• Welcome to the ElgrandOC forum.

    You will find that the majority of the forum is locked, but do not worry. You can unlock more content by registering to the forum completely free. Sign up is automatic, does not require email confirmation and is instant. Feel free to browse through the sections to see what topics have been covered before you register.
    You can register for an account by CLICKING HERE

    Once you have registered, you will unlock more of the forum content. You will not unlock all of the content until you have reached 10 posts. This is to give you an opportunity to chat to existing members and help to integrate you into the forum community.
    We are a friendly and helpful community and there is a wealth of infomation contained within the forum. Please feel free to register, introduce yourself and get to know your fellow members.

    Feel free to look at the Frequently Asked Questions section, the Meets/Events section and the Competition Section without having to register.
    We look forward to getting to know you and help you with any questions or problemd you have with your Elgrand.

E51 E51 Aircon Pipe Corrosion (Rear)

Cheers Simon - very insightful as usual. I did go through all the post (quickly but did) and picked up the point about the rear heater unit being in this area as well - that's why was thinking that might not be a straightforward - yes it's the AC pipe.
And yes by the box - I meant the external box with the flap (that I have on the picture - probably not easy to identify from this pic). Ok - will need to get somebody to look at it and confirm where the leak comes from.

And completely agree with you - I would rather have the back heater and Ac working (I assume the heater works if the back AC gets blanked - as you mentioned the AC pipes and heart pipes are different as i assume is on all cars?! - otherwise the car goes before the winter) - if there was somebody close by willing to do the work - I will happily pay for it - will even travel (although this becomes a challenge if it is too far but willing to do it to get it sorted properly). With young family (and baby on the way) and this currently being the only car this is not ideal by a long stretch but a reality with an old car and being a grey import. I take it if the rear AC gets blanked - it still can be sorted properly afterwards (with pipes replaced)? Although most likely the car ill be replaced before this happens.

If you are willing to sort few things out - happy to come and visit you and make it worthwhile for both of us (need a calibration of the LPG system as well - so can wrap it all up) 😊.

Would like to help but I don't expect to get time to work on customer's AC systems anytime soon mate.

I have fixed the AC systems on both of my E51 Elgrands, both had the usual hole at the rear end of the front to rear AC pipe, I fixed them both by changing the front to rear AC pipe... Which involves lowering the back axle. But lowering the back axle isn't too difficult for anyone handy with the spanners, can be done on a driveway with a couple of jacks. Elgrand scrappers like Stevemen sell second hand front to rear AC pipes. Or as you know BMR sells the blanking plate (but blanking plate means the rear AC won't work). I don't have an AC machine here, I do have one of those Halfords DIY AC regas setups but would be better (and cheaper) to have the AC system re-gassed at (say) a Kwik-Fit. But of course Kwik Fit and similar setups won't get involved in fixing the AC.

Could probably see you a lot sooner for LPG system checks/repairs/putting right. I assume it's not one of my LPG conversions?
 
I went for a re-gas the other day as mine has only just stopped working, its gone in the usual place so got the blanking plug from Brian and its in tomorrow and hopefully have some aircon again. I should have coated it but kept putting it on the backburner. I had awesome service from Brian, the part was here next day👍
 
Am I correct in thinking that the pipe will only leak when the rear air con is in use? I tend to only use the front air con so would not using the rears effectively stop the problem getting worse and avoid the need for blanking plates and re-gassing?

No, as others have implied there are not really 2 separate AC systems, there's only 1 AC system that has 1 condenser (front AC radiator) and 2 evaporators (1 in the front heater box and 1 in the rear heater box). Even if you turn off the rear AC the rear evaporator is still part of the system and still gets cold, just that with rear heater turned off the fan is turned off and no (or very little) air goes through the rear evaporator. One system, all the pipes are connected.

Even if AC is turned off front and rear, if there's a leak anywhere on the system it will still leak.... A simple analogy would be if there's a hole in your car tyre it will still go flat even if you're not driving it.

There's another potential problem when you've had an AC system leak.. In the AC system there's the refrigerant gas and there's the oil that lubricates the AC pump. When you go for a regas the machines measure how much oil was sucked out and aim to put the same amount of oil back in.... But if you've had a leak you can't be sure how much oil came out with the gas, while the machine will only put back in the same amount of oil that it sucked out. So following a leak / repair / regas you could end up with less oil in the system than should be in there, but if you explain that you've had a leak and lost some oil and ask them to put a bit more oil in to compensate nobody can say for sure how much oil extra oil should be added and too much oil could be as bad as not quite enough.
 
Last edited:
No, as others have implied there are not really 2 separate AC systems, there's only 1 AC system that has 1 condenser (front AC radiator) and 2 evaporators (1 in the front heater box and 1 in the rear heater box). Even if you turn off the rear AC the rear evaporator is still part of the system and still gets cold, just that with rear heater turned off the fan is turned off and no (or very little) air goes through the rear evaporator. One system, all the pipes are connected.

