Aluminum or Magnesium?

Can anyome tell me if the silver parts under the hood (Intake manifold, Valve head covers, ect.) on my 2003 5VZ-FE are Aluminum or Magnesium? They have developed a whitish powdery oxide to them that seems to come off with slight rubbing from my finger. I have seen that Diluted Vinegar can be used on aluminum parts but not magnesium. Does anyone know for sure. All parts are Aluminum? no Magnesium parts?

 

Cast Aluminum. I've never heard of a single piece of magnesium on these trucks.

 

Thanks I wanted to be sure.

 

I was gonna say, if it was magnesium, wouldn't it react with water?

 

Old mag wheels used to be Magnesium and look very similar to aluminum. Vinegar on magnesium makes flammable gas Nitrogen.

 

Oh shit, I need to go back to high school chemistry. I had it mixed up with Sodium. That's the metal that explodes in water.

 

And the award for risky parenting goes to:

 

You can burn mag, too.

At the bike shop I used to manage, we used to take old rock shox (the good 'ol mag21's) suspension forks and scrape chunks off and burn them with a map gas torch. Probably not the best idea with all the oils and other stuff in the shop...

 

Yep, almost burned down a garage that way.

 

Nitrogen is not flammable. Its an inert gas that take a lot to get it to react with something. Your are breathing about 80% nitrogen right now.

 

He got it mixed up with hydrogen. Vinegar and magnesium produce hydrogen, which is very flammable.

 

its soap residue most likely, car dealers spray crap under hoods to make the engine bay look "pretty" and when it dries up everything aluminum under there looks corroded but the car wash soap does this too if its not rinsed off well.

hose it all down good to wash off "anything" leftover and let it dry, then get a can of wd40 and spray all the aluminum parts very liberally real good and close the hood. its best to let it soak in for a few hours before driving. a few days later it looks great and no more white stuff anywhere.

 

It's aluminum oxide. Aluminum when exposed to the air corrodes and protects itself with a whitish layer of oxides which stops further corrosion. Road salt will continue the process of corrosion. Look at aluminum skinned enclosed trailers that have been used in winter and exposed to road salt.

When welding aluminum this is the same layer you have to remove to weld successfully. Aluminum melts at 660 deg Celsius. Aluminum oxide melts at 2072 deg Celsius. A journeyman I apprenticed under would say aluminum will form oxides immediately after cleaning and would re clean anything if not welded within minutes of cleaning. That is why aluminum is so tricky to weld. If there are still oxides by the time you have enough heat to melt the oxides you have already burnt through the base aluminum and you go from not melting to a hole instantly.

More information than you needed but I hope this explains what you have.

 

Thanks for the replies. And the correction about hydrogen. The engine runs fine, 105K miles. but all the aluminum parts look a little crusty. I think I will try cleaning with diluted vinegar, let dry then some Water Displacement Formula 40. Thats WD40 in case you didnt know. HaHa! This is what they look like prior to cleaning.

 

That is completely normal over time. The only way to avoid it is if the parts are clear coated after manufacturing. You see this sometimes on motorcycles and works well until the coating gets scratched.

 

A mild acid like vinegar may accomplish something, however my experience has been that to really clean it up requires brass wire brushes of various configurations and sizes, and copious amounts of elbow-grease...

 

You can always paint them with Aluma-Blast

 

That looks pretty Sweet There Itchyfeet