[Elderado82]

There is nothing wrong with using a power washer on your engine bay. Just be mindful of a few things:

1. Electrical wires and wiring harnesses, batteries, alternator, and fuses.

2. Don't flood the area of the engine where the spark plugs and ignition coils are. These should be sealed, and water shouldn't be able to get down into the cylinder head, but if it does, this can cause massive issues.

3. If you have a cone intake filter or open cold air intake, make sure to seal it off from the water.

Other than that, spray down the engine bay with a good degreaser, let it sit for about 10 to 15 minutes, and lightly brush any problem areas with a bristle brush, then rinse. I would personally shy away from using high pressure but instead use low pressure and focus on up-close, detailed cleaning.

You may get wet and experience splashback, so make sure to wear eye protection to prevent the degreaser from splashing into your eyes. The main thing is to be mindful of where you are spraying the water, and if you do get water in those areas, try to use compressed air to dry them out.

Also, it's a good idea to take the car for a nice long drive afterward to burn off any moisture that may be sitting. Water is corrosive and will accelerate corrosion and rust.

[Elderado82]

Originally Posted by 21X3M40

Question regarding the under-shield or under tray. On my 22 X5 a very large portion of the car is covered underneath, would it be prudent to remove the cover(s) before doing an engine detail/wash so the residue does not collect in the under tray(s)?

I know this would mean extra time and work to remove the undertray(s) before doing an engine wash. I am open to suggestions. TIA

No, these are made to properly drain. There are drain holes, and the tray is designed for water to drain out in the direction of the drain holes. You'll be fine. Just take the car for a drive, and it'll air out.

[NYG]

The only things you should know is:

Don't pressure wash connectors and wait till the engine is COLD before you spray cold water on it.

[bosstones]

You can use a 0° tip to really get into those hard to reach nooks and crevices.

(please don't actually try that)

[tracer bullet]

I think after reading all this again the answer is: If you're in doubt, don't do it.

The summary is that it's totally safe, as long as you don't do this, or this, or this, or this and be sure to also do this and this and this as well.

I'm well aware that these are all things that can be done, and it'll be OK, but the average person doesn't understand 2/3 of what all the things are that need to be done. I know where my engine takes in air, I know where my plugs and coils are because I've changed them, but the average person has NO idea what these things mean.

If you have to ask this question, the answer for you is probably going to be no, don't do it.

[Yuille36]

I would be reluctant to use a high-pressure washer, the problem is that water can be pushed up into connector causing electrical gremlins. Instead, I use your average garden sprayer that you pump up to create pressure. That and some degreaser or engine detailer would be fine, along with a brush to agitate the area. And some microfibers to wipe every down. But people will do what they think is best.

[suitedcboy]

I know cars get pressure washed engines but the issues that it can cause happen much later. The rubber seals that get crimped on the wires where they enter the connector housings are not stout enough to stop water with mu ch force from blowing past. The safe and effective way is to initial rinse and finale rinse with a garden sprayer filled with water and pumped up like your applying bug spray. Wash away the dirt and dust and then spray on degreaser or engine cleaner spray. Wait a couple of minutes ad use the garden sprayer to rinse it off. If still oily or dirty in spots, use a paint brush with degreaser or cleaner and brush around the worst spots and rinse again. If you use a garden hose with a sprayer that has the selectable spray patterns, the rain sprinkle spray is safe. If you wouldn't an open cut hit the spray jet then it isn't for wiring connectors. The other area to avoid is coils. The plug boots are not meant to be water deluge sealed.
In recent years of repairing vehicles I have replaced a lot of engine bay components where water got into wiring connectors and corroded terminals on components that were costly to replace. Many were used crs tht had been detailed and they had owned the vehicle 18 months or more and never cleaned engine but it had clear evidence of an engine bay cleaning.

[d.arcibsango]

This has always been a fear of mine also

[stbm5]

i was watching a larry kosilla/ammo nyc video the other night and he pretty aggressively uses a power washer in engine bays, often less than a foot away.

