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How to Detail Your Engine Bay

by

Overview

We spend countless hours detailing the interior and exterior of our cars, but how many people give the needed attention inside the engine bay? Having your engine bay properly detailed not only looks great, but it also helps fight potential corrosion as well. With a few simple tools and supplies, you too can keep the area under the hood looking like it was professionally detailed.

Precautions

I’ve spoken with a tremendous amount of people who don’t detail the engine bay simply because they’re concerned about damaging the car. It only requires a few preventative measures along with some common sense, and you can clean your engine compartment without worry. The biggest concern is that water will short out electrical connections. In most modern cars, key electrical components and housings are tightly sealed from the elements of daily driving. As long as you’re not directing a strong stream of water (or a pressure washer at close range) directly into these components, you will be fine.

Precautionary Tips:

  • If the air intake opening is directly in sight, then you can either stuff it with a towel, or cover it up with plastic wrap and a rubber band (don’t forget to remove it when you’re done!).
  • If you have an aftermarket intake system with an exposed air filter, then cover it up with a plastic bag and secure it with a rubber band.
  • If you have a fully exposed alternator you can either cover it with plastic wrap, or even better yet use aluminum foil. The foil is easier to mold and fit around the alternator without having to tightly secure it.
  • Use the wide spray pattern on your hose nozzle as opposed to a strong stream. You only need a light rinsing as the cleaners and brushes will be doing all of the work.
  • Working on a warm engine is fine, but if it’s hot, then let it cool for a while.

Items Needed

How-To Detail Your Engine Bay

This engine bay has just gotten through a rough Midwest winter, and everything is covered in grime.

Engine Bay Before

First start out by completely covering all surfaces (including the under side of the hood itself) with P21S Total Auto Wash. This is a gentle cleaner that is safe to use on virtually all areas.

Spraying P21S Total Auto Wash in engine bay

Now that everything is covered, let it dwell for a few minutes so it can break down the grime.

P21S Total Auto Wash dwelling on engine bay

Using your Mini E-Z Detail Brush, agitate the heavier buildup. You can use your sponge or mitt for cleaning the larger flat surfaces.
Using a Mini E-Z Detail Brush to clean engine bay

As you can see, the Mini E-Z Detail brush does a great job of getting into all of the hard to reach areas.

Using a Mini E-Z Detail Brush to clean engine bay

After you have brushed and wiped everything down, lightly rinse it all off with a gentle spray of water. Start with the underside of the hood first, and then work your way into the engine compartment. There are plenty of places for dirt and grime to hide, so be thorough with your rinse.

Rinsing degreaser off of your engine bay

If you have a Metro Vac & Blo or compressed air, use it to blow all of the standing water away. If not, then just use your MF towel to wipe it all down. For further drying, you can also start the engine and let it run for a few minutes.

Drying your engine bay with Microfiber

Now it’s time to add the finishing touches to your engine compartment. Spray on 303 Aerospace Protectant to all plastic and rubber, and then wipe it down to reveal a matte finish that is not greasy or oily. This is a tremendous and versatile product that can be used on many areas of the car.

Protecting your engine bay with 303 Aerospace Protectant

For hoses, wires, and other hard to reach rubber and plastic pieces I like to use Chemical Guys Fade 2 Black (this is also my go-to product for the wheel wells!)

Dressing and protecting your engine bay with Chemical Guys Fade 2 Black

All done! Now you have a much nicer looking engine bay that is clean, free from potentially corrosive materials, and protected from the elements.

Engine Bay Detail After Picture

Engine Bay Before and After Photos

Before:

Before picture of an engine bay detail

After:

After picture of an engine bay detail

Before:

Before picture of an engine bay detail

After:

After picture of an engine bay detail

Before:

Before picture of an engine bay detail

After:

After picture of an engine bay detail

Before:

Before picture of an engine bay detail

After:

After picture of an engine bay detail

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Todd Cooperider Esoteric Auto Detail
Todd Cooperider
Esoteric Auto Detail
Columbus, Ohio
EsotericDetail.com

62 comments on How to Detail Your Engine Bay

  1. Osa U. says:

    Awesome write up on detailing. I plan on starting my own detail business and you basically gave me the blueprint to the whole operation. Thank you for such a detailed outline.

