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E51 E51 Aircon Pipe Corrosion (Rear)

Karl

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This is not necessarily a common problem, but it happens more than it should.

The problem hear is that the Aluminium Aircon Pipes that run to the rear evaporator corrode over time. This might not seem like such a big deal, but when you take into account that replacement pipes are £1000 PLUS, then you have cost of labour to fit them etc... even if the problem is not a common one, prevention is better than cure.

This also adds to the "underseal" thread, also in this section.

On the E51 isa box underneath the vehicle, at the rear on the passenger side. Inside this box you can see the air con pipes. When you get the car undersealed, ENSURE that whoever is doing the work opens this box and coats the pipes thoroughly with underseal. Also, ensure that the inside and outside of this box are thoroughly coated as well.

The box provides the outer protection for the pipes, so looking after that is one part of the problem. But also coating the pipes will act as a secondary level of security to this issue.

it is not the be all and end all of everything if you lose the air con, but we all know how nice it is on a hot day to whack it on and drive in comfort, after all, why pay for a luxury car that you have to drive sweaty and clammy.

For anyone who has had this issue already, or for any E51 owners that find their aircon does not work. Check this area first. If it's broken, there are two options:

1 - blank off the rear air con. This means you'll still be able to use the aircon up front, but you won't get any cold air through the rear vents. If the system is gassed correctly though, the fronts should be enough to help cool the WHOLE interior down, albeit it will take a little longer.

2 - replace the pipe, which as mentioned above, can cost well over £1000 to repair.

Please see below link to see pictures of the affected area, the pipe that needs replacing, and screenshots of purchase price for replacement parts.

https://flickr.com/photos/9778891@N04/sets/72157659861402231



EDIT: Thanks @Phil for correcting the side the box is on :D. And thanks @MrRob_in for the images linked, this will be extremely helpful to future members :)
 
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I'd appreciate if someone could provide pictures of the box, both for location purposes and so people know what we're talking about.

Also if they could provide a picture both outside and inside showing the pipes, it would be greatly appreciated.
 
the box is on the rear passenger side @Karl . It has a hinged inspection flap on it which can be accessed without jacking the vehicle up.

I posted a pic on the forum somewhere so I'll have a hunt for it later unless somebody beats me to it - got to get me bets on for Ascot first ;)
 
How is the Aircon flap fitted is it on a hinge? On my silver Elgrand its in lovely condition, but on the white Elgrand its pretty rusty so I am a bit dubious about unrusting the flap if I cannot close it afterwards! :eek:
 
How is the Aircon flap fitted is it on a hinge? On my silver Elgrand its in lovely condition, but on the white Elgrand its pretty rusty so I am a bit dubious about unrusting the flap if I cannot close it afterwards! :eek:

Hinge at front and two clasps at rear that iirc are best cable tied when they corrode and fail to lock.
 
How is the Aircon flap fitted is it on a hinge? On my silver Elgrand its in lovely condition, but on the white Elgrand its pretty rusty so I am a bit dubious about unrusting the flap if I cannot close it afterwards! :eek:
Spray it all up first Richard with some WD40 then open it, clean it all both sides and inside around the pipe union. Would do no harm tom spray wax oil all over inside and the flap too matey for longevity protection.:p
 
Just started getting the dreaded green drip from the box not been brave enough to open it yet
 
geez thats it i be checking mine tomorrow.
and Fish oil the fark out of it !
 
Plumbing is plumbing you'd be crazy to spend a 1000 quid on it, I've replaced the front to back pipework on a kia sedona and a Citroen C8 with home made pipework. Fiddly routing and took time and planning but very doable.
 
I had mine at an Air Con place today as it had stopped working. I had heard a telltale hiss from the rear passenger wheel section.

On inspection today the double walled two pipes in one is leaking a little bit before it enters the rear box and splits out. See these threads:
https://forum.elgrandoc.uk/threads/aircon-leak.5563/
https://forum.elgrandoc.uk/threads/e51-rear-aircon-leak.3203/
https://forum.elgrandoc.uk/threads/ac-not-working.7750/
Very helpful cross section photo of the pipe I'm describing as "two pipes in one" in the third thread.

My pipes do not look corroded and the part leaking is actually under some insulation so was protected from the worse of weather, I'm not confident that undersealing them would have made any difference but it certainly wouldn't do any harm. I think its more the age of the pipes and likely that slight impurity in its manufacture has failed, I've seen similar impurity pinholes in household copper water pipes.

Not knowing anything about air con I asked if this was a common problem on other cars and the answer was yes, this twin pipe in one arrangement is common place on all modern cars and replacement with a pre-manufactured pipe is usually the answer but obviously more costly for us if that has to come fro Japan.

Owing to its construction he could not splice in another piece but his suggestion is to run two separate pipes from front to rear. Although a more involved job he said it would be possible.

