How to Clean a Car Engine

As you drive, your engine accumulates grime and dirt from miles on the road. Old fluids or small leaks can also make it look messy under the hood.

How to Clean a Car Engine

Your engine needs an occasional cleaning to get it looking new again. If you're getting ready to sell your car, want to make it easier to spot leaks, or just want to give it a good polish, cleaning your engine is a smart thing to do.

Part 1: Find a location

Dumping dirty, contaminated water into city streets or sewers is illegal, so you need to find somewhere with proper disposal facilities to wash your engine. Some self-serve car washes have an area for cleaning engines, so this could be a good place to start.

Part 2: Gather cleaning materials

Get all your cleaning materials ready for the job ahead. You will need:

  • Large bucket
  • Degreaser solution
  • Scrubbing brush
  • Wet/dry shop vacuum
  • Water hose or pressure washer
  • Waterproof gloves
  • Safety glasses
  • Plastic bags

Part 3: Cleaning the engine

  1. 1. Use plastic bags to cover delicate components. Open the hood and cover sensitive electronics like fuse and relay boxes, computer units, and the alternator with plastic bags. Also cover the air intake.
  2. Mix the degreaser solution with water in the bucket. Follow the directions on the label to determine proportions.
  3. Scrub the engine. Use the brush to give all parts of the engine a good scrub with the degreaser solution.
  4. Let the degreaser solution sit on the engine. Letting it sit for 15-30 minutes will let it break down any caked on grime.
  5. Rinse the engine. Use your hose or pressure washer to spray off the degreaser solution. Be careful not to use too strong of a spray setting: it's important to avoid forcing water into bearings, electronics, or other sensitive areas.
  6. Dry the engine. You can let it drip dry, or use your vacuum to suck up any remaining water. Turning the engine on will heat it up, causing water to evaporate.
  7. Repeat as necessary. If you still see dirty areas after the rinse, follow steps 3-6 above to get them clean.

Make sure to remove the plastic bags you applied earlier before you close the hood and finish the job.