Copper petrol lines reaction

Copper petrol lines reaction

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GreenV8S

Original Poster:

30,721 posts

297 months

Tuesday 18th February
quotequote all
I've been using copper petrol lines for many years without any problems. However, when I took the system apart to replace some rubber connection hoses recently I noticed an unusual yellow coating inside the copper pipes, and in a couple of places it had built up into a lumpy deposit. The hoses that connect to the copper also look slightly yellow inside.

I've never seen anything like this before, but I guess it must be some sort of chemical or electrolytic reaction with the copper. The car is running standard pump fuel. It's been a decade or so since I had the system apart last time, and maybe modern ethanol mixes are responsible somehow.

I'm worried that this sort of deposit could interfere with injectors and pressure regulators and so on, as well as potentially floating around as debris.

Anybody got any idea what's going on? There's no direct metal-to-metal contact between the copper and anything else, but obviously everything is connected via the fuel.

stevieturbo

17,720 posts

260 months

Tuesday 18th February
quotequote all
I've used copper myself, with no issues.

the only one thing I found online, was where a guy had used it in his fuel tank, and it developed a tarnish. But in that case as a pickup tube, it would see fuel, air, fuel, air, fuel, air etc....so I'd guess that is the cause.

But always filled or in contact with fuel.....never had a problem.

Where is the filter located ? before or after the copper line ?

GreenV8S

Original Poster:

30,721 posts

297 months

Tuesday 18th February
quotequote all
The copper is between the tank and the pump.

100SRV

2,243 posts

255 months

Tuesday 18th February
quotequote all
I have copper fuel pipes but haven't seen any deposits like you describe. The fuel is either E10 sometimes with a stabiliser additive or E5.

Lesliehedley

251 posts

273 months

Tuesday 18th February
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This is from Hagerty website discussing ethanol:

Although many cars run E5 without significant problems, doubling the amount of ethanol in the fuel can cause a variety of issues in older cars. Ethanol is hygroscopic, which means that it absorbs water from the atmosphere. And that water, in turn, finds its way into your car. This can lead to condensation in fuel tanks, fuel lines and carburettors and cause corrosion in brass, COPPER, lead, tin and zinc components.


GreenV8S

Original Poster:

30,721 posts

297 months

Tuesday 18th February
quotequote all
Here's a blurry picture of the contamination.


E-bmw

10,752 posts

165 months

Wednesday 19th February
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This will almost certainly be a stupid statement but here goes.

I have just taken early retirement from working offshore & that deposit looks VERY like deposits I have seen on Methanol storage tanks/pipes.

Belle427

10,261 posts

246 months

Wednesday 19th February
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I would guess its moisture content related, probably a garage car too that does not get used much?

GreenV8S

Original Poster:

30,721 posts

297 months

Wednesday 19th February
quotequote all
Belle427 said:
I would guess its moisture content related, probably a garage car too that does not get used much?
Definite possibility. Any idea what it is? You can see the green copper oxide on the outside, which I assume is due to prolonged heat + moisture exposure.

GreenV8S

Original Poster:

30,721 posts

297 months

Wednesday 19th February
quotequote all
E-bmw said:
that deposit looks VERY like deposits I have seen on Methanol storage tanks/pipes.
Hmm. I looked briefly into copper/methanol chemistry, quietly closed the page and backed away.

stevieturbo

17,720 posts

260 months

Wednesday 19th February
quotequote all
GreenV8S said:
Here's a blurry picture of the contamination.

That does look pretty nasty

Jo-say8k

158 posts

29 months

Wednesday 19th February
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Could you take a picture of some on a flat surface please?
I won't be able to solve it but I've seen something similar before and wondered if it might be the same?

Belle427

10,261 posts

246 months

Wednesday 19th February
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Kind of looks like the calcium build up you get in domestic water systems, no idea why though.

SystemOfAFrown

76 posts

33 months

Thursday 6th March
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Copper and other soft metals like Zinc and brass are not compatible with ethanol fuels, especially when water is present.

GreenV8S

Original Poster:

30,721 posts

297 months

Sunday 9th March
quotequote all
SystemOfAFrown said:
Copper and other soft metals like Zinc and brass are not compatible with ethanol fuels, especially when water is present.
That's interesting to know. Any idea what the reaction is?