Aussie66Fastback

anyone know what causes the corrosion in alum radiators or how to slow it down????

I was head down under the hood last night and i could hear this hissing sound like coke in a can. car is dead cold. hasnt been started for a couple of weeks. I pulled the radiator cap and inside is bubbling. massive corrosion problem. pulled the filter. its clogged too. I've never seen anything like this before.

its running water with water wetter. i thought that stuff was supposed to have anti-corrosives in it for alum rads and heads????

Randys66gt

You have to run antifreeze also!!!! without it, it does cause electrolysis which is what you are getting. Water wetter is great if it is used with antifreeze. Good luck

Aussie66Fastback

i may have had some bad advice
i got told for race application to only use water with water wetter, no antifreeze. frankly that never would have occured to me cos it never freezes here anyway.

i'm trying to get some pics up on pbucket.

Aussie66Fastback

Randys66gt

True, it doesn't freeze here either but the lubricant in the antifreeze stops the problems. Hope it hasn't totally destroyed anything. Good luck.

Starfury

Yeah...but only so much. Not nearly enough to account for an aluminum radiator with a cast iron block. You need to be running coolant as well. 60/40 water/coolant with water wetter is a pretty good mix.

In your case, corrosion is due to the two dissimilar metals in the system, aluminum and cast iron. The aluminum has a stronger tendancy to oxidize than iron, so it becomes an anode in the system, meaning that aluminum atoms have a tendancy to oxidize and break free, transferring electrons in the process to the cast iron in the block.

Most decent green coolants (ie. Prestone) have a fair amount of corrosion resistant additives which act as sacrificial anodes in a cooling system. Probably not enough for a cast iron/aluminum system as big as yours, but some. The water wetter should provide a bit more. Even so, you should change your coolant at least once every two years, if not more often.

You may consider using a cap with a sacrificial anode built in. Many Mustang wherehouses (and I think Summit) offer a cap with a copper slug connected to the bottom of the cap. The copper acts as a sacrificial anode to preserve the aluminum in the system. When most of the copper is gone, you replace the cap.

Starfury

After reading a couple of the replies posted while I was typing...the reason you're supposed to run pure water during a race is because most tracks require it. Coolant isn't easy to clean off a track, water is. A little water wetter diluted in water isn't going to be noticable, but will help cool things down.

For the street, you should always run some form of coolant.

I also forgot to mention, STAY AWAY FROM DEX-COOL!. Dex-cool was GM's "solution" to aluminum corrosion...and it failed. They're just now realizing this and switching away from it.

fakesnakes

I was reading this thread, going, yep, yep, yep, Tad's on top of it as usual, no need to reply.

Then I got to the Dex-cool comment. I didn't know that and have two gallons sitting in my garage waiting to go into my car! Not any more...

Starfury

The idea behind dex-cool was that it was supposed to be a long-life (75k+ mi) coolant that would prevent corrosion in GM's new aluminum engines. Turns out that it doesn't work. It doesn't have nearly the corrosion resistance properties they thought it did, so now all these cars that have it are rusted out internally.

If you change your coolant as often as you should (at least every 2 years), you'll probably be fine. That said, I'd switch away from dex-cool in a car I owned just to be safe.

Aussie66Fastback

thanks Tad

i flushed the whole system about 20 times until 2am!!! I couldnt start the car cos its too loud but that's the beauty of an electric water pump to circulate things. refilled it with clean rain water and I still couldnt stop it from fizzing.

I get why its corroding now, its just the rate that scares me.

I added some new ethylene glycol based coolant with corrosion inhibitors and claiming to protect all metals yada yada.

I pull the cap next morning, its like a champagne cork its still fizzing!!! building pressure even without warming up.

last night i pulled the radiator and will send that back to the manufacturer. its badly blocked with that crud.

i know there is going to be a pissing contest between the engine builder, the radiator manufacturer, the parts supplier. They're already arguing over which coolant is best/worst and conspiracy theories on how all coolants are made to fail so there is ongoing sales of replacement parts and how rad manufacturers use acids in the welding process and if its not flushed it will eat your engine...f**king blame game.