Lower water pump bolt

[51 MERC-CT]

These bolts were installed ( appox, 4 years ago ) using what were thought to be cad. plated lock washers but were actually stainless steel.
Perfect example of the result of galvanic corrosion.

[V8COOPMAN]

Obviously a good thing you didn't wait five years! DD

[Ross F-1]

Do you run antifreeze?

[39topless]

Wonder if hard rubber washers would work better?

[Walt Dupont--Me.]

Looks like the lock washers stood up, why didn't they use stainless bolts. Walt

[19Fordy]

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Originally Posted by Walt Dupont--Me.

Looks like the lock washers stood up, why didn't they use stainless bolts. Walt

Good question? S/S bolts and washers are the way to go, I think.

[V8COOPMAN]

Originally Posted by 39topless

Wonder if hard rubber washers would work better?

Ya think? How 'bout stainless bolts with the requisite Nev-R-Seize? DD

[51 MERC-CT]

Originally Posted by Ross F-1

Do you run antifreeze?

Originally Posted by Walt Dupont--Me.

Looks like the lock washers stood up, why didn't they use stainless bolts. Walt

Originally Posted by 19Fordy

Good question? S/S bolts and washers are the way to go, I think.

Originally Posted by V8COOPMAN

Ya think? How 'bout stainless bolts with the requisite Nev-R-Seize? DD

If the bolts were stainless this would still set up a situation for galvanic corrosion between the bolt and cast iron. If it were a situation where every thing is dry there is no problem. In this case it is immersed in a 50/50 water/ anti-freeze solution which is the catalyst to start corrosion.

[39topless]

Just removed this bolt from my water pump. It looks fine. I don't use any anti-freeze. Car always in garage.

[scooder]

51Merc,
Those bolts look worse than most of the lower water pump bolts I've pulled out of rusty rancid old flatheads! I thought anti freeze had corrosion inhibitors in it?
Martin.

[51 MERC-CT]

Originally Posted by scooder

51Merc,
Those bolts look worse than most of the lower water pump bolts I've pulled out of rusty rancid old flatheads! I thought anti freeze had corrosion inhibitors in it?
Martin.

Corrosion inhibitors I don't believe would not do anything to prevent galvanic corrosion which is caused by two dis-similar metals. In this case a stainless washer. If the washer was a non stainless one the problem would for the most part, not happen.

[51 MERC-CT]

Originally Posted by 39topless

Just removed this bolt from my water pump. It looks fine. I don't use any anti-freeze. Car always in garage.

Bet if you install a stainless lock washer, after a period of time it would look just like the ones I removed.

[39topless]

Originally Posted by 51 MERC-CT

Bet if you install a stainless lock washer, after a period of time it would look just like the ones I removed.

Thanks for the advice. I believe I will not be installing a stainless washer.

[flatheadmurre]

Time to add a zink anode to the cooling system

[Mike in AZ]

if there is galvanic action between cast and stainless steel, why aren't the stainless lock washers affected?.....they look pretty good compared to bolt head....Mike

[V12Bill]

I have removed several water pumps that Henry installed and they were regular steel bolts. Although you would think that they would rust badly, I never had a problem with Henry's bolts. I guess Henry knew something about rust that we hadn't thought of.

[34PKUP]

Originally Posted by flatheadmurre

Time to add a zink anode to the cooling system

A zink anode will only sacrifice itself to any impurities in solution and will not have any effect on the galvanic corrosion between two dissimilar metals in direct contact with each other.

[39topless]

Originally Posted by 34PKUP

A zink anode will only sacrifice itself to any impurities in solution and will not have any effect on the galvanic corrosion between two dissimilar metals in direct contact with each other.

Do we have an old high school chemistry teacher here? Now the nightmares will start again.

[51 MERC-CT]

Originally Posted by 34PKUP

A zink anode will only sacrifice itself to any impurities in solution and will not have any effect on the galvanic corrosion between two dissimilar metals in direct contact with each other.

Yep, that's the way I understand it to be.

[Steve Staysko]

There are 3 conditions that must exist for galvanic corrosion to occur.
1) There must be electrochemically dissimilar metals present.
2) There must be an electrically conductive path between the two metals
3) There must be a conductive path for the metal ions to move from the more anodic metal to the more cathodic metal
If anyone of these 3 conditions does not exist, galvanic corrosion will not occur.