Motor & Compartment Detailing

by Jeremy Goodspeed

A clean motor and compartment has many advantages. It becomes easier to detect oil or fluid leaks, belt wear, missing or improperly installed caps and air cleaners and of course it looks good. A clean engine will also run cooler and is easier to maintain.Motor Detailing Process

GETTING STARTED: There are a few things that need to be done before plunging into a motor compartment cleaning. First, open the hood, and evaluate the condition of the motor. Look for loose or missing items such as fluid caps etc. Next, vacuum loose leaves from the cowling and vacuum the hood insulator making sure that vacuuming will not damage it. Finally, warm up the motor. Engines clean better when they are warm, not hot. A warm motor allows greases to become softer and easier to remove. Only allow motor to run for a couple minutes or until temperature starts to rise.

PRECAUTIONS: Before de-greasing the motor, use plastic bags to cover the distributor, coil and air intake and filters. Although these areas are water resistant, this is a precaution. Also, check the tightness of all fluid caps and dipsticks. Do not remove the air cleaner.

MOTOR CLEANING: Start by rinsing the fenders, grille and windshield to eliminate any staining of the de-greaser. Also rinse the motor and the compartment to free any loose dirt. The use of an electric pressure washer will assist on heavily soiled vehicles but is not necessary. If a pressure washer is used, do not get to close, as damage could result. Next, apply engine de-greaser to the motor and its compartment and allow to soak for a minute or two (check manufacture directions). Do not allow to dry on any surface. Always use a "surfactant" type water-soluble cleaner. This type of de-greaser is usually labeled as "non-flammable". Agitate with assorted brushes to loosen stubborn pockets of grime. Light levels of dirt/grease may not require agitation with brushes. Rinse and re-inspect. Look for pockets of grease. Use de-greaser on problem spots, allow to dwell and rinse. Accessibility to hot water from a hot water heater source will aid the chemicals effectiveness. Every 20-degree temperature increase doubles the chemicals effectiveness.

When de-greasing a motor, avoid the following areas:


    Hood insulator

    EGR Valve

    Air conditioning compressor

    Air intake (older vehicles)

    Alternator / generator

After the motor compartment is free from dirt, grease and grime, inspect the battery tray and terminals. If the battery or the terminals haven’t been cleaned in a while, use an aerosol caustic neutralizer. This product is simple to use and turns pink where battery acid is present. Allow soaking for one minute, and rinsing thoroughly. A 50/50 mixture of baking soda and water will also do the trick.

The next task is to dry the motor. This is easy to accomplish using compressed air and a blowgun. Put particular attention around electrical connectors and areas where water can collect and stand. Starting the motor will also help, however belts will sling water onto side panels and to the underside of the hood.

MOTOR and COMPARTMENT HAND CLEANING: Now that the motor is free from grease and grime, some hand cleaning will improve the overall condition of the motor. Hoses and vacuum lines often have a white powdery residue (mold release). This is the compound that allows hoses to safely be removed from their molds at the factory. Although this is not harmful to the hoses, it is unsightly. Hand clean hoses with a body solvent to remove residue, and allow air-drying before starting the motor. Next, hand wax painted areas (jambs, painted areas under hood, etc.). Remove battery terminals and clean battery posts if necessary. Inspect for worn items such as hoses, wires, belts, etc.

FINISHING: For the final touches on the motor start by checking all fluids including windshield washer levels, add if necessary. Apply rubber dressing to all hoses and plastic parts to add contrast. An aerosol dressing is the effortless way to accomplish this task. Simply spray and brush in with a 3" soft paintbrush to an even gloss. Dressing hoses will also aid in future cleaning by sealing hoses from dirt penetration. Last but not least, inspect.