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Engine Bay Steam Cleaning: The Safe Way to Clean


Water and electricity are best kept separate. Although modern engines and electrical connectors are more water-resistant than before, dousing them with water is not good. While some water finds its way into the engine bay when driving in the rain or snow, it doesn’t compare to the amount of water coming from a hose.

So, how can you clean under your car’s hood? Vapor steam cleaners are one of the most effective ways to clean the engine bay. It’s also less harmful to components because of the method’s low moisture content of roughly 5%. Still, be careful when cleaning around electrical connections, spark plugs, and the alternator, which can be more susceptible to water damage. Fixing water damage can cost a few hundred dollars for a new alternator or more than a thousand dollars for cylinder head replacement from seized spark plugs.

Steam cleaners have incredible cleaning power, with temperatures upward of 300 degrees Fahrenheit and pressure levels of 75 pounds per square inch (psi). Also, using an all-purpose cleaner helps clean baked-on engine gunk. Presoaking the engine in the cleanser and agitating with various brushes will loosen the contamination and allow the steam to clean surfaces effortlessly. After the engine compartment looks spotless, it’s best to add a plastic, vinyl, and rubber protectant. Applying protectant under the hood makes engine covers and hoses look better and can help extend their lifespans.

Engine Steam Cleaning Explained

Benefits of a Clean Engine

The engine bay is often not included during car detailing and might only receive attention every few years or when it’s time to sell the vehicle. When was the last time you had a peek under the hood of your car, truck, or SUV? Unless you change your engine oil and perform other essential maintenance, the answer is possibly never. Maintaining a clean engine bay has multiple benefits in addition to looking good.

Chevrolet Camaro Engine Bay Steam CleanedEasier Engine Maintenance – A clean engine is always welcome by the mechanics working on your car. It is easier to spot leaks and pinpoint the source when the surface is free of dirt and debris. Discovering leaks early can help prevent more expensive damage farther down the road. Also, dirt holds onto moisture and can cause accelerated corrosion on metal parts because they are constantly damp.

Extended Engine Life – Steam cleaning the engine bay can help extend engine life and reduce the risk of fires. Keeping contamination buildup to a minimum will help reduce rust and prevent plastic, vinyl, and rubber from drying out. Conditions in the engine bay can be pretty extreme, with plenty of heat that can spell disaster for an engine covered in grease, oil, or fuel.

Increased Resale Value – Last but not least is increasing the vehicle resale value. Have you ever sold a car and asked yourself, “Should I have cleaned my car before selling it?” The answer is going to be a strong “YES!” Performing a presale car detail that includes the interior, exterior, and engine compartment will increase the value of a vehicle and help it sell faster. A clean engine gives prospective buyers peace of mind because it can indicate proper car maintenance.

Steam Cleaning vs. Pressure Washing

There is more than one way to clean an engine, and each method has its benefits and drawbacks. Two popular engine cleaning methods are vapor steam cleaning and pressure washing. Steam cleaning is safer than pressure washing but is usually more time-consuming. Also, a commercial-grade steam cleaner isn’t necessarily cheap or something many people can access. A consumer-grade steam cleaner will get the job done to a comparable level, but it will take a lot more time.

Steam Cleaning Chevrolet Camaro Engine

A high-end vapor steam cleaner is the way to go when cleaning dirty and delicate areas of the car. The vapor steamer produces low moisture steam, usually around 5% water, making them a safe option for cleaning delicate engine components. More expensive steam cleaners may have a continuous fill feature. With this functionality, if the boiler runs out of water midway through an engine compartment detail, you don’t need to wait to add more water. Consumer steam cleaners typically must cool down before adding more water to the boiler, or severe burns can occur.

Pressure washing is another way to clean the engine bay, but it has unique risks. While the steam cleaner is more likely to cause injury to the person using it, a pressure washer is more likely to damage the engine. A steam cleaner might use a gallon of water per hour at around 100 psi. For comparison, a pressure washer may use a gallon per minute and over 1,000 psi. Be careful when using a pressure washer because the extra water and higher force can cause issues for specific engine components.

Should I Steam Clean My Engine?

