Engine compartment corrosion protection?

[steve]

I just got a 2003 Jetta TDI, so I'm catching up on 20 years of improvements over my old 84 Quantum TD, and MAN this new stuff is AWESOME!!!

So I read the entire owners manual and it said that if you wash the engine that you will remove the corrosion protection that is on there. What's it talking about? I've never heard of that.

What do you use to put it back on? I don't see anything on the shelf that advertises itself as an engine compartment treatment or whatever. So I'm not sure what to do... maybe it's that stuff that dealers put on the engine to make it look shiny and new. But I don't know what that is either. All the “Armor All” type of stuff say it’s good for rubber & plastic but don’t mention metal. Maybe a good dousing of BreakFree CLP will do it.
http://www.break-free.com/ http://www.madogre.com/Interviews/breakfree.htm

Is there anything I should be concerned about if I just take it the carwash and blast the engine compartment?

[adam_c]

I'm not certain about that specific car, but it's probably chemicals that they put on the battery posts and other electrical terminals throughout the engine compartment.  Things like Di-Electric grease, which is a neutral (does not conduct electricity) compound that blocks oxygen and lubricates fittings without surface bulk.

There could also be chemicals on and around the battery tray that keep corrosion off nearby metal.  If you live on the coast or places that salt the roads, I probably wouldn't wash the engine because corrosion protection could mean rust protection of sheet metal and undercarriage components.

If you live in a rust-free area, then it's probably ok, as long as you don't spray out electrical fittings.  I would probably just wipe down the areas rather than spray to minimize water contacting the electrical system.