A mechanic recently performed a vehicle repair for me. After he was done, he took a rag, sprayed lots of WD-40 on it, and rubbed it onto several of the hoses in the engine compartment (ex. power steering hoses) to clean them off and make them shiny.

I directed him to stop, because I had no idea if that's okay for the hoses.

Is it okay to wipe rubber hoses with WD-40?


WD-40 has 1000's of uses!! (if you listen to their marketing...)

But really, it is safe for rubber and one thing they call out on their website.

Keeps weather stripping and rubber car door seals soft and prevents drying and cracking.

Ok, it's not specifically about hoses, but it is about being safe for rubber. WD40 is just a penetrating oil spray - it's not a caustic rust remover or some aggressive chemical. Just a "water displacing" (WD) oil spray and its generally pretty safe (safe for paint, chrome, rubber, glass, body plastics - most materials cars are made out of).

  • Thanks. I'm definitely not a chemist, but I am/was concerned about it displacing the moisture in the hoses and making them brittle. – RockPaperLizard Mar 5 '19 at 21:44
  • 1
    Well any of the rubber you find in a car should be fine. Natural rubbers might be different, but anything under the hood is made with the understanding that it's probably going to come in contact with oil. – JPhi1618 Mar 5 '19 at 21:48
  • Thanks for the follow-up! – RockPaperLizard Mar 5 '19 at 22:07
  • As long as you don't try to shine up the serpentine belts with it... – Enot Mar 6 '19 at 15:47
  • Especially okay fot hoses that have oil in them like power steering fluid or gasoline. I'd be more concerned about coolant hoses, but it should be OK for them too. – Eric Mar 8 '19 at 20:02

Please use silicone spray for rubbers. WD40 doesn't have the solve it all ability. Not really meant for sensors or rubber even if they state it causes no harm. On the long term it collects dust and its not a lubricant.

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