I also asked whether regular re-gassing every few years or so would be beneficial, he didn't try and drum up regular revisits by immediately saying yes, he said it probably wouldn't be a bad idea but that the pipes really only last a certain length of time and they are getting to that age.

Unfortunately I need my air con working sooner rather than later owing to pet transportation and there isn't time to run the separate pipes. However I'm going back next week when he will blank off the rear pipes at the front with fittings so if I find air con only in the front cab inadequate I can go back and have the pipes run front to back at a later date to return to a full system. Will see how it behaves afterwards and make my decision on this as it will likely be expensive.
 
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I had mine at an Air Con place today as it had stopped working. I had heard a telltale hiss from the rear passenger wheel section.

On inspection today the double walled two pipes in one is leaking a little bit before it enters the rear box and splits out. See these threads:
https://forum.elgrandoc.uk/threads/aircon-leak.5563/
https://forum.elgrandoc.uk/threads/e51-rear-aircon-leak.3203/
https://forum.elgrandoc.uk/threads/ac-not-working.7750/
Very helpful cross section photo of the pipe I'm describing as "two pipes in one" in the third thread.

My pipes do not look corroded and the part leaking is actually under some insulation so was protected from the worse of weather, I'm not confident that undersealing them would have made any difference but it certainly would do any harm. I think its more the age of the pipes and likely that slight impurity in its manufacture has failed, I've seen similar impurity pinholes in household copper water pipes.

Not knowing anything about air con I asked if this was a common problem on other cars and the answer was yes, this twin pipe in one arrangement is common place on all modern cars and replacement with a pre-manufactured pipe is usually the answer but obviously more costly for us if that has to come fro Japan.

Owing to its construction he could not splice in another piece but his suggestion is to run two separate pipes from front to rear. Although a more involved job he said it would be possible.

I also asked whether regular re-gassing every few years or so would be beneficial, he didn't try and drum up regular revisits by immediately saying yes, he said it probably wouldn't be a bad idea but that the pipes really only last a certain length of time and they are getting to that age.

Unfortunately I need my air con working sooner rather than later owing to pet transportation and there isn't time to run the separate pipes. However I'm going back next week when he will blank off the rear pipes at the front with fittings so if I find air con only in the front cab inadequate I can go back and have the pipes run front to back at a later date to return to a full system. Will see how it behaves afterwards and make my decision on this as it will likely be expensive.

Great post - please let us know how you get on
 
I found that my air conditioning over the last few weeks has not been cooling down as it used to even though I had it regassed last year. Thanks to the information that people give on this forum I looked at the pipe at the back and there was a small amount of green fluid around the pipe just before it went into the box. I opened the lid of the box and it was in perfectly clean order, a bonus. There was some corrosion on the aluminium aircon pipe just under the rubber protection pipe so I split this and pulled it out of the way, removed the box, just 2 screws. I cleaned up the aluminium pipe with some white spirit and carefully went over the pipe with some sandpaper to roughen it and then cleaned all again with white spirit. I had some 2 pack good quality epoxy resin that I got from a modelling shop so I cut some kevlar from an old pair of motorcycle jeans (well they were a good pair but my belly’s got to big) (fibreglass tape could be used) cut this into 1” x 6” strips (25 x 150mm for you young ens) mixed up the epoxy resin then soaked the strips in it before wrapping it around the pipe, make sure to clean the pipe again with white spirit before wrapping it around. I mixed the epoxy up to give it a curing time of about 30mintes. There was still a small amount of aircon fluid leaking out from the kevlar bandage but by the time I gave it another clean and and wrapped some more epoxy soaked kevlar over the area it had stopped. The second wrapping I mixed the epoxy to go off in about 5minutes. I wrapped further up the pipe than was necessary and almost on to the connection to give it some protection. Finally I cleaned up the box gave it a coat of paint put everything back and put a good coating of underseal over the lot. Got the aircon regased and fingers crossed, all’s been well. Fortunately I got to the pipe in time as the corrosion had not been too bad, mainly pin holes so this idea might not work for all cases. If the corrosion has got worse it might be an idea to have any remaining gas evacuated then put some very thin aluminium over the area then wrap it similar to what I have done. Only time will tell if this has worked for me, I had nothing to loose apart from a bit of time plus some extra pain getting under the vehicle.

5th November 2018. Just thought I would do an update, a bit late from when I first did the write up, sorry about that. Well my idea didn’t last more than a month so it’s back to the drawing board.

Gramps
 
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@Gramps, very interesting, please update the thread say at the end of the summer (if you can remember) to let us know if it still works?

I'd wondered about something along those lines but knowing the high pressure was put off by the idea as needed it working quite quickly so didn't really have time to have a go, chance the re-gas and hen possibly have to have it looked at again.

Maybe even chemical metal under the sheet aluminium as you suggest as a base coat over bigger corrosion problems.
 
I had mine at an Air Con place today as it had stopped working. I had heard a telltale hiss from the rear passenger wheel section.

