Aluminium engine and eletrolysis - potential for problems
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Joined: Jun 2013
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From: Brazil
Aluminium engine and eletrolysis - potential for problems
Dear all, our cars all have aluminium engine and radiators, so must of us already discovered the effects of eletrolysis in our cars, what means, lots os small leaks in several different spots in the car with no aparent reason. Just saw this very interesting articke about it, and decided to share, to be one more of our DYI monthly activities.
http://www.sancarlosradiator.com/electrolysis.htm
Anyone here already had this kind of problem, is this very commom in our 928's?
Hope this is usefull.
Best,
G.
http://www.sancarlosradiator.com/electrolysis.htm
Anyone here already had this kind of problem, is this very commom in our 928's?
Hope this is usefull.
Best,
G.
Thread Starter
Instructor
Joined: Jun 2013
Posts: 113
Likes: 1
From: Brazil
On my hot-rod, with an iron engine and brass radiator didnt have a lot of problems in the last few years. Replacing this radiator for a Aluminium one was enough to understand what eletrolysis can cause. The cooling liquid transforms into a acid mixture, just like in our car bateries, and corrodes everything, starting with aluminium the softer metal there. The "new" radiator was destroyed by eletrolysis in less than 1 year. Ground also has a major effect on this...Will check all cars during weekend, hopefully can avoid more problems ...$$$$
Three Wheelin'
Joined: Apr 2011
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From: Singhampton, Ontario/London, Ontario
Before it can eat stuff up the pH level has to degrade to 8 or lower for it to be a problem. Just change your coolant at regular intervals. The additive package is what makes modern coolant last as long as it does without eating stuff up, but it breaks down like anything given time. Fresh coolant generally has an alkaline pH value of 9-10. This isn't the only way to determine when it should be changed, but it correlates fairly well with the rest of coolant wear.
As far as how common it is for this to cause problems. I have heard that many 928's that have been sitting for a while turn out to have leaky heads from corrosion when they start being driven again, but that's about it really for what I've heard about.
As far as how common it is for this to cause problems. I have heard that many 928's that have been sitting for a while turn out to have leaky heads from corrosion when they start being driven again, but that's about it really for what I've heard about.
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There's a certain amount of fear mongering at that website. We know San Carlos Radiator, and they know the 928, or did. They were Devek's go-to subcontractor for cooling system and AC work way back when.
At a macro level, a lot of the concerns shared on that site are valid. Some of their recovery methods are a little far out there. I suppose one could pour a bit of amine into the system to build a "protective" layer of aluminum hydroxide on the aluminum surfaces. But that adds an insulating layer that strips off handily when the coolant does deteriorate to less than 7.4pH. So rather than trying to neutralize or buffer a spent coolant mixture, it's really better to replace it, in my opinion anyway.
Adding zinc sacrificial anodes has been discussed. They need to be immersed in the coolant to be effective, so the typical radiator-cap mounted anodes are not long enough. And they are only effective when the coolant pH is too low, something we avoid with regular coolant services and good pure dilution water.
At a macro level, a lot of the concerns shared on that site are valid. Some of their recovery methods are a little far out there. I suppose one could pour a bit of amine into the system to build a "protective" layer of aluminum hydroxide on the aluminum surfaces. But that adds an insulating layer that strips off handily when the coolant does deteriorate to less than 7.4pH. So rather than trying to neutralize or buffer a spent coolant mixture, it's really better to replace it, in my opinion anyway.
Adding zinc sacrificial anodes has been discussed. They need to be immersed in the coolant to be effective, so the typical radiator-cap mounted anodes are not long enough. And they are only effective when the coolant pH is too low, something we avoid with regular coolant services and good pure dilution water.
Thread Starter
Instructor
Joined: Jun 2013
Posts: 113
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From: Brazil
Guys, thank you for the replies, I agree that the website exagerates in the fear factor, but it seems to be spread in the internet. The fact is that I just lost one radiator to eletrolysis, but in this case the engine was all iron, what I believe its terrible (different material), and i really didnt follow the recommendations on the cooling aditives as I should. And I believe radiator is the least of my worries...at least is easy to replace. My worries are more towars heads and specifically for 928, the A/C heater under the dash (as you may imagine, we dont use heaters a lot in our cars in Brazil), as the leaks seems to be a nightmare. Thank you all guys. Best. G.
Three Wheelin'
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From: Singhampton, Ontario/London, Ontario
If there's corrosion in the heads already there's nothing really you can do to help that. In fact sometimes with that stuff it's better to just leave the heads alone, you can create bigger leaks once you pull them off and disturb all the crud that's plugged everything up over the years. Same concept as with automatic trannys, if it's past a certain mileage changing it could do more harm than good! Ran into that issue with my Dad's 2000 528i with the GM 5 speed, it was at that crucial mileage but when I saw how the fluid looked I left it alone. You can just bypass the heater core as I'm sure many here have done.
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Sounds like the sky is falling after I read this. Electrolysis is governed by laws of chemistry, not physics. If they are going to engage in a scientific discussion about why it is a problem the vendor needs to get the fundamentals correct. If you change your coolant as instructed by Porsche you are keeping corrosion to a minimum and can expect years of service.
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I was taught that water isn't safe to drink unless diluted with alcohol, seems to work.
Generally good coolant seems the right answer, but what about the use of stainless steel bolts vs zinc or cad plated? I'm thinking I bought stainless for a water pump replacement, but I don't recall if they got used. Pretty sure they did on the water bridge.
Generally good coolant seems the right answer, but what about the use of stainless steel bolts vs zinc or cad plated? I'm thinking I bought stainless for a water pump replacement, but I don't recall if they got used. Pretty sure they did on the water bridge.