This simple guide will show you how to safely detail your dirty engine bay without any fear of hydrolocking your motor or shorting any electrical systems. This is the same method I use on professional jobs and also to clean my own cars.

Protecting Parts & Exposed Wires

It’s important to prevent moisture from getting to the alternator, distributor cap, and any exposed electrical wires so tape these parts up.

Disconnect your battery and cover both terminals with tape or remove it altogether by disconnecting the terminals and battery tie-down strut.

Stuff a towel in the air intake inlet (or cover it with a plastic bag or Ziploc bag if you have a cone filter).


Liberally spray a degreaser like Meguiar’s Super Degreaser on all surfaces of the engine bay. You can also spray the underside of your hood if you want to clean the hood too.

Let the degreaser sit for at least 30 seconds and make sure it doesn’t dry.

Next, use a steam cleaner and brush to agitate all parts of your engine bay. Avoid getting moisture in the air intake inlet. Start from the top (bottom side of hood) and work your way down. If the degreaser dries, then apply more degreaser. Afterwards, use clean dry towels to wipe down the surfaces you’ve agitated.

If you don’t have a steam machine, then a pressure washer or a regular garden hose can work too, although you’ll have to use a bit more caution. Avoid spraying water on: the air intake inlet, the alternator, the distributor cap, and any exposed electrical wires.


Wipe away any excess water that might remain with clean and dry microfiber towels.

Pro-Tip: Use compressed air to get to those hard-to-reach spots.

Remove and discard the tape used to protect the battery, distributor cap, alternator, and exposed wires.

Wipe or blow away any excess moisture.

If you removed the battery earlier, then put the battery back in the battery tray and secure it with the battery tie-down strut.

Let the engine bay air dry.

Overall, this entire process should take about an hour, depending on how dirty the engine bay is. You’ll need more towels for excessively dirty engine bays.

If you know anyone who wants to clean their engine bay, then please pay it forward by sharing this page with them. Thank you!

Categories: Exterior