On inspection today the double walled two pipes in one is leaking a little bit before it enters the rear box and splits out. See these threads:
https://forum.elgrandoc.uk/threads/aircon-leak.5563/
https://forum.elgrandoc.uk/threads/e51-rear-aircon-leak.3203/
https://forum.elgrandoc.uk/threads/ac-not-working.7750/
Very helpful cross section photo of the pipe I'm describing as "two pipes in one" in the third thread.

My pipes do not look corroded and the part leaking is actually under some insulation so was protected from the worse of weather, I'm not confident that undersealing them would have made any difference but it certainly wouldn't do any harm. I think its more the age of the pipes and likely that slight impurity in its manufacture has failed, I've seen similar impurity pinholes in household copper water pipes.

Not knowing anything about air con I asked if this was a common problem on other cars and the answer was yes, this twin pipe in one arrangement is common place on all modern cars and replacement with a pre-manufactured pipe is usually the answer but obviously more costly for us if that has to come fro Japan.

Owing to its construction he could not splice in another piece but his suggestion is to run two separate pipes from front to rear. Although a more involved job he said it would be possible.

I also asked whether regular re-gassing every few years or so would be beneficial, he didn't try and drum up regular revisits by immediately saying yes, he said it probably wouldn't be a bad idea but that the pipes really only last a certain length of time and they are getting to that age.

Unfortunately I need my air con working sooner rather than later owing to pet transportation and there isn't time to run the separate pipes. However I'm going back next week when he will blank off the rear pipes at the front with fittings so if I find air con only in the front cab inadequate I can go back and have the pipes run front to back at a later date to return to a full system. Will see how it behaves afterwards and make my decision on this as it will likely be expensive.
One of the " MAIN " reasons to have your aircon re-gassed every 2-3 years is because the refrigerant fluid has a lubricating oil in it which helps keeps the main aircon compressor working fully all the time thus it does not dry out the seals and seize up.
 
I found that my air conditioning over the last few weeks has not been cooling down as it used to even though I had it regassed last year. Thanks to the information that people give on this forum I looked at the pipe at the back and there was a small amount of green fluid around the pipe just before it went into the box. I opened the lid of the box and it was in perfectly clean order, a bonus. There was some corrosion on the aluminium aircon pipe just under the rubber protection pipe so I split this and pulled it out of the way, removed the box, just 2 screws. I cleaned up the aluminium pipe with some white spirit and carefully went over the pipe with some sandpaper to roughen it and then cleaned all again with white spirit. I had some 2 pack good quality epoxy resin that I got from a modelling shop so I cut some kevlar from an old pair of motorcycle jeans (well they were a good pair but my belly’s got to big) (fibreglass tape could be used) cut this into 1” x 6” strips (25 x 150mm for you young ens) mixed up the epoxy resin then soaked the strips in it before wrapping it around the pipe, make sure to clean the pipe again with white spirit before wrapping it around. I mixed the epoxy up to give it a curing time of about 30mintes. There was still a small amount of aircon fluid leaking out from the kevlar bandage but by the time I gave it another clean and and wrapped some more epoxy soaked kevlar over the area it had stopped. The second wrapping I mixed the epoxy to go off in about 5minutes. I wrapped further up the pipe than was necessary and almost on to the connection to give it some protection. Finally I cleaned up the box gave it a coat of paint put everything back and put a good coating of underseal over the lot. Got the aircon regased and fingers crossed, all’s been well. Fortunately I got to the pipe in time as the corrosion had not been too bad, mainly pin holes so this idea might not work for all cases. If the corrosion has got worse it might be an idea to have any remaining gas evacuated then put some very thin aluminium over the area then wrap it similar to what I have done. Only time will tell if this has worked for me, I had nothing to loose apart from a bit of time plus some extra pain getting under the vehicle.
Hi I just had my air con checked today he said it's leaking from the rear e51 ,mines three sections I will be trying to remove the pipe section Saturday see what I find .just spent £600 on new tyres drive shaft gators and not car looks fantastic but no air con boo boo.
 
I have just been searching for the rear section of the 3 part pipe used as a replacement pipe so the suspension dosnt need removing to fit the single piece pipe its 92460-WL062 which Nissan states as discontinued.
 
I have just been searching for the rear section of the 3 part pipe used as a replacement pipe so the suspension dosnt need removing to fit the single piece pipe its 92460-WL062 which Nissan states as discontinued.
Are you gonna start stocking this Brian so you can fix folks Elgrands that have the leak issue???
 
There must be someone out there who could manufacture a replacement pipe in 3 sections who could make some decent money on these surely.
 
I have just been searching for the rear section of the 3 part pipe used as a replacement pipe so the suspension dosnt need removing to fit the single piece pipe its 92460-WL062 which Nissan states as discontinued.
I got quote for part £192 from Japan from the garage I had the work done they suggest separating rear first as they are difficult to split ,will see Saturday.
 
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