The clean engine compartment allows for easier repair and maintenance work. If you haven't cleaned it in a long time, it may take a while for the degreaser to penetrate through the grime and you will definitely need to use a lot of "elbow grease" to get rid of the grease build-up. It is best to clean the engine compartment before washing the car to make sure you remove any degreaser that could otherwise come into contact with painted parts. By doing this regularly, you can prevent rust from forming; dirt accumulated from the streets and salt are the main causes of oxidation of the metal, so rinsing the engine allows you to extend its life.
Steps
Method 1 of 3: Protect and Prepare the Dirty Engine
Step 1. Eliminate any residue left in the engine compartment
Before cleaning the area under the hood, remove all leaves, blades of grass, twigs and any other foreign objects. If left in contact with the engine or electrical system for long enough, these elements can become a problem and even start a fire.
- Pine needles and leaves usually accumulate along the lower edge of the windshield and then fall into the engine compartment.
- Look for small animal nests, especially when the weather starts to get cold.
Step 2. Disconnect the battery
Spraying water directly under the hood can cause an electric arc, blow fuses, or cause other damage; to prevent this from happening, loosen the nut holding the negative battery terminal and disconnect the ground wire.
- You can choose to disconnect the positive pole as well and disassemble the battery to clean it outside the compartment.
- If you have decided to leave it in its housing, fit the cables sideways to prevent them from coming into contact with the terminal.
Step 3. Cover exposed cables or electronic devices
Although the components under the hood are quite water resistant, it is safer to wrap some electrical elements in plastic foil. Protect the spark plug connectors and disconnect the wires and distributor cap, if present.
- Small plastic bags or cling film offer good water protection.
- If you are not sure if the car is equipped with a distributor or you do not know where the spark plugs are located, consult the vehicle maintenance manual.
Step 4. Leave the engine running for five minutes
It is easier to remove slightly heated fat. Start the car and let the engine idle for about five minutes so that it reaches normal operating temperature and the caked dirt loosens up a bit.
Do not leave the machine on for too long, otherwise you could burn yourself during cleaning
Method 2 of 3: Degrease the Engine
Step 1. Apply an engine degreaser
There are several brands to choose from, but most products act similarly. Spray the degreaser on the engine from top to bottom to make sure you reach the entire surface.
- Most of these cleaners are sold in spray cans, so application to the engine is quite simple.
- Read the instructions on the package of the degreaser you bought, to know the most correct method.
Step 2. Avoid spreading the product on painted components
The engine degreaser is able to remove the clear coat, so be careful not to spray too much while treating the engine; if any splashes reach the fender or other areas of the body, rinse immediately to avoid damage.
- This cleaner is able to make car paint opaque;
- Rinse painted surfaces it came into contact with as quickly as possible.
Step 3. Let it soak into the dirt layer for 3-5 minutes
This product works by literally "eating" the encrusted grease on the engine. If the latter is not excessively dirty, a shutter speed of three minutes is sufficient; if it is very dirty, let the degreaser work for five minutes before rinsing.
- If the instructions on the package indicate different times, respect them;
- The more time the degreaser acts, the better the final result will be;
- After about five minutes, the degreaser should start pouring from the engine.
Step 4. Use a stiff bristle brush to scrub away stubborn grease
As the cleaner penetrates the dirt layer, use a stiff bristle or steel brush to mechanically remove large deposits of dirt, burnt oil and other residues; you shouldn't have much difficulty when the degreaser is already working.
- Wear protective goggles during this phase, so as not to risk the detergent splashing into your eyes;
- Also wear gloves, to avoid prolonged skin contact with the degreaser;
- You only have to scrub the engine if there are large chunks of caked dirt.
Step 5. Rinse the engine with the garden hose
Do not use a high-pressure gun, as it could disconnect the wiring or cause water to penetrate under the plastic covers you covered the electronics with. A normal garden hose with the sprayer set at normal flow is enough to get rid of most of the grease.
If the engine still looks dirty after rinsing, reapply the degreaser and let it work for a few minutes
Step 6. Wash the car
After rinsing the engine compartment, you can immediately start washing the car. This way, you are sure to get rid of any degreaser that may have accidentally spilled onto the bodywork before it can cause any major damage.
- Remember to use a bucket, rags, cloths and different sponges to clean the body;
- Apply the wax to any part that has come into contact with the engine degreaser.
Method 3 of 3: Clean Specific Engine Components
Step 1. Use a metal brush to clean the battery terminals
These items are often prone to corrosion, a problem that causes electrical system malfunctions. Disconnect the cables from the battery and use a wire brush to clean the battery terminals until bare metal is visible.
Dip the battery wire terminals in an anti-corrosion chemical to ensure a strong electrical connection
Step 2. Apply baking soda and water to the battery acid
If the corrosion is caused by a leaking acid, you can neutralize it with water and baking soda while cleaning the battery. Pour some baking soda into the bucket of water and mix the ingredients thoroughly; dip the brush into the solution and use it to scrub the terminals and other areas affected by the acid.
Baking soda is a perfect cleaning product, as well as effective in neutralizing battery acid
Step 3. Use a stiff bristle brush and sponge on the plastic parts
Plastic-made components under the hood, such as engine casings and fuel caps, are difficult to clean by brushing them. Start by working with a stiff, plastic bristle brush in combination with soap or degreaser and, once stubborn encrustations have been removed, switch to a soapy sponge to get rid of the last residue; when finished, rinse with water.
- You can also decide to disassemble the components to clean them outside the engine compartment, but this is not strictly necessary.
- Do not use steel brushes on the plastic pieces, as you may scratch them.
Step 4. Use a spray brake cleaner to remove localized grease deposits
Insert the straw into the nozzle of the can and direct it to the points or areas where the layer of dirt is particularly thick. Use a stiff bristled brush to scrub the grease off and then spray on more brake cleaner to rinse the area.
- Be careful when using this product indoors, as its vapors are dangerous.
- Brake cleaner spray is highly flammable, so do not use it while smoking or near open flames.
