corrosion around aluminum motor plate coolant holes

Jim B · 10-23-2015, 05:08 PM

Adding a zinc anode in a radiator bung used to be SOP when aluminum cooling system components were used in a cast iron engine environment. Adequate engine grounding is a must. As long as the water is potable (clean tap water quality) and the ph is around 7.0 we never found it necessary to use distilled water to prevent electrolysis.

Tom Goldman · 10-24-2015, 10:10 AM

I see it occasionally on cars in the shop. Usually can be traced to no or inadequate engine grounding. the motor plate should have a ground also.
A little cooling system conditioner dosent hurt either , helps with the Ph level.

Bob Mulry · 10-25-2015, 12:32 PM

Hi Guys,

Just my 2 cents..................

Zinc plates have been welded to the hulls of ships to prevent damage to the steel hull and brass screws by galvanic reaction.....

The more active metal is sacrificed to protect the less active.....

Zinc is a less active metal and unable to protect aluminum....

To prevent galvanic damage to aluminum a magnesium anode should be used....

For additional info I will post a link speaks to galvanic action...

http://www.performancemetals.com/anodes/AnodeFAQs.shtml

Bob

10-23-2015, 05:08 PM	#1
Jim B Member Join Date: Dec 2008 Posts: 100 Likes: 0 Liked 1 Time in 1 Post	Re: corrosion around aluminum motor plate coolant holes Adding a zinc anode in a radiator bung used to be SOP when aluminum cooling system components were used in a cast iron engine environment. Adequate engine grounding is a must. As long as the water is potable (clean tap water quality) and the ph is around 7.0 we never found it necessary to use distilled water to prevent electrolysis.

10-24-2015, 10:10 AM	#2
Tom Goldman VIP Member Join Date: Jan 2003 Location: Allentown,PA Posts: 2,477 Likes: 893 Liked 883 Times in 237 Posts	Re: corrosion around aluminum motor plate coolant holes I see it occasionally on cars in the shop. Usually can be traced to no or inadequate engine grounding. the motor plate should have a ground also. A little cooling system conditioner dosent hurt either , helps with the Ph level. __________________ Tom Goldman 1500 SG , 1506 STK

10-25-2015, 12:32 PM	#3
Bob Mulry VIP Member Join Date: Apr 2002 Location: Coarsegold, CA Posts: 1,016 Likes: 57 Liked 320 Times in 102 Posts	Re: corrosion around aluminum motor plate coolant holes Hi Guys, Just my 2 cents.................. Zinc plates have been welded to the hulls of ships to prevent damage to the steel hull and brass screws by galvanic reaction..... The more active metal is sacrificed to protect the less active..... Zinc is a less active metal and unable to protect aluminum.... To prevent galvanic damage to aluminum a magnesium anode should be used.... For additional info I will post a link speaks to galvanic action... http://www.performancemetals.com/anodes/AnodeFAQs.shtml Bob __________________ Bob Mulry 7516 STK A & M Motorsports