Is your car more than a few months old, or has it been a while since the last engine bay cleaning? If so, steam cleaning the engine should be on the to-do list of vehicle maintenance. Steam cleaners are relatively safe for DIY detailers, and entry-level models cost around $200. If you’re more comfortable having a professional detailer clean your engine, the cost is approximately $75.

Engines will benefit from more frequent cleaning if the car, truck, or SUV is driven off-road in dusty conditions. In addition to cleaning the engine, replacing the air filter to keep the engine operating at peak performance is a good idea.

Engine Steam Cleaning Instructions and Tips

Steam cleaners use boiling water, sometimes more than 300 degrees, so be cautious when operating one. When the steam starts and stops coming out of the nozzle, there will usually be a spurt of scalding water for a second or two. Always point the nozzle away from what you are trying to clean, and be careful that boiling water doesn’t drip on any exposed skin when starting or stopping the flow of steam.

Applying an all-purpose cleaner and agitating with various brushes will help the steam cleaner make short work of even the most stubborn engine grime. After presoaking the engine bay with an all-purpose cleaner and letting it sit for a few minutes, the surfaces are ready for steam cleaning. Occasionally a second application of the cleaner is required, and the heat from the first round of steam cleaning will help increase the cleaning power.

After the engine bay is spotless, applying a plastic, vinyl, and rubber protectant is the final touch. Many products on the market will provide months of protection between applications. However, a ceramic coating is the best choice if you’re looking for a product with more long-term protection.

Engine Steam Cleaning Step-by-Step Instructions:

  1. Open the hood and make sure that the engine isn’t hot.
  2. Remove the plastic engine cover if applicable.
  3. Apply all-purpose cleaner with care to avoid sensitive areas of the engine.
  4. Agitate the cleaner with various brushes and let it sit for a few minutes.
  5. Steam clean the engine bay to begin removing dirt and debris.
  6. Use a microfiber towel to remove the loosened contamination.
  7. Dry the engine bay using microfiber towels and forced air if available.
  8. Apply plastic, vinyl, and rubber protectant or ceramic coating.

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FAQ

Can a car engine get wet?

Yes. Car engines get wet when driven in the rain or snow, especially the lower portions that aren’t protected by the hood or fender liners. The top of the engine is a bit more sensitive to water. Avoid getting water into the alternator, electrical connections, and spark plug wells. Also, don’t let any water pool near the battery terminals to prevent accidental shock.

What to cover when cleaning an engine?

A few engine components are more susceptible to damage than others. They may need to be covered to reduce the risk of accidental water damage. Use plastic bags or plastic wrap to shield the alternator, battery, electrical connections, fuse box, and air intake if the filter is exposed. Don’t forget to cover the distributor along with the other water-sensitive engine components that must be covered when cleaning an older engine.

Can steam cleaning remove engine oil?

Steam cleaning an engine will remove leaking or spilled engine oil. In addition to removing spilled oil, a steam cleaner will clean up any spilled engine coolant, brake fluid, or transmission fluid. The high-temperature steam is well-suited for removing any stubborn contamination that may accumulate under the hood.

Is steam cleaning an engine safe?

Steam cleaning an engine is very safe because it limits the risk of water damage compared to using a hose or pressure washer. When using a vapor steam cleaner, the risk of damage is even lower due to the low-moisture steam with only around 5% water content. A steam cleaner will put less water into the engine bay in an hour than a hose will in one minute.

How much does steam cleaning an engine cost?

The average price to steam clean an engine starts at $75, and the price increases with larger engines or ones with lots of spilled fluids. An engine leaking oil or that had oil spilled while performing routine maintenance will require more time and products to clean. The price of an engine bay detail will increase when applying a ceramic coating to the engine cover and other plastic under the hood.

Trevor Spedden
Trevor Spedden
Trevor Spedden is an author specializing in car detailing content and has a life-long passion for everything automotive. Whether performing basic maintenance on his 2015 Volkswagen GTI, or honing his car detailing skills, Trevor feels right at home in the garage. Depending on the season, you will also find him snowboarding or mountain biking at one of Vermont’s many great mountains.

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