[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