Sacrificial Anode Placement?

My Al heads (on an Fe block) needed to be resurfaced after only 15K miles. There was very slight pitting as a result of corrosion.

I am told that I need a zinc anode to prevent this. My questions, do I need an anode in EACH head? Do I even need to put it in the head? Would I be fine just sticking one in the radiator?

The reason I ask, the 3/8 NPT holes in my heads would only allow me to use an anode that is about 1/2" deep max (so I'd have to cut one to fit) while I could use a 2" anode in the radiator.

Just get a rad cap w/ anode and be done with it.

Radiator is fine. It replaces the drain cock hub.

Not all rads have a drain petcock, so this is easier:

Will the cap style work in the surge tank set-up? Ie: does there always need to be contact with the coolant, even when the engine is off? Sorry Enkeivette...I was going to ask this in a new thread, but thought you wouldn't mind if I asked here.

Yes, there has to be contact with the coolant (as that's the electrolyte), it won't work if it just hangs in there dry.

Haven't been able to find one of those caps at Summit or Jegs. But I do have a drain plug, and the one that goes in there is only $9.

Hey Bird, do you know where you can buy DexCool around here? Don't think I've seen it at the local auto parts stores.

I have 2 unopened gallons in my garage. Prestone Dexcool, GM approved. I run it in the Silverado. When I changed the water pump at 90,000miles, I had ZERO corrosion.

Rodriguez Brothers on Anaheim Blvd. by North street sells it. $12.60 gall.

Top's Auto on Lincoln by Euclid has the rad cap anode just so you know.

I hear they have had a few failures. Don't know if it's true.

enkeivette said:

Haven't been able to find one of those caps at Summit or Jegs. But I do have a drain plug, and the one that goes in there is only $9.

Click to expand...

The pic came from jegs:

http://www.jegs.com/p/Ve-Labs/874787/10002/-1/10125

Dexcool? DON'T DO IT!!!!!!!!!!!!!!!!!!!!!!

Don't do it?! Why not?

Everyone else is telling me that this is a fix for the corrosion problem.

It is not, from what I have read recently it's great for corrosion inhibition when the jaackets are fully submerged, however when they are not due to coolant loss (whichever way that may happen) the non submerged jackets will start to corrode quickly.

The difference is that dexcool uses organic acids for rust inhibition, more traditional coolants use anorganic salts (borate, silicate, phosphate)


OOPS

http://www.imcool.com/articles/antifreeze-coolant/CPM-52-DEXArticle-Excerpt.pdf

Twin_Turbo said:

Dexcool? DON'T DO IT!!!!!!!!!!!!!!!!!!!!!!

Click to expand...

Marck, The newer Dexcool is fine. (IMHO)I will post pictures of my 5 year old, 90,000 mile water pump. It's pristene inside. There may be more to it than I know, but when I changed that pump out I was highly impressed by how clean it was inside.

Twin_Turbo said:

It is not, from what I have read recently it's great for corrosion inhibition when the jaackets are fully submerged, however when they are not due to coolant loss (whichever way that may happen) the non submerged jackets will start to corrode quickly.

The difference is that dexcool uses organic acids for rust inhibition, more traditional coolants use anorganic salts (borate, silicate, phosphate)


OOPS

http://www.imcool.com/articles/antifreeze-coolant/CPM-52-DEXArticle-Excerpt.pdf

Click to expand...

I must admit the truck has an expansion tank not unlike the older C-3's, and not an overflow or recovery tank.