Rusted Coolant pipes near engine question.

[JoshG]

I just replaced a section of one of the short steel pipes that runs behind passenger side rear wheel. It sprung at least three pinhole leaks. It was very rusty on the outside, BUT I also noticed that there where rust spots on the inside as well. It was clearly rusting in both directions. The pattern on the inside was quite different from the outside rust but it was rust none the less! It was spotted, is the only way I can describe it. Little star like rust spots, most likely from metal deposits catching on the side walls. I removed a section and patched it with some extra coolant hose I had from another car. I see no good reason why these sections need to be metal! (let the debate rage on).

[Bercilak]

[Jake de Villiers]

[jwallis]

I guess I'll go over them with a hammer or probably just pull them and check them when i do the drain/refill i'm going to have to do anyway (for other coolant fixes). i'd hate to do the hammer test, determine it solid, but knock a chunk loose and have it bounce around and plug the radiator or something else down the line...

[Bercilak]

[Terry Kay]

The interior pin holes are primarily caused by electroletical corrosion, inspired by a no coolant servicing issue.
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T.K.

[Jake de Villiers]

[Terry Kay]

It's like an acid burn--
Not the same, but after running a fluid that is supposed to have anti corrosive additives in it to prevent this sort of phenomina--eventually the weakest spots that have been getting thin--in years, and as a result of no , or poor servicing, will let loose, & leak.

Steel or iron engine sleeves will get the same treatment after awhile too--
The sleeves are big magnets to this sort of corrosion too after a life of no coolant servicing .
_________________
T.K.

[jwallis]

[Bercilak]

I apologize, I couldn't easily find the pix last night. A more determined search will happen when I have time.

The section I removed was from the pipes under the back half of the van. The pipe had already dropped down from engine input/output level to flat run under the body.

I removed the section from the bottom of the "S" bend (where it comes down to the lower level) to about 1 foot from the fuel pump.

The major leaky spot was closer to the bottom "S" bend, but there were corrosion points all the way along the seam. At the time, TK suggested that if the corrosion was bad enough to leak at one point, fix that point was just a short term fix, as corrosion was occurring elsewhere too. That opinion was born out by my inspection of the cutout section.

When I later removed the whole set of pipes, I don't recall that I had the time/inclination to check them out end-to-end, but I do know that the ends of the coolant pipes were in good condition. The real problem was corrosion along the seam, and I can't say that closer to the engine was particularly bad, at least based on my semi-interested inspection.

As I said, I'll keep looking for the pix. I threw out the pipe section about 6 months ago, after keeping it for awhile. Now I wish I had it...

rats.

******************************
Question for TK ~

Does regular (say 2 year interval) coolant service avoid this problem, or just slow it down so much that the car self-destructs before the corrosion can become problematic?

Thanks,

B.

[jwallis]

Thanks again Bercilak. Don't trouble yourself for the pics. I will try to find any signs of corrosion and check them out. I'm a relatively paranoid person (since i'm about to spend the next few months travelling) but I still think my pipes are good for a while longer. No one in central Texas uses salt, I did do the heads but the pitting wasn't very bad, so hopefully the coolant was changed on a semi regular basis. I'll definitely keep an eye on them of course...
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[Terry Kay]

<<Does regular (say 2 year interval) coolant service avoid this problem, or just slow it down so much that the car self-destructs before the corrosion can become problematic?>>

Yes.
And this is assuming that the Van is just a play toy, and you don't put that many miles on it.
Every other year would be a very good rule of thumb target coolant service date.

I've mentioned a real easy process many times here and other places of water cooled Vanagon interest.
A simple litmus paper test will tell you if your coolant is good or bad by the color of the test strip.
Simple , easy & a real fast way to test the condition of your coolant.

Once a year dip of the paper in your expansion tank would be a good thing to do--just for grins anyway.
_________________
T.K.

[Bercilak]

TK,

Thanks ~ I'll dig that up (I know I've read that post before) and file it away for reference.

Appreciate your insight,

Best,

B.

[Mellow Yellow 74]

Just read this thread and yes dissimilar metals can cause galvanic corrosion but the two metals need to be in contact.

It's like a battery where you have an anode, a cathode and an electrolyte - when the anode and cathode have an electrical circuit, the cathode will dissolve and will be deposited on the anode.

But if the battery is not connected, nothing happens so as long as your stainless coolant pipes are insulated from the engine and radiator via the rubber hoses nothing will happen.

[Multiman mv]

[flyboyaviator]

Best way to check the plastic pipes for condition, and where is the problem areas. The more I read about replacing them the more confusing it becomes.

[Mellow Yellow 74]

[zuhandenheit]

I just want to report my experience with rusted coolant pipes. I have an 82 diesel van. It sat for a few years while I was doing body work and installing an AAZ engine. At the end of my first road trip, I overheated on the highway and discovered a coolant leak above the fuel tank. I spent a really damn long day in the parking lot of a FLAPS, dropping the tank and cobbling together a fix for a pinhole leak in the pipe. (I got some coolant hose of the correct diameter to fit over the pipe, like a sleeve, and I covered the thing in hose clamps -- like just back to back! -- terrified that it would come loose somehow.)

Anyway, I was lucky that my new engine wasn't damaged! Now I have stainless pipes.

Given the danger of this particular sort of failure, which not only is a nightmare to repair on the road, but can cause major engine damage, and, further, the near-impossibility of evaluating the condition of the pipes -- given the fact that they can rust from the inside out -- I don't think I would ever again want to take a trip running stock metal pipes!

[Vanagon Nut]

[zuhandenheit]