Club 80-90 Forums

I think I caught this just about right lol good job I wasn't on my hols somewhere in Europe isn't it..





Could be a timely reminder for others to have a close look at their metal coolant pipes (mines a 2.1 wasserboxer)

Martin

Lucky !

When I was doing my pre-MOT check round the engine bay I noticed ours had gone exactly the same, fortunately I had one in stock ... stainless though next time methinks.

Ian

indeed its is common, and nearly always on the bit you cant easily see......

it pays to keep a close eye on them, and keep a spare in stock as Ian says....

On my old van when I removed the engine I found loads of car filler round that area. I had driven all over the place with it like that for a few years.

jed

Another bit of vw's great cooling system design! Glad you found it before an epic fail!

Not a good idea ian.Dont know if you remember some time back there was a thread about using the stainless front to rear pipes.Someone said this would cause corrosion(steel touching stainless steel) as this would have a battery affect.(i think that was the term used) I got in touch with a guy at birmingham universitys metallurgy dept.Who told me this affect would only happen if the two metals came into contact with each other.

stainless though next time methinks.

Same pipe I just changed yesterday...

Mine'd gone on the lower front corner. The whole of the rest of it looked like new, but that one corner was damn near through - a light tap with a screwdriver put a hole about the same size as yours in it...

Don't think it was electrolysis that did mine - the damage was so localised, and on the corner that's above the exhaust and gets road carp thrown right at it. It was also coming from the outside in - on the inside, there were only small scabs of rust starting to come through, but the outside was toast.

Definitely a job for stainless - especially since the two small pipes are available in stainless, so plenty of dissimilar-metal in there already. Also, the pipe's only directly connected to alloy (water pump).

R0B wrote:Not a good idea ian.Dont know if you remember some time back there was a thread about using the stainless front to rear pipes.Someone said this would cause corrosion(steel touching stainless steel) as this would have a battery affect.(i think that was the term used) I got in touch with a guy at birmingham universitys metallurgy dept.Who told me this affect would only happen if the two metals came into contact with each other.

'Electrolysis'. Two dissimilar metals in contact with each other and a liquid/moisture present also http://www.berridge.com/Preventing%20Electrolysis.pdf" onclick="window.open(this.href);return false;

Best get another mild steel one back in stock then

Ian

And therein lies the problem.

Also, the pipe's only directly connected to alloy (water pump).

Pretty sure mine was just rotted from the outside, no internal corrosion. I think these things are just not painted very well and are made from plain old mild steel.
I suppose at 22 years old it's hardly a weakness, only to be expected really. Very glad that I noticed it when I did tho...could have been rather more serious.

Martin

AdrianC wrote: Also, the pipe's only directly connected to alloy (water pump).

It is directly connected to everything by the liquid!!!!!!! Next time you have a bath try dropping a live cable in with you - you will soon see that it is connected to everything.

Tell you what.You try it.And let us know how you go on.

Next time you have a bath try dropping a live cable in with you

R0B wrote:Not a good idea ian.Dont know if you remember some time back there was a thread about using the stainless front to rear pipes.Someone said this would cause corrosion(steel touching stainless steel) as this would have a battery affect.(i think that was the term used)

I thought it as decided that the chances of that were slim as long a you kept up the usual coolant change regime?

The guy at brum univ said to me.Its the metal on metal that will cause corrosion.He said the water flowing through the pipes should cause very little.But hey hes only a metallurgist.What would he know I wish i still had his email to me.As he could explain it better than i.It got lost when i had a computer crash.And had to do a fresh install.