Aircon pipe leak repair

Car was in for a service last week. Aircon leak picked up from the pipe that runs over the driverside of the engine down to the sill - small pin prick in the pipe (see photo). I've read it's an engine drop to get this pipe out and the pipe is also a couple hundred £. Can anyone confirm any of this or if there's another easier method? I was contemplating vaccing out the system and then getting under the car and welding over the hole. Does anyone know if this is possible or not? Other option is cut the pipe where the hole is and re-join with a Yorkshire fitting, but seeing as it's on the bend may prove a bit tricky. I could also cut that section out, make a new pipe section and fit one on either side, or just make myself a new end section and fit a joint further up. Any thought? Leak: Mechanic taped over it so I can easily spot where it is:

I think you may need to drop or lower the engine to replace, it's the hard line that runs up to the right side of the engine bay and onto the flex pipe, looks very tight in there. I'm sure dM will be on later with some actually facts rather than guess work? When one of my front to rear pipes went I bought a used one, it's been fitted to the car for nearly a decade without leaking yet so that route may save quite a bit of cash?

Bodge job :lol: https://www.everbuild.co.uk/product/silweld/

I'm not fussed about spending a couple hundred on the pipe, it's the engine drop to do it that's putting me off. Welding I can do without having to even disconnect anything, never mind removing stuff. Long pipe that runs the length of the car was brand new a couple of years ago so that joint should easily come apart. If welding is a no-goer, I may just cut that section out and make a new piece at work and connect it up further along with a Yorkshire fitting.

I just put a blob of JB Weld over a small crack in my pipe where it was crushed by the front jack point. It's holding up OK a few years later.

Hey I'm liking this - good find!! :thumb:

Brazing would be my bodge of choice, we used to do this to aluminium radiators that had sprung a leak.

Yeah I was also wondering if brazing / soldering would also do the job. I'll have a word with my welder and see what he thinks.

r12 and to a degree r134 when heated too much breaks down into some nasty stuff .. Phosgene i believe . Obviously you will have taken the gas out before welding but i have to wonder if pag oil can absorb some of this and when heated cause a similar reaction .. In short i can only say that having seen a mechanic use heat trying to get the rear connections undone .. He ended up breaking the pipe but the pag oil that came out was boiling and the gas was pretty acrid stuff .. made our eyes sting . That was back in my OPC days ... i've never used heat on these pipes and probably won't ever after that incident . I can't say if its bad or not .. i can only go through past experiences .. obviously a respirator if doing this is a good idea . Strange as it may seem but porous holes are a by product or a poorly functioning a/c dryer .. water and the compounds in the oil create an acid which eats through the pipes .. worth changing it if it's old and always if the system has been open to the air for any length of time . yes to change this pipe you need the engine dropped .. if you can get away with a mechanical fix then i feel that's the best option . Things like JB weld might work in the short term but you have to remember there are high pressures in the system .. 25 bar on the high pressure side . just my 2 pennys worth anyways .

Hydroflouric acid! now thats if the PAG oil changes state, as Demort said. Im thinking that its not impossible to weld this pipe, however Aluminium welding needs cleanliness. you may get lucky and the weld works well and seals it, its likely with the leak and the PAG oil in the system already you may contaminate the weld. I think if you can do the fit with the Yorkshire fitting, thats worth a go as you are likely to need to swap the pipe anyway?? I don't recommend the air con leak sealant, its like chewing gum and get around everything causing problems let us know how you get on

:agree: The expert here is above .. can i just ask .. am i correct in that this gas R134 does break down into Phosgene like R12 with heat ? There is no one i can ask and i would love to know . I couldn't remember the name of the acid so thanks for that .. down side of reading so much over the years and getting older .. i don't remember it all .. sigh

I would try the tape or the JB Weld before taking the engine out!

:agree: If JB or similar works, all good. If it doesn't, you are only about £50 less well off - price of a tube of stuff and a vacuum and pressure check at Kwik-fit

Thanks guys - some interesting info and advice. I'll speak to both my aircon man and welder and see what we can come up with.

...let us know how you get on Alex...