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E51 E51 Aircon Pipe Corrosion (Rear)

roryj said:
How long ago did you order yours?
Click to expand...
With these, it's not how long ago did you order it. Brian has them specially made by an engineering company so many at a time, he fills the orders on first come first served, but then he'll have to wait for the next batch to be delivered from the engineers. Also batch sizes depend on demand etc. He will send it, along with instructions. don't worry
 
ordered mine from @BMR in May. Maybe I should have just ordered online rather than texting him which is his preferred method? Brian says I'm on the list still.

Hope I get it before my trip to the Highlands or it's going to be one uncomfortable long drive :worried:
 
I think I’m going to go down the blanking plate route as I’ve just got the leak and the cost of new pipes is not an option at the minute.

It would be great if anybody who has done this could tell me how much of a difference it makes in day to day use? Are your rear seat passengers still comfy? Does the whole car cool ok in hot weather? Does the back fog up?

it’s rare that anyone sits in the very rear but we often have 4 people in the car so I want it to be ok for them.
 
Hi Matt,
We had the pipe removed and blanked off last October. By then we'd missed the really hot weather, so can't comment on how effective it has been in scorching conditions, but there certainly hasn't been any misting up of the back or rear side (or any) windows.
We rarely carry passengers but when we have stopped and popped into the back for a cuppa (we run it as a campervan) we haven't noticed any difference in comfort between front and back.
Anyway, the peace of mind of knowing that you aren't dropping the green-stuff on the drive and that you do have temperature control again is sooooo worth it.
 
Hi.
Bought our van in 2017, Aircon worked first year but then the drips appeared on the drive and cost of repair made me put the whole thing on the back burner. In summer last year I took a gamble in buying the blanking plate from BMR and getting my local garage to fit and regas. Bit was I think, £40 and the garage charged £125. To my delight the 'op' was successful which slightly surprised me as the Aircon system had been unused and empty for a couple of years, I was expecting dry or perished seals. It throws nice cold air through the face level grills so all good. Not sure fully what it's like in back but it must have some effect. Result is a happy bunny and saving of a great lot of cash. And, many thanks to BMR.
 
roryj said:
Hi Matt,
We had the pipe removed and blanked off last October. By then we'd missed the really hot weather, so can't comment on how effective it has been in scorching conditions, but there certainly hasn't been any misting up of the back or rear side (or any) windows.
We rarely carry passengers but when we have stopped and popped into the back for a cuppa (we run it as a campervan) we haven't noticed any difference in comfort between front and back.
Anyway, the peace of mind of knowing that you aren't dropping the green-stuff on the drive and that you do have temperature control again is sooooo worth it.
Click to expand...
Thanks for the feedback, ordered one today so it’s good to hear you are happy with the fix.
 
Ravers68 said:
Hi.
Bought our van in 2017, Aircon worked first year but then the drips appeared on the drive and cost of repair made me put the whole thing on the back burner. In summer last year I took a gamble in buying the blanking plate from BMR and getting my local garage to fit and regas. Bit was I think, £40 and the garage charged £125. To my delight the 'op' was successful which slightly surprised me as the Aircon system had been unused and empty for a couple of years, I was expecting dry or perished seals. It throws nice cold air through the face level grills so all good. Not sure fully what it's like in back but it must have some effect. Result is a happy bunny and saving of a great lot of cash. And, many thanks to BMR.
Click to expand...
Cool, thanks for the info. I’ll get one fitted ASAP. Now to see if I can find a discounted re gas....
 
Hi
My rear air con pipes have sprung a leak. I've bought the blanking plate from BMR but I was just wondering how difficult it is to fit?
Thanks
Phil
 
Happened to be under the car today, having driven it 150 miles yesterday in the pouring rain. I noticed that the piece of foam that blanks the access hole into the box that covers the connection to the rear evaporator was dripping wet.

I suspect this is probably the culprit for the corrosion, the rest of the insulation (that runs the whole length of the pipe) is closed cell foam and doesn't hold water but this last little piece is open cell foam and clearly gets saturated by spray from the rear wheel. You can see the difference in appearance in this picture.
https://imgur.com/YzCN5eZ
Aluminium getting wet isn't usually a problem, the exposed section of this pipe will get wet with condensation during normal operation.
But salty water, ie road spray in the UK during the winter, is a real problem as it strips off the oxide layer and causes pitting.