[FSHNGRY]

Originally Posted by carseatsm5

I think I can as long as I’m careful around the air intake. But can I really?

Would like to clean the engine compartment but am skeptical I won’t ruin something.

I hold my washer from like 4 feet away and barely mist it, than use a brush and a chemical guys product to meticulously go through spots that need a cleaning.

After that - a micro fiber w G Technique "all purpose cleaner to wipe it down

the whole point is to just "mist" it

[Yuille36]

If anyone is reluctant to spray down their engine using a pressure washer, I would suggest buying a garden sprayer that you physically pump to create pressure.
This works like a dream, you can turn the nozzle to just mist the engine, agitate the dirt and spray again then wipe down.

https://www.amazon.com/Chapin-Intern...%2C338&sr=8-15

[FSHNGRY]

Originally Posted by Yuille36

If anyone is reluctant to spray down their engine using a pressure washer, I would suggest buying a garden sprayer that you physically pump to create pressure.
This works like a dream, you can turn the nozzle to just mist the engine, agitate the dirt and spray again then wipe down.

https://www.amazon.com/Chapin-Intern...%2C338&sr=8-15

another great tool and method - great thinking

[Yuille36]

Originally Posted by FSHNGRY

another great tool and method - great thinking

This is what I use for both my engine and my wheels.

[Bullydad]

I had to read through this thread just for the entertainment of some of the things people are saying that makes no sense. Unless your car is old there's nothing to worry about. Just don't spray directly in the air intake. Even if somehow a little water got in there you're going to be fine. Every electrical plug is sealed so good that they make them hard to unplug by hand. Saying you can't pressure wash the engine bay on a car is like saying you can't wash a motorcycle and if that's the case I been doing it wrong for a long time without anything happening. Good luck with hand cleaning with a paint brush.

[jwmFcreek]

I would screw up the engine water blasting it others may not I would I am sure after that I would have to pressure wash the interior .

[nazali]

I have, I wouldn't, if I where you I wouldnt, if something breaks it'll be expensive.

Car engines are not water proof, nor are they meant to be, the best analogy is watches,
you get watches which are "splash proof,water proof and PREASURE resistant"

Dont take your expensive splashproof timex diving

An engine bay is designed to get WET, from below, not preassure washed.
Unless you've got an OIL bomb in your car there is no need.

An OILY engine bay acts as a detterant from rust.

Besides NO-ONE EVER saw a BMW driving past and said, "man I bet that engine bay is pristine"

And I've run clubs where we stand around looking at our cars about 15% of the time somone will pop the hood...

Other than the mechanic, who you trying to impress ?

[MaineSport]

Watch a YouTube video on how professional detailers do it. I'm not seeing a lot of high pressure water but mostly hand pump sprayers to loosen up dirt and grime. I'd hate to be chasing gremlins because of shooting water where it shouldn't be.

[Randy Johnson]

Originally Posted by TR930

Not unless you want to Brick your DME.

Not true. Just don’t use a too high pressure setting. Watch car detailing on YouTube. They do it all the time. Anyone that says otherwise is doing it wrong.

[argb]

Originally Posted by Yuille36

If anyone is reluctant to spray down their engine using a pressure washer, I would suggest buying a garden sprayer that you physically pump to create pressure.
This works like a dream, you can turn the nozzle to just mist the engine, agitate the dirt and spray again then wipe down.

https://www.amazon.com/Chapin-Intern...%2C338&sr=8-15

great tool, makes things much more controllable

[argb]

there are several videos on yt suggesting the use of tyre foam for cleaning the engine. Has anybody tried it?

[bosstones]

Originally Posted by nazali

Besides NO-ONE EVER saw a BMW driving past and said, "man I bet that engine bay is pristine"

I know that I've wondered if my N55 is less oily than other N55's I've seen on the road or in the work parking lot.

[John in VA]

Originally Posted by argb

there are several videos on yt suggesting the use of tyre foam for cleaning the engine. Has anybody tried it?

Tire foam is not a cleaner. Are you trying to clean, or shine the black plastic parts?