Cuci engine with water hose – can you really do this?

<em>Cuci</em> engine with water hose – can you really do this?

Once again we have found ourselves confined to the comfort of our own homes. We trust that you’ve managed to occupy some spare time to do meaningful things, be it reading, cleaning the house, play computer games, binge watching movies, or learning to cook. There’s more time now to cultivate new hobbies, but since this is an automotive website, we’ll keep the topic relevant.

The subject pertains to car care, or more specifically, the not-so-delicate process of cleaning a car engine bay. Over the years, there have been multiple videos of car wash centres hosing down an engine bay with water, sometimes even with a pressure washer! Most of the time, these were met with a lot of flak from the community, but really, it has been going on for decades.

Is it really okay to hose down an engine bay with running water? Will it damage any mechanical components, or will it cause some of the electrical circuitries to short? Well, generally, we don’t recommend running a stream of water over the engine bay because it’s not mentioned in any service maintenance schedule. But we wanted to know what the automakers think, so we reached out to Proton for official comments.

Interestingly, Proton says it is not harmful to run a stream of water over the engine bay, provided you follow some basic but crucial dos and don’ts. What you don’t want to do is use a pressure washer, because the pressurised stream can easily find its way past gasket seals or plastic covers that protect sensitive components, such as the ECU, fuse box, ignition wires, and sensors.

<em>Cuci</em> engine with water hose – can you really do this?

Before you even consider cleaning your car’s engine bay, first make sure it is cool to the touch – never wash or clean while it’s hot. Hot metal expands and can crack in direct contact with cool water, and that’s just the least of your problems, really. In more severe cases, spraying cool water on a hot engine may even cause warpage, potentially causing oil leaks from the rocket cover gasket, which causes oil burning smell.

Taking proper measures to seal off these sensitive areas will help prevent water entry into the engine chamber. You’ll also want to cover any electronic or electrical components, such as battery terminals and the fuse box with some form of protective film, like a cling wrap for example. Also be sure to close off any open air ducts, and seal the air filter cover tight. Skipping this step may risk water entering the spark plug wells, causing misfiring, loss of power, and rough idling.

For an extra peace of mind, consider protecting your alternator as well. While it is designed to handle splashes of water from regular driving, it isn’t meant to handle large amounts of running water at one go. There have been many reports of alternator failures resulting from flooding the engine bay with water, so consider yourselves warned.

<em>Cuci</em> engine with water hose – can you really do this?

Once you’re certain these conditions have been met, Proton recommends using a low pressure garden hose to remove loose dirt. Don’t be too generous with the stream of water, though, just use however much is required to get the job done. You may also go over stubborn grimes with a soft bristle brush. After that, remember to wipe things dry, and refrain from starting the engine immediately if you can (some drying time is recommended).

There are other, much safer ways to go about cleaning the engine bay. There’s a myriad of dedicated cleaning products you can buy online, and all your car usually needs is a few microfibre towels and the good old elbow grease. A simple cleaning process takes around 15 minutes, so we much prefer going this route than flooding the heart of your vehicle with water.

If you think your engine bay needs some serious cleaning, we recommend you at least take the car to an authorised service centre, or a professional detailing centre if you have the budget. Otherwise, we’ll put together a simple do-it-yourself guide soon, so stay tuned for that. In the mean time, where do you stand on the matter? Have you had your engine bay cleaned, or God forbid, damaged with a stream of water? Let us know, below.

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Matthew H Tong

An ardent believer that fun cars need not be fast and fast cars may not always be fun. Matt advocates the purity and simplicity of manually swapping cogs while coping in silence of its impending doom. Matt's not hot. Never hot.



  • Veyron Owner on Jan 18, 2021 at 7:38 pm

    Since PKP started 17 March 2020 last year, I’ve been detailing my own car every two weeks… all the way down to the wheel nuts and paip ekzos.

    One happy car with one equally happy owner.

    Like or Dislike: Thumb up 36 Thumb down 2
    • Civic Turbo 2018 on Jan 19, 2021 at 1:24 pm

      I don’t see any DOs and DON’T after reading through. Disappointed!!

      Like or Dislike: Thumb up 6 Thumb down 4
  • Haidi on Jan 18, 2021 at 7:42 pm

    Oh yes… Looking forward to see your guide, will definitely clean my handsome sportscar ;P in this MCO 2.0. Thanks in advance.

    Like or Dislike: Thumb up 4 Thumb down 1
  • alwin on Jan 18, 2021 at 8:54 pm

    Hi Proton, Leave us an video

    Like or Dislike: Thumb up 5 Thumb down 0
  • Old school on Jan 19, 2021 at 1:04 am

    What is the benefit to clean the engine with water hose other than to make it less dusty. It won’t improve the engine’s performance.

    Like or Dislike: Thumb up 1 Thumb down 9
    • Haidi on Jan 19, 2021 at 9:38 am

      When I look at my car’s clean & shine engine bay, I feel refreshing! :D
      No kidding.

      Like or Dislike: Thumb up 12 Thumb down 0
    • Shepherd on Jan 19, 2021 at 9:51 am

      Easier to check if there is oil/coolant leakage, cracks, wear & tear of engine parts/components.

      Like or Dislike: Thumb up 11 Thumb down 0
    • azrai on Jan 19, 2021 at 12:11 pm

      E.g. Grease and oil on rubber parts especially hoses can degrade it. You want a burst fuel line? Oil on hot manifold can start a fire.

      Like or Dislike: Thumb up 4 Thumb down 0
  • Newme on Jan 19, 2021 at 8:29 am

    Before proton talks so much about using water hose to clean, ask them to settle turbo hose problem first.

    Cut and paste- “Nak Hos Turbo Pun Tunggu Lebih 2 Minggu, Lelaki Ini Tulis Surat Terbuka Kepada Proton”

    Like or Dislike: Thumb up 4 Thumb down 16
    • Avenger on Jan 19, 2021 at 11:12 am

      Your issue is 4 years ago story. 4 years ago dah settle lah. You seriously ran out of issues to shoot proton isit?

      Like or Dislike: Thumb up 6 Thumb down 4
  • ex VGM staff on Jan 19, 2021 at 10:28 am

    one key word left out though :- degreaser.

    especially when there are signs of oil or grease which is hard to clean with ordinary detergent.

    and never let water into spark plug cable opening. its like snake bite. you will suffer once you start the engine after with jerkiness at a certain bandwith.

    Like or Dislike: Thumb up 2 Thumb down 0
  • Curious driver on Jan 19, 2021 at 11:45 am

    Should we stop driving when raining?Cause hot engine meet cold water? Just curious…I don’t want warp engine top cover, leaking engine oil.

    Like or Dislike: Thumb up 4 Thumb down 3
  • Vanguardian on Jan 19, 2021 at 11:51 am

    Water and electrical wiring/component are never good fren. Cuci if you must, just be careful when cuci engine.

    BTW, dont cuci engine when the engine is hot, unless you are planning to “upgrade” engine.. heheheh

    Like or Dislike: Thumb up 3 Thumb down 0
  • potato on Jan 19, 2021 at 12:35 pm

    also don’t forget to cover the bonnet sensors. many alarm system to haywire after an engine wash. it’s usually located near where you unhinge the bonnet (front mid).

    Like or Dislike: Thumb up 2 Thumb down 0
  • izhar on Jan 19, 2021 at 2:33 pm

    Iswara after engine wash sure wiper on by itself and cannot turn off until no more moisture.

    Like or Dislike: Thumb up 4 Thumb down 1

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