  2. Mark says:

    Excellent job! Would using this method the same way be safe for an 07 z06? Outside of the alternator and filter, there seems to be a lot more exposed electrical parts in the z06 compared to this Honda engine. It could only *appear* that way…

    Thanks

    • Yep, pretty much the same…just cover the mentioned components. I cleaned the engine bay on both a Z06 and a regular C6 Corvette last year and all was good. You can even see in the engine photo of the C6 article where the alternator is the only item covered.

  3. mervin says:

    What about cleaning the engine bay for a lexus 1994 ls 400 whats the process?

    • Mervin,

      Just follow the basic guidelines in the article and you should be fine. If an item looks questionable for getting wet, then just cover it up with plastic or foil.

      Good luck!
      Todd

  4. [...] How to Detail Your Engine Bay – Detailed Image __________________ 2010 z34 k23 H&R sport springs / Spc rear camber arms / Ichiba 20mm ver 2 / Berk cbe / Varis cf lip [...]

  5. Nicholas says:

    Could you spray Fade 2 Black to a microfiber towel or foam applicator pad, then apply? My concern is over spray to objects you don’t want the product on. Also, I would advise against using foil in the engine bay. Reason being that it conducts electricity. In a perfect world there would not be any terminals/wires that have a positive potential (positive). 98% of the metal in the engine bay is a ground (negative). If the foil were to connect the two by simply touching both at the same time, you could very likely have a car fire on your hands. So I say to use plastic bags and 3M blue painters tape to be safe.

    • Yes you could spray Fade 2 Black onto an applicator and apply it that way if you wanted to avoid overspray…

      • Eric says:

        To be safe I would suggest disconnecting the battery. Further suggest pulling battery out which would alleviate the problem some else mentioned about water collecting in the battery holder.

        • I’ve never had a single issue with the battery, but feel free to do that if you know what you’re doing. If you’re working on a client’s vehicle however, keep in mind that by disconnecting the battery you can/will erase a lot of memory in things like the radio, GPS, etc. Any time I have to disconnect the battery in my car, I have to reset codes that I can never seem to remember where I wrote them down! This could be a little upsetting to a customer if you give them their car back and they have to figure out how to reset all of these things. Just something to think of…

  6. Bob Hendershott says:

    Some advice please.
    My Mom’s 74 Mustang II (30,000 original miles) just took Bronze in the unrestored original class. Of the the 78 points deduducted there was a 25 point mandatory deduction for the engine being oversprayed.
    The detailer spray painted the engine as favor to us. This happened about a year ago. The has all it’s original white paint, spark plugs and plug wires. What would be the best way to remove the spray paint and not harm the original. Believe me they we find almost any flaw, lost one point for a dirty brake pedal and one point for a dinged step plate on the driver’s side door sill.

    Thanks

    • Bob,

      Without actually having the car right in front of me, I can’t give exact advice on how to approach this because there are simply too many variables. In some cases detailing clay will remove it, but it depends on what surface it’s on. If the paint is on rubber surfaces, you’ll need to try one method, but if it’s on other painted parts you may have to try another. If you need to do a chemical approach, it’s questionable about how it will affect the original paint underneath. Unfortunately I’m unable to guarantee either results or risk in a situation like this one.

      You may want to seek a local restoration professional on this one simply because of the risk factor involved.

      I hope this helps.
      Todd

      • Bob Hendershott says:

        Thanks for your reply.

