How to Wash Your Engine Bay: With or Without Water

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Get your engine’s components shining like new in no time
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It’s a little funny that most car owners take super good care of the car’s exterior when it comes to keeping things clean and shiny, but the engine bay—the place where all of the important stuff actually is—gets ignored! Well, not anymore. We’re going to break down the most efficient way to clean your engine bay so that you can keep everything shiny, clean, and running smoothly.

The Best Way to Wash Your Engine Bay

With a cool car, use a dry paintbrush and a vacuum to dust up and remove any dust in your engine. Then, fill a spray bottle with degreasing soap and water. Spray the engine bay and wipe it down. Rinse the excess suds off with a hose set to the lowest pressure setting available.

Section 1 of 5:

Cleaning Prep

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  1. 1
    Start with a cool car. Don’t clean your vehicle when the engine is running or you have just finished driving. Let everything cool down completely before popping the hood to get to work. The last thing you want is to burn your hand on a hot engine component when you’re working. [1]
  2. 2
    Disconnect the negative battery terminal. Use a wrench to disconnect the negative battery terminal. While your car battery can get wet (it gets wet all the time when it rains or you drive through puddles), this will ensure that you don’t accidentally short any electrical circuits or damage your battery with 100% certainty. Cover the battery with a plastic bag when you’re done.
    • Is this really necessary? Probably not, but it’s more about peace of mind. There’s no downside to removing the negative terminal and covering the battery, but if you’re totally fine with getting the battery wet, we completely get it.
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  3. 3
    Protect any electrical components you’re worried about. If you’re going to hose down your engine bay or use any liquid cleaners, you may be worried about ruining electrical components in your engine bay. Cover anything you don’t want to get wet with a plastic bag or thick cloth. You might want to cover the alternator, the air filter, and the fuse box. [2]
    • Is this really necessary? No. Like the battery, your engine’s components get wet all the time. It’s perfectly fine for these components to get wet so long as you aren’t using pressurized water or really soaking anything, but there’s no downside to protecting them, so it’s up to you.
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Section 2 of 5:

Cleaning Your Engine Bay

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  1. 1
    Knock dust up with a paintbrush while vacuuming the engine bay. Pop the engine hood and grab a vacuum or shop vac . Hook the hose attachment up and turn the vacuum on. Hold the hose with your non-dominant hand and use your free hand to brush the engine’s components one by one. As you brush, hold the vacuum hose 6–8 inches (15–20 cm) away from the paintbrush to suck up everything you knock into the air. Work your way around the entire engine bay. [3]
    • Take your time! Treat this kind of like a spa day for your vehicle—work with love and enjoy the process. Your engine bay is going to shine by the time you’re done.
    • Water-free variation: If you don’t want to use any liquid cleaners, ignore the steps below. Instead, after knocking the dust up and vacuuming, use an automotive degreasing wipe to hand wipe all of the especially dirty components.
  2. 2
    Mix a degreasing soap with water in a spray bottle. Use a degreasing soap designed specifically for cars to ensure you don’t accidentally harm anything in your engine bay. Follow the instructions on the soap’s label. Typically, you just mix a teaspoon of soap into a spray bottle of water and shake it up. [4]
    • Milder soaps are probably okay to use on your car, but they won’t do nearly as good a job of removing oil residue and gunk as a car-safe degreaser.
    • If you’re especially worried about keeping your engine safe: Use a cleaner designed specifically for engine bays . Most mechanics just use regular car cleaners (if it’s safe for your paint, it should be safe for your engine), but there are more specialized products if you prefer.
    • Don’t want to buy a special cleaner? A lot of car detailers and vehicle enthusiasts just use Simple Green . It’s a natural all-purpose cleaner that seems to work well.
  3. 3
    Spritz your engine with the degreasing soap. Pop the hood and start spraying the engine bay with your degreasing soap. Spray any areas where there is a lot of oily gunk directly. For areas that weren’t especially dirty, go ahead and spritz them with the soapy water, but don’t worry about soaking anything. [5]
    • Most of these soaps will foam up after you apply them. This is completely normal.
    • If you’re worried about getting sensitive components wet, avoid spraying your spark plugs, the alternator, the filter, and the batter. Aim to spray around any wires or connections.
  4. 4
    Gently scrub the engine components with a sponge or cloth. Throw on some rubber gloves to keep any oily gunk off your hands if you’d like. Then, grab a scrap sponge or washcloth and gently wipe your engine bay. Scrub each surface using a laid-back circular motion. For any areas where the gunk has built up quite a bit, feel free to scrub back and forth a bit. [6]
    • You shouldn’t need to use very much force. The degreaser will do a lot of the work here for you.
  5. 5
    Rinse the soapy residue off with a hose. Grab a hose and turn the water on. Gently spray the engine bay to rinse all of the suds off. You can either spray the water in the air over the engine bay so it falls gently, or just use a really low-pressure setting on the hose. Either way, try to avoid blasting the engine bay with high-pressure water, just to be safe. [7]
    • Repeat this entire process as needed. You can perform this kind of cleaning as many times as necessary to ensure that you get all of the dirt and gunk off.
    • Do not use a pressure washer or a high-pressure setting on a hose.
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Section 3 of 5:

