Dear List, Unlike some folks on the Samba who like to speculate and draw conclusions from late night reruns of Mr. Wizard's World or howitworks.com I usually try to research things that I am interested in a little better. One of the ways I do this is by going to an actual professional in the field and asking them a few questions. I feel that these folks know about this issue much better than we ever could since the company that they work for has invested millions of dollars in research and thousands of man hours in studying these issues. After the discussion from thesamba about long stainless steel pipes leaked onto this forum (pun intended) I took it upon myself to write a letter to the folks at Prestone to see what they would have to say on this matter. Here is what I wrote and also the response from Prestone tech person. No animals were injured in the writing of this email: Dear Prestone folks, I have a question about using your antifreeze in a coolant system with many different types of metal. I currently run an automotive repair shop where we deal with Volkswagen Waterboxer engines. These are older engines from the 80s and 90s, and since they are a flat four type of engine the coolant system consists of a blend of aluminum, magnesium, steel, cast iron, brass, rubber, and plastic. Lately we have been replacing some of our coolant pipes with stainless steel so that is in the mix as well. Many people tell me not to use the stainless steel pipes in the coolant system because stainless steel has a high galvanic voltage and this is going to cause more corrosion on the inside of the engine or in the cooling system. I feel that if you have a good antifreeze, like your Prestone product, and you replace it every few years with fresh coolant, that it doesn't matter what the galvanic voltage of the different metals are, the antifreeze will keep the engine from corroding on the inside. Since you folks have obviously done millions of dollars worth of testing on this subject I thought I would ask your opinion on the subject. Do you think there is any validity to the idea that using stainless steel coolant pipes in a coolant system is going to cause any more corrosion issues if the antifreeze is good and working properly? I await your advice and help Ken Wilford _Response:_ Dear Ken, Thank you for contacting Prestone. Modifications of the original system could cause unintended problems and should be monitored closely. In general, if they are not in direct electrical contact (e.g., physically in contact) with other metals, stainless steel parts in engine cooling systems are typically quite harmless and will not cause galvanic corrosion of other metals. Due to its high resistance towards corrosion, stainless steel tends to generate little or no corrosion. If a stainless steel pipe is used to replace a coolant pipe that is made of a different material in the engine cooling system and the stainless steel pipes are in direct physical contact with other metal parts, galvanic corrosion may occur. The extent of the galvanic corrosion and whether the corrosion damage is observable depend on system conditions and coolant corrosion protection performance. If stray current corrosion conditions are not introduced by the installation of the new stainless steel pipe, and the coolant corrosion protection performance is not compromised (e.g., good quality coolant is in use), excessive galvanic corrosion of the parts made of metals such as aluminum alloys, carbon steel, and cast iron in contact with the stainless steel pipe is unlikely to occur. We also apologize for the delay for any inconvenience this might have caused. Regards, Jake Mathews Prestone Technical Services
You can gather from this what you wish. To me it seems to say that unless a stainless steel pipe is in direct contact with an aluminum part, then corrosion is very unlikely. Also, even if this is the case, if you have good antifreeze in place, this should stop this from happening. Of course you should continue to monitor the state of your cooling system and refresh your coolant at regular intervals. That is just good PM. Hope this helps. -- Thanks, Ken Wilford John 3:16 www.vanagain.com Phone: 856-327-4936 Fax: 856-327-2242 |
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