        Just engine parts & radiator that were originally black were painted.
        Most likely, it is best just to leave the paint.
        We show the car just for fun. It is too bad, but things this happen.
        If you do too well in unrestored original (two gold place finishes) your pushed into concours.
        Then things really get serious, picking rocks out the tires, etc.

        Now, it just hanging out meeting nice people.

        Again, Thanks pardon the bad typing.

        Bob

  7. Art says:

    Todd

    I want to detail the engine bay of my Audi A5 but frankly I’m very afraid. I have read all your articles but still not sure. Any particular suggestion for Audi A5?

    Your comments are always appreciate it

    Art

    • Art,

      If you follow these instructions, you’ll be fine! Just be careful of the air intake, and only use a fine mist of water. Modern cars have their delicate electronics components sealed up…

  8. Art says:

    THANK YOU!

    Fine mist will rinse the TAW.

    I have a good teacher and I will be very careful!!

  9. Todd Jackson says:

    Todd,

    Quick question: I have many polished aluminum parts under my hood. Are the chemicals you’ve used safe for all of my polished parts, and won’t stain them or leave a less-than-shiny luster?

    Thanks so much, what a great how-to!

    Great name by the way, I’m a Todd too =)

    -Todd

    • Hey Todd,

      Any time you’re dealing with un-coated polished aluminum parts, you run the risk of staining when using any heavier cleaners…especially if it gets on them while hot or allowed to dry. If you’ve got polished aluminum under your hood, then I could assume that you already do a good job of keeping it clean under there. If this is the case, you’re in need of more of a light wipedown than a full detail. When working on something like this, I’ll typically just use some Optimum No Rinse pre-mixed in a spray bottle, and then use a soft microfiber towel. If your engine bay is pretty dirty however, you might want to take the safe route and cover those polished aluminum items up as much as possible, and use a dilluted ratio of a product like P21S TAW.

      I hope this helps!

      Thanks,
      Todd

  10. Brian says:

    I covered my air intake,distributor cap and battery on my 73 M-B. After spraying with P21 wash , I rinsed with a soft spray from the garden hose. I started the car to dry the engine but it now runs Very rough and I get black smoke from the exhaust. Did I somehow get water in the carb and if so will running the engine eventually clear things out?

  11. KC Detailing says:

    What about ferrari, porsche, Lamborghini, and such?

    Tim Dodd
    KC Detailing

    • Tim,

      If you’re working with newer models, you can take the exact same approach…just be cautious if you see any exposed electronics. On older ones however (even from the 90′s back), I would be extremely cautious because they weren’t made with the same level of water-resistant electronics as they are today.

      • KC Detailing says:

        Good to know. I have been detailing all of the exotics engines by hand and it takes forever. Even though I am insured, guess I’m just a bit nervous to pressure spray the engine bay of a Murcielago. I could only imagine. “Sir, your car looks amazing, the paint is shiny enough for you wife to check her makeup in the reflection, but it won’t start. You mostly just let it sit in your garage anyways so….” Guys like you and Paul Dalton helped move me from cleaning pigged out 95 Fords to doing full details and paint correction on luxury and exotic cars. It is now rare for me to need my hot water extractor. Thanks a lot Todd!

  12. [...] How to Detail your Engine Bay: Keep your engine compartment looking as good as the outside of the car by following this simple guide. [...]

  13. [...] Underhood Cleaning? How to Detail Your Engine Bay – Detailed Image __________________ 2010 GMC CANYON. Z71 EXT. CAB. 3.7 I5 FIRE RED. AQUIRED [...]

  14. Ryan says:

    Just a comment from someone in the electronics industry [automotive]. Most modern body wiring harnesses exposed to any moisture [under hood], have rubber boots inside the connectors which do not allow any water in at all unless they are dried up and cracked. As an extra measure of precaution, you could use a small plastic bag wrapped around any electrical connections if you’re paranoid about ruining a customer’s vehicle. These rubber boots have been used on Hondas since some point in the 1990s. I can’t speak for American vehicles or other imports.

