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Washing engine bay

1187 Views 5 Replies 6 Participants Last post by  4banger
I have a 2011 335i coupe. I want to wash the engine bay. Is it safe to just spray the engine off with a hose, will I damage anything, is there anything I should be careful with? Any advice will be greatly appreciated.
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At the minimum, cover the alternator.
Unnecessary; it is reasonably protected from water intrusion. Just don't soak it with a heavy or high-pressure stream. Both of those comments apply to the engine as a whole.

Everything in the engine bay is generally safe to hose down with a gentle to moderate spray. Never use a pressure washer. Don't try to blast away grime with water; use a decent all-purpose cleaner like P21S, agitate with a sponge or brush and hose off. Leave all trim covers in place and avoid directing the spray underneath them. Blot dry with an old towel whatever you can reach and leave the rest to air-dry.

When you do wash the engine bay, make a habit of doing so before washing the rest of the car. Not only does this keep gunk off your freshly-washed paint, it affords drying time before you start the engine. The ignition coils are about the only components that react very badly to being soaking wet--you'll get heavy misfires until they dry out--but as they are protected by trim panels and water seals, once again you will be fine unless you go crazy with the hose.

Oh, and stay away from Simple Green. It is not friendly to aluminum and there's a lot of aluminum under a BMW's hood.
At the minimum, cover the alternator.
No high pressure. Otherwise I've only had minor issues on my 1991 Tercel, but it lasted just a minute or two. I suspect part of the intake wasn't sealed that well or some moisture got into the distributor.

Never on any of the 7 cars I've own since then. All had direct ignition.

You an operate the car in heavy rain. Some of that water makes it past the radiator. Motorcycles are completely exposed to water without issue. Very little difference in overall construction that I could tell.
Id cover the alternator, thats about it. I light spray of simple green or another cleaning product, light brush and like everyone said a light stream of water. Id also do it when the engine is cold.
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