is passanger head coolant plug bolt with zinc coating a bad idea?
01-13-2012, 10:09 AM
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is passanger head coolant plug bolt with zinc coating a bad idea? I must have left the bolt on my old motor when I traded it and now I need another one. I know its m12x1.5x12mm from what I read on here, I went to 3 diff places (lowes,advanced,fastenal) and only fastenal had the m12x1.5x16mm.
I am not sure if the 16mm length will be a problem or not, but besides the length question, my main question and concern is that they didn't have stainless steel. They only carried zinc finish. People add zinc anodes to there cooling system so the coolant will eat the zinc instead of the aluminum. will the zinc coated bolt work in the head or do I have to find a SS bolt?
I am not sure if the 16mm length will be a problem or not, but besides the length question, my main question and concern is that they didn't have stainless steel. They only carried zinc finish. People add zinc anodes to there cooling system so the coolant will eat the zinc instead of the aluminum. will the zinc coated bolt work in the head or do I have to find a SS bolt?
01-18-2012, 12:07 PM
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used that part number and napa doesn't carry it. called dealership and they said the closest one was 4-5 business days to recieve it. I need it asap. anyone know where to get one? maybe another part number from the same bolt on another vehicle?
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01-18-2012, 05:53 PM
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just plug it with a zinc plated bolt and order the GM part. Swap it out in a week. Galvanic corrosion won't happen that quickly.
http://www.corrosionsource.com/FreeC...alvanic+Series
http://www.corrosionsource.com/FreeC...alvanic+Series
01-18-2012, 06:40 PM
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^^ Agreed. Not in a week, but i can if you are in the right environment.
However, here is an explanation.
Cast Aluminum has a galvanic potential of .90V-.95V
Hot Dipped Zinc plating has a galvanic potential of 1.20V
Stainless steel (depending on alloy) has a potential of .50V-.60V
If designing for a normal to harsh environment (High Humidity/salt water areas) you should be within a .25V to .15V potential difference, respectively. If you fall outside of this you can literally eat away the bolt. In this case humidity is the killer, and an oil/suit laden engine may protect slightly from the environments. It is really direct contact with moisture or salt environment that causes quick corrosion.
Long story short, with that said you have better chances with zinc plating when placing this part in an aluminum head. But I would put in the GM part.
A good source is here:
http://www.engineersedge.com/galvanic_capatability.htm
However, here is an explanation.
Cast Aluminum has a galvanic potential of .90V-.95V
Hot Dipped Zinc plating has a galvanic potential of 1.20V
Stainless steel (depending on alloy) has a potential of .50V-.60V
If designing for a normal to harsh environment (High Humidity/salt water areas) you should be within a .25V to .15V potential difference, respectively. If you fall outside of this you can literally eat away the bolt. In this case humidity is the killer, and an oil/suit laden engine may protect slightly from the environments. It is really direct contact with moisture or salt environment that causes quick corrosion.
Long story short, with that said you have better chances with zinc plating when placing this part in an aluminum head. But I would put in the GM part.
A good source is here:
http://www.engineersedge.com/galvanic_capatability.htm