    I would never point a pressure washer directly at any connector because you can shift the rubber seal out of position and allow water to get in.

    Just my $0.02.

  15. Ryan says:

    There are only 4 key electronics connector mfg in the world – Yazaki, Amp, Tyco, Sebro that are approved for automotive. All of their connectors are sealed for underhood. IF you look you can see their logos on the connectors, and be assured they are watertight.

    Problem is, not sure that all OEMs use water tight connectors – they are 3 times as expensive as normal connectors..just a heads up.

  16. Bruce Annand says:

    Be carefull useing aluminum foil around alternaters, because if you touch the battrey post conection on the back you could short it to ground and cause all sort of problems.

  17. Dennis says:

    This looks like the perfect plan for what I need to do with my 2006 Odyssey. I couldn’t tell but did you cover anything in the pictures above? Can you truly spray down the battery with a garden hose with no issues? I’m also quite leery spraying water (especially since I am an auto novice).

    • Dennis,

      If I remember correctly, everything was pretty well protected from the factory on this Odyssey and I didn’t need to cover anything up. If you’re not comfortable with it all, then you could simply try to wipe down the components with a damp rag to get rid of the majority of dirt and grime, and then protect it as necessary. Most modern cars are sealed and protected from the elements, so a very light spray of water into the engine compartment shouldn’t do any harm when simple precautions are taken.

  18. [...] not that hard. I used Simple Green all over the engine bay, let it sit, scrub and hose it down. How to Detail Your Engine Bay – Detailed Image __________________ 06 CL9 6MT PWP / Ebony w/ Navi – TL-S RSB | Resonator removed | K&N [...]

  19. Matt says:

    I currently cleaned my engine bay in my 07 honda civic si. After I had let the purple degreaser I followed the rest if the necessary steps and it does look better but I noticed that on my engine it has this to it. I thin I may have let the purple power degreaser sit too long on the engine. What can I do to remove that? I tried some simple green but it didn’t remove it. By the way, I used 303 protectant and chemcial guyz as well.

    Thanks,
    -Matt-

    • Did it discolor metal, plastic, other? Some of those degreasers can be very harsh and can permanently stain if not careful.

      • Matt says:

        When looked at up close, the engine has these specs that are a bit cloudy like different shades of gray and murky white. I tried using some simple green to remove but no luck. What would you suggest? I guess last case scenario is I would have to paint the engine valve cover possibly or get a replacement if it comes down to it.

  20. Lee says:

    I have found that leaving the engine running, and then using compressed air to blow the engine bay dry afterwards gives great results. Another thing to consider also with modern cars, is most have their battery’s sit in a “container” of their own where water may not easily drain from. Attention needs to be paid here to either remove the water, or somehow prevent excess water getting in around the battery in the first place.

  21. Marco says:

    How can be cleaned the underhood liner (engine soundproofing)? Is it safe to wet it? Steam?

    • Yes, you can get them wet. Usually they just need a light spray with an APC, then hit it with a stream of water and it will take care of it. Afterwards either blow it out with compressed air, or just leave the hood open for a while so the water can run out of it.

  22. [...] did some research in terms or how to do it, this site was helpful and I was happy with my results: How to Detail Your Engine Bay – Detailed Image There is also other detailing tips on that website. Join AveoForum to remove ads – [...]

  23. [...] How to Detail Your Engine Bay – Detailed Image i followed this, i just put a plastic bag over the alternator and distributor to be safe, and your cone filter if you have one used simple green (from any auto parts store), but i believe any apc will work, just dont let the degreaser/apc dwell too long if youre working in the sun used ez brush to agitate and get to deeper spots, rinsed off lightly with hose after i scrubbed everything, and wiped down with some 303 aerospace [...]

  24. [...] show you? I follow this write up using similar (cheaper) products that I can buy at autozone. How to Detail Your Engine Bay – Detailed Image Reply With Quote     + Reply to Thread « [...]

