Recently I bought some of these zinc anodes from Macs, haven't installed them yet. My question is has anyone used them with good results? I guess that's a dumb question because if they work your heads would look perfect. These seem like a great idea but want some opinions before I start draining radiators.
Better to save your money and use good coolant. The theory behind the zinc anodes is sacrificial protection, the zinc will corrode preferentially to the aluminum. But in reality it does not work. Good coolant has corrosion inhibitors that are more effective. Do you have a link for the parts? I could make a better technical reason to show you why they don't work. If they really are needed then why don't OEM's use them in new cars with alum heads?
How does the coolant prevent electrolysis that eats aluminum parts? I'm an old boat guy with a lot of experience replacing zincs. Why is it different with a car?
They have been used in water heaters and marine engines for years. Little hard to run antifreeze through those.
The inhibitors in coolant (EG) are consumed with time and temperature. Here's an explanation how inhibitors in coolant function http://www.lytron.com/Tools-and-Tec...Notes/Preventing-Corrosion-in-Cooling-Systems
Yes and they are called sacrificial anodes. BTW, magnesium also is used as sacrificial anode material. The problem is that the area protected must be electrically coupled to do any good, as in direct metal connection tot he part being protected. Even then there is a limit how far the protection can effect, think of a magnetic field decreases with distance. Same idea for the sacrificial anode. Marine engines always have bad corrosion unless they use a heat exchanger. I asked the OP to give me the link to the parts so i can see exactly how they are used or implemented. If they are the radiator cap things with a piece of zinc hanging down, save your money. As stated the inhibitors are consumed. That is why you are supposed to change out coolant every so often. Not because it loses it's anti-freeze and increased boil temp characteristics. A car is different than a boat because the car is a closed system (for the most part). Unless the boat has a closed heat exchanger the cooling water is constantly new.
Here's a thought for you. Any type of coolant that flows through any rad or heater core will create a small electrical static charge as it flows through the system. If the rad (or heater core) is totally isolated from the chassis or any other source of ground (think rubber hoses or mounts or both), then that small static charge can and will create corrosion in any system alluminum or copper. Stray electrical current from something else in the car that is poorly grounded can also find it's way into the cooling system and cause electrolysis, Case in point. I had an OT daily driver, an 88 Ranger pickup. The small heater core was isolated in the heater housing which is all plastic. It sprung a leak so I replaced it with a good quality new one. 6 months later antifreeze dripping on the floor again. WTH ?? Replaced it again, you can guess what came next. Right another heater core. Only this time I had done a little research and when I installed the new one I soldered a small machine screw to it and ran a wire from the screw to the metal body of the truck as a ground. Drove the truck for 4 more years and never had any more trouble. I think a good idea is to ground your rad, aluminum or copper.
Why would you want to add any unsprung weight with these anodes on you cars? They gotta be really heavy and cause some serious speed wobble at anything over 15mph.(inside joke here fella's)
So, what you're saying is you grounded the heater core. Aluminum heads are grounded by the head studs but most of the old ones we see are corroded. Again, the first question, how does coolant prevent damage to aluminum parts and why won't zinks help prevent it?
"Regular" anti-freeze is ethylene glycol. Ethylene glycol is corrosive, especially to aluminum. Anti-freeze has corrosion inhibitors that prevent corrosion, and also prevent the ethylene glycol from attacking the metals it contacts. When the corrosion inhibitors in anti-freeze are defeated beyond a certain point the ethylene glycol will cause corrosion. Tests can be done to determine the state of the corrosion inhibitors. Additives are available to replenish depleted corrosion inhibitors. In normal use, changing the anti-freeze every two years is enough to avoid corrosion problems. Early "permanent" anti-freeze was not inhibited for aluminum. Special(and expensive) aluminum friendly anti-freeze had to be used back then. Non-permanent anti-freeze was methanol. Methanol is very corrosive to aluminum. Working on old cars I have seen corroded parts that I'm sure were damaged by early anti-freeze not suitable for aluminum. Plain water also promotes corrosion. Depending on the water, its tendency to corrode can vary quite a bit. Even when running plain water it's best to use a corrosion inhibitor additive.
I'm not sure that you could buy an antifreeze w/o inhibitors. I've used Prestone for 20+ yrs w/ no issues with any aluminum components including blocks, heads, radiators etc. If you don't want to change the coolant every 2 years you can monitor the pH or buy brand-specific pH paper and watch the color as it approaches the acidic range over time. By the way, zinc is commonly used as a sacrificial anode in ferrous metal systems, however aluminum is only slightly more reactive (electronegative) than zinc
Thanks for that. I'm gathering they won't do much good but with boats they were essential, why the difference?
It has been probably 35 years since I heard on an anti-freeze that wasn't aluminum-safe. Some may be better than others. If so I don't know which ones. But, I don't know of any that aren't safe to use. Not sure about the anodes. For what it's worth; I have been done projects with quite a few different large truck/industrial/stationary engines. In contact with the coolant those engines typically have both iron and aluminum parts, and some brass an other metals as well. They often have coolant filters, and those filters often have a slug of time release corrosion inhibitor/anti-cavitation additive. In other cases an additive is periodically added separately. But for whatever reason, I have never seen one of those engines with anodes.
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