If your rear pipe is still intact I would suggest removing the box, sliding this bit of foam back and painting the section of pipe underneath it with a corrosion inhibiting paint. I don't think removing the foam will help significantly as it stops spray getting into the box so you'll just move the problem.
 
Great advice. Gave mine a liberal dosing of Owatrol when I first had it. Probably needs doing again.
 
cjholding said:
Happened to be under the car today, having driven it 150 miles yesterday in the pouring rain. I noticed that the piece of foam that blanks the access hole into the box that covers the connection to the rear evaporator was dripping wet.

I suspect this is probably the culprit for the corrosion, the rest of the insulation (that runs the whole length of the pipe) is closed cell foam and doesn't hold water but this last little piece is open cell foam and clearly gets saturated by spray from the rear wheel. You can see the difference in appearance in this picture.
https://imgur.com/YzCN5eZ
Aluminium getting wet isn't usually a problem, the exposed section of this pipe will get wet with condensation during normal operation.
But salty water, ie road spray in the UK during the winter, is a real problem as it strips off the oxide layer and causes pitting.

If your rear pipe is still intact I would suggest removing the box, sliding this bit of foam back and painting the section of pipe underneath it with a corrosion inhibiting paint. I don't think removing the foam will help significantly as it stops spray getting into the box so you'll just move the problem.
Click to expand...

Good advice though I would advise removing the flap entirely. Without the flap the foam isn't necessary to protect the pipe from touching the flap.

As said, aluminium getting wet isn't a problem... but even without salt if the aluminium has an electrical connection to steel and water is present between them there will be galavanic corrosion, one metal acts as an anode and the other acts as a cathode. There is certainly an electrical connection and the rear AC evaporator will make water present (when AC is on) even on a hot sunny day.
 
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cjholding said:
That's probably not a bad idea, but you will need to treat all the the exposed aluminium.
Click to expand...
Of the 4 Elgrand front to rear AC pipes I have changed by dropping the back axle I did paint the exposed aluminium pipe in the only usual place where they rot which is the area around the foam that you mentioned on all 4.... But I think there's no real need to treat/paint it, after all this is the only area the aluminium pipes rot even though there are other exposed bits of aluminium AC pipe (which don't seem to rot) and I reckon they rot at this position due to galvanic corrosion... Galvanic corrosion which is prevented as soon as the damp foam between aluminium and steel has been removed.

Salt may be a problem but a far lesser one imho... All the under-car AC pipes have exposed (bare aluminium) joints at the front end of the car but they don't seem to get corroded, I reckon because they don't have damp foam sandwiched between them and the steel body. The AC pipes rot in Japan where they don't use salt on roads, though salt will make it worse not least by increasing the galvanic effect by increasing the effectiveness of the electrolyte (adding salt to water). Effectively (to use the same word again) the aluminium and steel form the anode and cathode of an electronic cell (battery) and the battery is shorted out because the aluminium AC pipes have a very good electrical connection to the steel of the car at multiple points. In such cell/battery the anode (aluminium AC pipe) loses mass as it is eaten away and some of it coats the cathode (steel of the car). Disconnect the electrical connection or remove the electrolyte (damp foam) and the process stops so you don't get holes in your AC pipes... and since we can't disconnect the electrical connection it makes sense to remove the foam but you don't want to remove the foam if the steel flap is still in place...

Other cars have the same type of AC pipe corrosion problems... always where the aluminium pipe is close to the steel body of the car and water is present. Like on Pug 306's where the front AC pipe is held closely to the steel front end of the car by a narrow bit of rubber. On the 306 the 'proper' fix involves changing an AC pipe that runs all around the engine bay to low down on the front bottom chassis crossmember to the condensor at the front and the same length of AC pipe runs through the bulkhead to behind the dashboard so is expensive for both the long AC pipe and in terms of labour (dashboard out job to replace), I once fixed one by fixing the galvanically corroded section over the low on the vehicle chassis member area using parts sourced from a hydraulics pipe firm.
 
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Surely someone could source the correct bore pipe and make these to suit?
I'm pretty handy with a pipe bender. Where would you get the raw pipe from?
 
if i remember correctly they are double skinned
 
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