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How to Polish the Fins on an Aluminum Engine

by Mary Lougee

Aluminum is a lightweight metal that weighs about a third of the weight of steel. Aluminum engines are corrosion resistant with light reflectivity that gives them a bright shine. Engines get dirty from road film, leaking fluids and road salt. Properly cleaning and polishing aluminum engine fins enables a mirror-like finish for a show-quality car or motorcycle.

Step 1

Let the aluminum engine cool completely.

Step 2

Place a nozzle on a garden hose and turn it on. Spray the aluminum engine fins thoroughly with a strong stream of water. This will loosen and remove any surface film.

Step 3

Squirt car shampoo into a bucket and fill with water from the garden hose to make a soapy mixture.

Step 4

Dip a sponge into the shampoo mixture and thoroughly scrub the engine. Press the sponge into the sides of each fin to reach deeply inside and clean it.

Step 5

Spray the engine off with a strong force from the garden hose.

Step 6

Let the engine dry.

Step 7

Place a small polishing wheel into the chuck of a drill.

Step 8

Squirt aluminum polish onto the tip of the cone-shaped wheel.

Step 9

Turn the drill to the "On" position and insert the tip of the wheel into the side of each fin to reach the deepest area of the engine. Pass the drill back and forth along the fin side of each fin. Add extra polish to the tip as necessary to polish the entire engine.

Step 10

Rinse the engine to remove any excess polish with the garden hose under full force.

Fold a chamois in half and hold each end in a hand to make it taught. Press the chamois into the channel on one side of a fin and pass it back and forth to dry it. Continue this process on each side of each fin and over the entire engine to dry it. Wring out the chamois when it no longer absorbs water from the engine.


  • Aluminum engine fins must be clean prior to polishing them so the polishing wheel does not rub sediment or dirt in the fins.
  • Drying an aluminum engine with a chamois will remove any water spots that will mar the shine.


  • Rinse the car shampoo and polish thoroughly from the engine. Leaving any of the substances behind will cause a dull cloudy finish on the aluminum and can discolor the hoses.

Items you will need

  • Garden hose with nozzle
  • Bucket
  • Sponge
  • Car shampoo
  • Aluminum polish
  • Small polishing wheel-cone shaped
  • Drill
  • Chamois

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