Thanks for the great info! I wonder if the elements (Chlorine etc) in our drinking water in South Africa is not condusive to creating a galvanic situation in the cooling system and Bob's suggestion to use distilled water is not the way to prevent any chemical cocktail from forming!
Our water quality is reducing by the day with raw sewerage being pumped into our rivers!!! Sticking to beer! ----- Original Message ----- From: Granite City Performance To: The Chevelle Mailing List Sent: Monday, July 13, 2009 4:49 AM Subject: Re: [Chevelle-list] chrome thermostat housing (water outlet) Pewter? I don't think so. Pewter is comprised of 85% to 92% tin which is corrosion-resistant. It's most likely made from what is commonly referred to as "pot metal" a low-grade alloy made up of zinc, aluminum and other metals. It's great for making lots of cheap castings for next to nothing but can be prone to instability over time, especially in an elevated temperature, corrosive environment. Brass, which is an alloy of copper and zinc, is very corrosion resistant to atmospheric, water and many salt-water conditions but bronze, with it's higher copper content, is more corrosion resistant than brass. Galvanic corrosion is probably a car cooling system's greatest enemy. Not only do you have to consider each material's physical characteristics but you have to reduce the electrical potential between the two metals. By using 2) electrochemicaly dissimilar metals (aluminum and brass), an electrically conductive path between the two metals (the chassis) and an electrolyte to allow the flow of metal ions (water & coolant), you create a galvanic cell. The galvanic corrosion rate depends on the electrical potential between the two metals; zinc and aluminum (pot metal) being the most reactive, then iron (your cylinder block), chromium alloys - including chrome plated materials as less reactive, then brass, copper, nickel and stainless steel as the least reactive. Corrosion inhibitors (Bar's Leak) can be added to the system and will slow-down but not eliminate galvanic corrosion. To reduce galvanic corrosion it is recommended to use the same material (or materials with a similar electric potential) throughout out the cooling system and ensure other components (plumbing & connectors) do not introduce a reactive metal into the system. I know, I know... blah-blah da blah, blah, da blah. --Don : G r a n i t e . C i t y . P e r f o r m a n c e : custom engineered competition components http://www.granitecityperformance.com/ From: Johann Grobler Sent: Sunday, July 12, 2009 7:21 AM To: The Chevelle Mailing List Subject: Re: [Chevelle-list] chrome thermostat housing (water outlet) I spoke to my friend Joe and he informed me that the chrome housing that packed up was made from Pewter, that is why it rotted! He is casting new ones from brass! No more rust. Can also be chromed or polished to a high shine! ----- Original Message ----- From: "Bob Haggard" <[email protected]> To: "The Chevelle Mailing List" <[email protected]> Sent: Sunday, July 12, 2009 12:13 AM Subject: Re: [Chevelle-list] chrome thermostat housing (water outlet) >I think that using distilled water with your antifreeze helps stop >corrosion and maybe waterpump lubricant may help too. I had alway heard >the same thing about the cheap chrome waternecks but I used one for years >and when I removed my 283 and sold it, the thermostate housing still looked >like new. The cast iron one that was on my Buick 350 looks like it was >left in a bucket of salt water for years and water pumps will spring a leak >too so cast iron has it's problems too. > Just a thought but I agree and I would not use one again. > Bob Haggard > > ---- Larry Williams <[email protected]> wrote: >> Made in China!? I have the used the same cast iron housing since 94. >> >> John Nasta wrote: >> > Just a little caveat emptor... When I built the engine for my El >> > Camino 4 or 5 years ago, I put one of those shiny chrome thermostat >> > housings on it. It rotted from the inside and developed a hole, which >> > caused a bad leak. Today I bought the good old fashioned cast one and >> > the walls of it are substantially thicker. I was lucky not to get >> > stuck somewhere. I first noticed it when I was just moving the car >> > from one side of the street to the other for parking regulations. >> > >> > ------------------------------------------------------------------------ >> > >> > >> > No virus found in this incoming message. >> > Checked by AVG - www.avg.com >> > Version: 8.5.375 / Virus Database: 270.13.8/2227 - Release Date: >> > 07/09/09 05:55:00 >> > >> > > >
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