Even if AC is turned off front and rear, if there's a leak anywhere on the system it will still leak.... A simple analogy would be if there's a hole in your car tyre it will still go flat even if you're not driving it.

There's another potential problem when you've had an AC system leak.. In the AC system there's the refrigerant gas and there's the oil that lubricates the AC pump. When you go for a regas the machines measure how much oil was sucked out and aim to put the same amount of oil back in.... But if you've had a leak you can't be sure how much oil came out with the gas, while the machine will only put back in the same amount of oil that it sucked out. So following a leak / repair / regas you could end up with less oil in the system than should be in there, but if you explain that you've had a leak and lost some oil and ask them to put a bit more oil in to compensate nobody can say for sure how much oil extra oil should be added and too much oil could be as bad as not quite enough.
I was under the impression that the Aircon pipe in question can now be bought in two sections rather than the original long one piece section for easier fitment?
 
I was under the impression that the Aircon pipe in question can now be bought in two sections rather than the original long one piece section for easier fitment?
I don't know about 'now' but for sure they have been available... I bought a 2 section secondhand pipe from Stevemen (Tojo Motors) for my first (white) E51. But to buy one new and get it over from Japan would have cost over £1000, if available, and even second-hand they fetch a premium over standard single section AC pipes again if/when available. If you can get hold of a 2 part pipe (or 3 part as mine was) then fitting doesn't involve having to lower the rear axle. But you might pay £100 more for a second hand 2/3 part pipe above the price of a second hand single section pipe, if you can get one. Pay £100 extra to avoid lowering the rear axle...
 
I don't know about 'now' but for sure they have been available... I bought a 2 section secondhand pipe from Stevemen (Tojo Motors) for my first (white) E51. But to buy one new and get it over from Japan would have cost over £1000, if available, and even second-hand they fetch a premium over standard single section AC pipes again if/when available. If you can get hold of a 2 part pipe (or 3 part as mine was) then fitting doesn't involve having to lower the rear axle. But you might pay £100 more for a second hand 2/3 part pipe above the price of a second hand single section pipe, if you can get one. Pay £100 extra to avoid lowering the rear axle...
I see your point lol, good job i repaired mine with arraldite 5 years ago after being without it for 6 or 7 years I got fed up and decided to deal with it on the cheap as I didn't have much cash back then.
Needs a regas now as it bearly worked when it was very hot, but now it's cooler blows quite cold
 
after reading the thread with an sense of impeding doom, got underneath mine to be pleasantly surprised. Pipe and connections look to be in decent nick. However prevention seems to be the order of the day and will be ordering some form of gloop to keep them that way.
 
after reading the thread with an sense of impeding doom, got underneath mine to be pleasantly surprised. Pipe and connections look to be in decent nick. However prevention seems to be the order of the day and will be ordering some form of gloop to keep them that way.
Anybody tried Duralac Green Anti Corrosive Compound for Stainless and Aluminium seems to tick the boxed. Seem people use Waxoyl and marine grease but this seems to be particularly designed to help with electrolytic corrosion?
 
I use ACF-50 and Owatrol.
 
after reading the thread with an sense of impeding doom, got underneath mine to be pleasantly surprised. Pipe and connections look to be in decent nick. However prevention seems to be the order of the day and will be ordering some form of gloop to keep them that way.
Mine rotted from the inside out when I cut the pipe open you could see it
 
Mine rotted from the inside out when I cut the pipe open you could see it
Thanks Andy, nought to be done for the inside, all I can do is protect the outside
 
Mine rotted from the inside out when I cut the pipe open you could see it
mine looked clean too apart from the inspection flap but soon the green drips started .
 
its not all bad ,I just cleaned it and put some metal filler around it got me through the summer ,done it again the next year.
 
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.
I agree. Photos would be very handy.
 
I have the problem outlined. Is it ok to run the rear aircon until I get the blanking plate, to provide some coolish air for my dog?
 
I have the problem outlined. Is it ok to run the rear aircon until I get the blanking plate, to provide some coolish air for my dog?
The aircon won't cool air without gas in it. It's likely running without gas will destroy the pump and/or heat exchanger so the whole system would need replacing.
 
This is what I've done to mine.
I used Loctite extra thick to tape round which is water proof and very sticky.
Got an inner tube and put metal araldite on it, wrapped it round on top of the pipe and finished off with jubilee clips as you can see.


IMG_20230527_153005.jpg
IMG_20230527_142244.jpg
IMG_20230527_150658.jpg
IMG_20230527_144409.jpg
 
The aircon won't cool air without gas in it. It's likely running without gas will destroy the pump and/or heat exchanger so the whole system would need replacing.
Thanks. Is it possible to use the rear vents with the aircon turned off?
 
Back
Top