Rick's Free Auto Repair Advice

How to clean your engine bay

Steps to safely clean your engine bay

Don’t even think about using a pressure washer to clean your engine bay or remove grease from your engine. A pressure washer will force water into electrical connectors causing a no start condition when you’re done. Here’s the safe way to remove grease and clean your engine bay safely.

Start by protecting the electronics

Buy a few boxes of static cling and Press’n Seal wrap from a discount store. Wrap all electrical connectors in the engine compartment with either the cling or Press’n seal wrap. Drape Press’n seal wrap over the alternator to seal off all the openings. Or, slip a plastic bag over the alternator and seal in place with masking tape. If your engine has a vanity cover, remove it and place it aside. Then remove the ignition coils and wrap them together to protect them from the degreaser and water.
Spread the cling or press’n seal wrap over the valve cover and spark plug area to keep water out.

stretch wrap for engine degreasing

Engine cleaning tips and myths

If your engine has coil on plug ignition, exert extra care to ensure water doesn’t enter the spark plug tubes. In fact, it’s best to use a spray bottle cleaner like Krud Kutter (instead of GUNK aerosol engine cleaner) on the valve covers. Hand wipe the valves covers with a rag or paper towels and avoid soaking with water afterwards.

Avoid Pressure washers

They make a quick job of engine bay cleaning. But they can also do a lot of damage. The silicon seals in electrical connectors weren’t designed to withstand 3,000 psi. so they leak and short out the electrical contacts. Worse yet, pressure washing not only forces water into the connectors, but also the cleaning agents and grease and oil. That can cause corrosion down the road. It’s plenty tempting to use a pressure washers, but I urge you to avoid it. They’re nothing but trouble.

Biodegradable engine cleaners still pollute

You’re kidding yourself if you think using a biodegradable water based cleaner doesn’t pollute when doing an engine bay cleaning. All that oil and grease that comes off your engine is considered a pollutant. Just because the soap biodegrades doesn’t mean the oil will as well. If you use a biodegradable soap but let the runoff flow into a sewer, YOU’RE STILL POLLUTING!. You must use an absorbent pad to collect the oil and grease runoff.

Degrease and capture

Purchase a foaming or gel spray degreaser like GUNK Foamy Engine Cleaner, GUNK Heavy Duty GEL Engine Degreaser or GUNK Original Engine Degreaser. Next, purchase an absorbent mat from a local auto parts store or from newpig.com. Place the mat under the engine bay so it captures the greasy runoff. Why is this so important? Because all the runoff from your engine bay cleaning project can pollute the drain water.

gunk engine degreaser products

That grease on your engine is formed from actually motor oil that’s been baked on from heat. When you dissolve it with an engine cleaning product, it’s considered a pollutant. If you simply rinse off your engine and allow the runoff to flow into the storm sewer or into your grass, you’re polluting. How much? Get this; a single quart of motor oil residue pollutes 250,000 gallons of clean water and that polluted water will make its way into lakes and streams.

An absorbent mat will attract and hold the oily drippings. Then you can dispose of the mats in your garbage instead of letting that oil and grease flow into fresh water suppliers.

Warm the engine and apply the degreaser

Start the engine and run it until it’s warm, but not hot. A warm engine will soften the baked on grease. But a hot engine will quickly evaporate the cleaning solvents in the degreaser. Once warm, spray the degreaser onto the engine, starting at the top. Let the degreaser sit the recommended time. Then brush the biggest accumulations with a wire or nylon bristle brush. Reapply degreaser to those areas so it can penetrate through the brush marks.

Then rinse with a garden hose nozzle. Repeat the degreaser applications for really tough areas.

Finish the job by applying GUNK Engine Protector Spray. The spray adds a protective layer to your engine components that make future cleanups much easier. Plus, the spray adds a nice shine to engine components.

If you have an air compressor, blow off all excess water before removing the protective wraps.

Remove protective wrap

Unwrap all the electrical connectors and reinstall any ignition coils

©, 2019 Rick Muscoplat

Posted on by Rick Muscoplat


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