Is it safe to spray water on the engine bay?

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  1. Yes, so long as you don’t use pressurized water. If you use a thin nozzle on your hose to blast water directly on your engine components, it’s possible you dislodge something or force water into an electrical connection that needs to stay dry. But if you just pour water gently or spray strategically using a softer nozzle setting, you should be okay. Your engine bay gets wet every time it rains or you drive through a puddle—it’s all designed to get wet. [8]
    • The big exceptions here are cars made before 2003 and cars with turbocharger engines. These vehicles do not have engine bays that are designed to handle water and they’re usually assembled in a way where the sensitive components are all on the top of the engine bay to keep them close to the hood where they’ll stay dry. Don’t spray water in these vehicles. [9]
    • Can I use a pressure washer? No, it is highly recommended that you don’t use a pressure washer. Your engine bay can handle water, but not the pressure; you could accidentally dislodge a key connection or harm an engine component.
Section 4 of 5:

How often should you clean your engine bay?

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  1. Clean your engine bay whenever you detail your vehicle. As a good rule of thumb, if the rest of your car needs to be detailed , the engine bay probably needs to be cleaned. Cleaning your engine bay shouldn’t take more than 15-30 minutes, so give it a nice degreasing and scrub down before you wash the exterior. [10]
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Section 5 of 5:

Do you have to clean your engine bay?

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  1. Not really, but it does have a few niche benefits. If you never have any leaks, blown gaskets, etc., then your engine bay doesn’t really need to be cleaned. However, there are a few very good reasons to clean your engine bay: [11]
    • It makes spotting future issues a lot easier. If your engine bay is clean, it’ll be a lot easier to spot oil leaks, coolant leaks, and other potential issues.
    • It prolongs the life of the rubber and plastic pieces. Your engine bay has all kinds of rubber and plastic gaskets, connections, and hose fittings, and those pieces can degrade faster over time if they’re covered in gunk that make heat dissipation harder.
    • It just looks really, really nice. A sparkling clean engine bay is a beautiful thing to behold. If you take pride in your ride, give the engine bay some love every now and then.

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      Warnings

      • Do not spray water blindly on the engine bay if your car was made before 2002 or you have a turbocharged engine. To clean these engine bays, use less water than you normally would and just be careful about not spraying any electrical components. [12]
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      • Do not use a pressure washer on your engine bay. The engine bay can get wet, but the pressure can dislodge certain connections and potentially harm your vehicle’s components.
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      References

      1. ↑ https://www.hotrod.com/how-to/refurbishing-your-engine-bay/
      2. ↑ https://www.hotrod.com/how-to/refurbishing-your-engine-bay/
      3. ↑ https://se-r.net/car_info/clean/detail_engine.html
      4. ↑ https://se-r.net/car_info/clean/detail_engine.html
      5. ↑ https://se-r.net/car_info/clean/detail_engine.html
      6. ↑ https://se-r.net/car_info/clean/detail_engine.html
      7. ↑ https://www.hotrod.com/how-to/refurbishing-your-engine-bay/
      8. ↑ https://www.r3detailing.com/is-it-safe-to-spray-water-directly-to-engine-bay-2/
      9. ↑ https://www.r3detailing.com/is-it-safe-to-spray-water-directly-to-engine-bay-2/
      1. ↑ https://www.shinearmor.com/blogs/news/how-to-clean-engine-bay
      2. ↑ https://www.shinearmor.com/blogs/news/how-to-clean-engine-bay
      3. ↑ https://www.r3detailing.com/is-it-safe-to-spray-water-directly-to-engine-bay-2/

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