Do you guys pressure spray your engine bay? How do you all clean your engine bays?

I used my home pressure washer to clean my engine once. The next day the passenger side heater was permanently stuck in the FULL ON position. It was 114F that day and I couldn't turn on the A/C because the heat coming from the passenger side overpowered the cold air coming from the A/C, even when the passenger side vents were closed.<br>
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I'll never know for sure, but I think I got water into the electronics of the heater control valve. The dealer covered it under warranty, but I didn't offer the info about pressure washing the engine. I definitely won't be pressure washing the engine any more, though.<br>

they warn about protecting all the electrical connectors. I generally just soap spray the dirty areas using some of that orange peel stuff, then carefully hose down the area with an open end hose. I go after the rest of the bay with wet rags and brushes, it seems to work OK.

...this is relatively safe if there are no chemicals used, however if the wiring harness is old the steam can shread the insulation. Most electronics are pretty well sealed, although usually you have to open and dry out the distributor and sometimes the plug wires at the caps. <br>
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San Jose Steam Clean does a pretty good job.<br>
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Note that the only times I've steam cleaned are right before pulling out an engine or transmission (less of a mess) and one time an engine oil seal blew and coated the engine compartment in oil. I wouldn't recommend it on a regular basis. Some Gunk or similar engine cleaner spray and a light garden hose watering can also do the trick.

We had to steam clean my dad's 1972 450SEL engine because my Mom had left the oil cap open. THere was oil everywhere. Luckily the engine didnt cease. However, after they steam cleaned the engine, a few hoses had become warped (since they were pretty old) and those burst.<br>
Only do it if:<br>
A. you have oil all over the place<br>
B. you are entering it in the concourse, but make sure all the cables and hoses are new<br>

But with all the very low voltage electronics on board now a tiny bit of water in the wrong place and you can fry something important. Steam has a tendency to get into places that water can't reach. I don't think I'd go that route anymore.