  25. Charles says:

    This article couldn’t have come at better time! I’ve been putting off cleaning the engine due to lack of knowledge on the subject, but thanks to this post I finally have the confidence to tackle it. Thanks again, Todd!

  26. Garland says:

    Thanks for putting together this awesome guide. The parts recommendations are great. I’m going to detail the **** out of my engine bay this weekend!

  27. Bob says:

    One question, can you wash your engine bay with the engine on or off too? Any pros or cons? If it’s on, how do i cover up an aftermarket intake? Alternator is fine to cover up while running too?

    • Your best bet is to detail the engine while it’s cool…otherwise you risk spotting and staining, or potential damage caused by cold water on a hot engine. Personally, I’d rather take the safe method.

  28. Jon says:

    FYI On LS motors (LS1, LS2, LS6, LS7, etc) the knock sensors are below the intake manifold and WILL collect water if you spray in there. It is a bad idea to hose down an LS motor near the intake because how the knock sensors are designed. That said if you use your head with respect to pressure and direction of water flow you will be fine.

    Nice article BTW.

  29. Devon says:

    Awesome write up i detail cars at a dealership but mostly deal with new cars which have no need for this but i was wondering if this method would work for a 1999 honda civic ex or if there are extra precautions? And again thanks for the usefull information!

    • That should work just fine. Since you work at the dealership, you might want to chat with one of the mechanics to see if there are any specific areas on that car where water should be avoided.

  30. John says:

    I have a 2010 Acura TL AWD and i was wondering if there was anything in particular i should be covering?? from your detailed guide doesnt look like you covered anything on that vehicle. Thanks!

    • John,
      After looking at the engine compartment of my 2012 TL, it doesn’t look like you’d need to cover anything because it’s all already covered! Just use good judgement and you don’t need to flood the compartment with water.

  31. rollin says:

    hey todd what would the procedure on a 92 dodge dakota v8 be? anything i should worry about?

  32. Bill says:

    Todd, I bought a used car that was kept very well inside and out with the exception of the engine bay which has an exposed aluminum block that has a bit of corrosion on it, from reading around I think I pretty much have to deal with it, but if there was anyone out there that knew how to get it off it would be you! Just wondering if you had any thoughts or suggestions, everything else cleaned up so nice and the look is really killed by the look of the engine…

  33. [...] For a step by step guide check out Engine Detailing Guide. A similar guide with pictures is the How To Detail Your Engine Bay article by Todd Cooperider and we have more articles here (engine bay articles). Hope this helps! [...]

  34. Lewis Kincade says:

    I have a ’97 Merecedes Benz E-420. Had a power steering pump that leaked and got on the drive belt, when started to break down. All parts replaced (including the upper radiator hose, which had a small leak from the belt fraying and hitting hose), now I want to clean the engine compartment. Can I follow your basic instructions with the cleaning solvents above?

  35. Orrin says:

    Hey I just was gifted a 1993 GMC 1500. Yeah I know, “why detail it’s engine bay?” Well. I just want to keep it clean and from rusting as long as I can. So I was just wonder if because its older should I avoid using a spray hose and just use a damp cloth or something? Thanks!

  36. RK says:

    Hi,
    Wonderful Post. I own a 2001 Honda Odyssey. Is there any special precaution for this model? Any information/guidance will be of great help.

    RK

  37. […] This Post has some great instructions and information on cleaning your engine bay. […]

  38. Brian Lerczak says:

    Todd Cooperider working on a Honda?!

  39. jeffrey says:

    Lets not forget coil packs!
    Audi S models with the red coil packs
    Gm 4.3 vortec cap and rotor
    VW late 90′s thru mid 2000
    Ford 2.0, 2.2 focus 5.4 triton motors
    Flat head 4cyl where the plugs are on top.
    In the 5000+ cars I’ve done never had an issue other than coil packs. Food for thought.

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