread earlier, my aircon decided to play up on the way home, only just on the drivers side. Passenger side was icey cold. Which would have been nice for them if I’d had a passenger.
I’m going to take the undertray off and take a look at the bottom of the condenser.
Given the number of folk I saw driving down the motorway with windows down, in relatively new cars, faulty a/c is very common. It’s something I can’t do without these days !
Probably because a lot of them don't use it enough. If you don't run air con for a while it'll dry the seals in the system out and leak. Needs to be used on a regular basis to lubricate the seals.
Not saying this is the cause of all air con problems, but a surprising amount is as a result of this.
My advice would be to get an AC Pro to fix it. My 2013 Doblo needed a new pipe as one of them had corroded through where the rubber had perished on the steel-clip, allowing the steel clip to rub on the pipe. He replaced the pipe (expensive, from Fiat) and the condenser at the same time. He said the condensor was currently fine, but thebumper was going to come off anyway, so for an extra £40 it was worth doing.
£750 and the aircon works, and I am currently very grateful.
It's the actual condenser, not the valve/connector thing.
They bent over backwards to fit me in, brilliant service from Red Dragon Air Conditioning of Pyle near Bridgend.
Update, you'll love this.
Condenser replaced, re-gassed, and another leak sprang up; this time it's in the evaporator. Which requires 10 hours of dash dismantling. The guy reckoned it was probably because no-one had ever re-gassed it or it hadn't been flushed and re-filled - that can cause any air in the system to react with the gas to make it acidic, so it can then corrode the evaporator.
Now there's no chance of that being fixed before the holiday so I'm forced to give up, but that means I can book it in for when we get back. The warranty covers the evaporator, but I highly doubt that the main dealer will take that on so it'll have to be done at the indy. Hopefully they'll do a good job replacing the broken clips and glues and whatnot, cos I don't want to end up with a rattly dash....
Forecast is fairly cool next week though, at least.
Molegrips I feel for you, for years I would always have problems with my cars just before or during a holiday and it was only me and the wife to worry about. Thankfully the air con never broke, probably as before 2007 I didn't have it. And since then I've not had a single issue apart from a puncture in France.
This year for the first time since 1994 I'm taking a German car on holiday (wish me luck) which was the last time I used one on holiday where a total relay/fuse-board melt down occurred. Thankfully my late wife (then girlfriend) was fluent in French and we found a VW Scirocco in a scrap yard that I could get enough bits out of to effect a repair!
Think the scrap yard owner was eyeing up Carolyn for a wife material as he was very impressed about her mechanical/electrical knowledge in French. She grew up around cars, lorries & coaches and her father taught her well
Thankfully my late wife (then girlfriend) was fluent in French and we found a VW Scirocco in a scrap yard that I could get enough bits out of to effect a repair!
That's pretty hardcore!
At least this problem isn't my fault. Nothing to do with me guv I didn't touch it.
Carolyn took it all in her stride as her father was renowned for getting cars MOT'd the day before a holiday or rebuilding the diff/engine/suspension etc.
Don't forget from 1982 till 1997 none of my cars cost more than £900 some £10 so I was used to fairly major fixes.
I think one of the things that keeps aircon systems working is just leaving them on all the time. I've got fed up with people who moan "they are bloody rubbish" then when I ask them how often they use it "Oh not often" that IMO is why they don't work for you then!
I set a comfy temp in my case 18deg C and leave the car to sort it out which mostly leaves the aircon on as you also get warm dry air in the winter so the car doesn’t fog up, another of my pet peeves is people with cars fogged up and dirty windscreens. Just use the bloody thing properly!!!
Some sympathy from me too as my car has had AC issues being investigated by 2 different certified repair places since April and after significant time and money invested it is still not working. Both places actually did not take full price for time spent on investigation which was nice gesture.
They are now quite sure that fairly expensive Front Elektronic Module needs replacement but they are on back order from factory, arrival time in September maybe. Luckily we have other car to use during the hottest days.
Took it into Mercedes, and they said there's no leak. They have a fancy machine that draws a vacuum in the system, and if it detects any leak it won't fill it, but it found nothing. The previous people reckoned it was losing pressure in a few hours so that would have to be a decent sized leak. I'll see if it's still working tomorrow.
Weird though, not sure how come the specialists found a leak. They showed me the pressure gauge having dropped, they showed me the detector picking up gas in the cabin. And they said they wouldn't do the evaporator replacement anyway, so it's not like they were trying to rip me off. Odd.
It worked really well this afternoon at any rate, which was lovely. However this does mean we drove around all holiday without aircon when we didn't have to! My wife even got a bit poorly on the way home because of the heat.
I was thinking about this thread on the way into work this morning. Been a while since I used the can of stop leak stuff and gave it a top up but it’s still blowing out air as cold as the day I did it. Without wanting to jinx something, I think it might have actually worked.
They have a fancy machine that draws a vacuum in the system, and if it detects any leak it won’t fill it, but it found nothing.
I have a similar machine. Vehicle can pass the vacuum stage, but will still leak because the vacuum has pulled a seal (for example) back into place and effectively sealed the system. The only proper check is with OFN or a 'sniffer'.
Small leaks can be bloody hard to find. Most are (in my experience) caused by damage to the condenser from stone chips/corrosion.
If you suspect the evaporator, then seal up the condensate drain and run the vehicle for couple of days. Release the seal and if there is any dye (assuming there is some in the system) visible you've more than likely a leaking condenser. Extremely rare and never worth fixing - unless you DIY. Sell the car if you really want AC.
They said they'd sniffed it and not found anything. I can't figure out what sequence of events would lead to the specialists finding a problem and Mercedes not. But we'll see what happens down the line. The original leak took about 36 hours to empty, but that was the condenser, it was obviously bad and that's been replaced.
There is dye in it. The drain tubes come out on top of the transmission so I can't imagine they are easy to get to, but I might be able to get a UV torch on it and see something.
EDIT hmm detectors are only £20 on Amazon.
@tjmoore
[I]Following this. My Civic air con needs sorting out and garage say it’s a leak and needs new condenser,[/I]
We had an 09 civic, symptoms were that the air con would work briefly and then turn off after a few minutes of driving, so I was pretty sure it was still pressurised. Dealer solution was to replace the compressor (and empty/ refill the system...£££)
I got a recharge from Kwikfit followed by their money back guarantee when it didn't fix it (no leaks found)
After a bit of Googling, I spent a few quid on some shims and took the clutch off the compressor (don't need to empty the refrigerant). It already had the thinnest shim in there so refitted it with no shims.
Result, perfect ice cold air con 🙂
If it's a leaking condenser, it should be very visible. The refrigerant evaporates but it contains oil which gets left behind. When I took the cover off mine underneath it was a hell of a mess - very obviously had been leaking for ages.
The fault-finding process will be driven by the warranty company rather than the local MB dealer and their workshop. It might take several small steps spread over days
Is this your troublesome Mercedes @molgrips?
~20 years ago I had a LWB A-class. Great little car. Aircon became feebler and feebler. MB happily explored it a few times for £££. Typically no fault found and they would re-gas. Only for it to fade away within the week. Problem eventually turned out to be a bent and cracked joint on the ‘radiator’ caused by inept fitting in an earlier inspection.
Good luck.