IIRC, the WD-40 also helps keep future grease / grime from re-adhering from the undercarriage and helps to keep it clean a bit longer afterward.

 

I'm baffled how WD40 could work. That is..intriguing.

Regarding that "every major area should have a steam cleaner place" (OK not exactly a quote) I've tried to find something like that here in South Florida, with no success. Doesn't mean it doesn't exist, but I've had no luck. They're doing a crappy job of advertising themselves, if they're here!

 

...which would be odd, given how /enviro/ conscious the Bay Area is...they create a really messy runoff...they work TOO well.

 

Lots of simple green, elbow grease and some 90-45 deg. attachments for your pressure washer.

 

I used to think WD40 attracted dirt and grime. Looking at the engine compartment at some of the zinc plated items I used WD40 on to clean up, I don't see much dirt on them, which disproves the theory it attracts dirt.

 

I'm a fan of WD40, but I think mostly for the lovely scent, which it seems I grew up with. I use it here and there, and agree with you Andy about the dirt-attracting theory.

 

As mentioned, a pressure washer shooting a mixture of Simple Green/hot water will be your best bet.

Place a plastic tarp under the car to prevent runoff into the storm drain system.

 

I can borrow the in-law's pressure washer. I just need to get the car higher and get some 45 and 90 attachments.

 

250 PSI means over 400º steam temp, something that's way pas what a home user might consider playing with.

I was thinking that 35 PSI water supply pressure from the house, no check valve, and see no more than about 300º, and certainly less as soon as it starts flowing cold water into the tank. It would be hot water to the nozzle, flash to steam in the way to the car. Mostly a serious hot water wash with some steam.



Disclaimer: Don't try this at home, completely untrained 'professionals' working far enough away from you to make it a non-dangerous freak event rather than an awesome spectacle.

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I put a mixing valve setup in my new garage, so I can rip 160º hot water at will, maybe through a small pressure washer. Haven't even tried it yet.

 

I know that Simple Green is touted as a great cleaner and I have to disagree unless you are using this version




If you are using the crap you get at Home Depot, be sure to wash it off immediately as it will etch a lot of the softer aluminum we have on our cars. I prefer to use Formula 88 which looks like this.




Best stuff that I've used over the counter when you are not using a real steam cleaner.

 

My local H-D doesn't carry the black-bottle stuff.

 

Simple Green (purple HD at Home Depot) works great for first round, then I use Mineral Spirits as it won't harm the painted stuff. Break Cleaner on the really tuff metal parts.

Never tried steam, however there are some detail shops that will do your under carriage on a lift too.

 

Steel bristle brushes seemed to have worked really well so far on my control arms followed by a spritz of Simple Green, and lastly WD-40. I'm going to update my steering rack thread to show those results.

 

WD-40 is a light oil carried by a solvent. It makes an OK 'cleaner' because of the solvent part, but only because it comes in the spray can. There are better solvents-in-a-spray-can, and even better solvents without the spray can. You can do as well using solvents in a spray bottle, provided the spray bottle will stand up to the solvents. Andy, I think you can find a gallon of industrial paint thinner at H-D stores, intended to cut some particular paints. Cali has very particular rules about using it, to the point where the label tells you specifically that it is only to be used to thin those paints, and not to use it for anything else like cleaning/degreasing. Go grab some and a six-pack of industrial spray bottles and go to town. Wear protective gear like a respirator for organic compounds, serious rubber gloves, and chemical goggles. It's way cheaper and much more effective than WD-40 or even brake-clean. It's a little more persistent (higher boiling point) than consumer brake-clean, leaves no oily film as WD-40 does. The fumes and overspray are very unhealthy, extremely flammable, etc, so only use it outside away from structures and ignition sources too.

Or the odorlesss paint thinner in a bucket with a stiff-bristle parts cleaning brush.

 

I can't do the paint thinner cleaning with a child in the home that follows my wife into the garage and wherever she goes. I will stick to Simple Green and elbow grease.