>>>*Many modern engines are bimetal, which means they have aluminum heads on cast iron blocks.
This is a fine way to create electrolysis, and the cause of corrosion of the aluminum material. This normally shows up around the coolant jackets but note the condition is throughout, if you see it, the head is likely junk.
Weld away if you like but I have sliced them into sections, corrosion once initiated will destroy the casting.
Avoid pure aluminum replacement heads as they will contain no silicon, (normally 8%) or fine copper grains in the alloy to resist corrosion. There are a BUNCH of them coming into the USA now, the prices are attractive. I would expect to see corrosion in 2-3 years with any pure aluminum head produced from recycled material. You DO realize why the price of scrap aluminum is so high, don't you?
*So I sit here with around 100 heads in stock grinning because I happen to KNOW what the future market is....*LOL**
*Yep, evil <img src="/forums/images/graemlins/evil.gif" alt="" /> capitalist here...heehee.
If rebuilding, install bronze freeze plugs, NEVER use galvanized or steel. Bronze might turn black on the inside but it will never corrode! Galvanized? Well, you aren't rebuilding a battery, are you?
Yes, distilled water, NOT filtered. Some areas of the country are of no concern, for example, use water from the Bull Run watershed here in Portland with no worries. In the summer when they go on ground wells, don't even think of it. I won't even drink that stuff, let alone put it in my vehicles.
*Bottled water? K....WHERE do you think they GET that?...*LOL**...odds are high your tap water is cleaner..I put bottled water in my Camaro one day when I had an upset, I am STILL trying to get the crud out of there, even a flush didn't get it all.
Here is one fine example: I rebuilt a 22RE head for a customer, it was in perfect condition, it was washed, the seats/valves machined and fitted, and new seals installed.
He bolted it on, filled it with plain water, started the engine for a warmup, all was fine. Summertime, no worries about freezing.
Three months later the customer restarted the truck and didn't make it to Scappoose, a 7 mile trip. He brought the head to us madder than a hen with her eggs swiped, I looked and my jaw dropped, it was junk, corroded out in several places.
In just 90 days!!!!
Now I had that exact same head in my HANDS just 3 months before. Right in my dang HANDS!!! No crew to be suspicious of, did it myself! But the customer KNEW he had driven it only a dozen miles, and I happened to know the guy, he would NOT lie to me!
Go ahead and explain to me how I explain to the customer what that problem is? I will tell you what I did, I grabbed a brand new Pro head off the shelf and handed it to him.
Then as he stood there holding it I gave him one of my little lectures.
Turns out the water supply in Scappoose, Oregon is very high is sodium(salt), he was on what is known locally as Dutch Canyon water.
Three months, sitting parked destroyed his rebuilt head.
Yes! Use the factory suggested coolant, IN the concentrations suggested. It is expensive.
It is cheap....One to trust me on, this is one area where the factory is correct. Dealerships buy from me daily, timing sets, covers, on and on. But on the right coolant formulated for the vehicle, use what they suggest. The price is cheaper in the long run.......*EB
