Piston Slap: Sounding Off on Off-Gassing?


Michael writes:

My 1997 Porsche Boxster steering wheel gets very sticky on hot sunny days; it can even leave a black residue on the hands. It is not a leather-covered steering wheel, though. The stock wheel is some kind of synthetic material, almost a super dense foam rubber. It is somewhat springy to pressure. I was hoping some chemical would transform the outer surface to its original.

A cover feels too thick, and I don’t really want to buy another wheel. Cures?

Sajeev answers:

This should be an easy one, unless the comments section tells us otherwise! I’ve addressed the same issue on the airbag cover of the C5 Corvette. So before we proceed, can we all enjoy the irony of the Porsche with premium materials having the same off-gassing issue as the Corvette with an inferior interior? (The Porsche indeed has nicer guts, but age conquers all opinions of plastics and vinyls.)

Back to my experience with successfully cleaning off-gassed “goo” from the airbag cover of a C5 Corvette. Long story short, my experimentations ended after just a few minutes, thanks to a can of carburetor cleaner (yes, really) and a plastic scraping tool (like the ones used for drywall) to shed off that gooey mess. After I was done, the airbag cover looked perfect. Even the detailing in the embossed Corvette logo looked like new.

Maybe you’ll get lucky and treating your wheel won’t require such an aggressive chemical. To avoid overkill, I would start by slapping on some latex gloves, getting some shop towels, and trying these chemicals in an inconspicuous area first.

  1. WD-40 (least aggressive)
  2. Brake cleaner
  3. Carburetor cleaner (most aggressive)

Once you’ve ascertained how aggressive your chemical needs to be, then you can turn your attention to the steering wheel. To start, I’d turn it upside down (rotate it 180 degrees) and work on the bottom of the rim, just to validate the investigation you did on the inconspicuous area first.

Follow up your work with a dab of abrasive hand cleaner to get any residue off the wheel, then rinse with water to finish it off. I have done this exact procedure three times now and #3 has always done the trick. Be conservative on how much cleaning agent you use, and work in small areas to keep the residue from making a bigger mess in your Boxster’s interior. Good luck!

Have a question you’d like answered on Piston Slap? Send your queries to pistonslap@hagerty.com—give us as much detail as possible so we can help! Keep in mind this is a weekly column, so if you need an expedited answer, please tell me in your email.


Check out the Hagerty Media homepage so you don’t miss a single story, or better yet, bookmark it. To get our best stories delivered right to your inbox, subscribe to our newsletters.

Read next Up next: Fiat Thinks Outside the Box with new Panda and Camper Concepts


    I concur, unless instead of a buildup of off-gassed “goo”, the original “surface” on the wheel has just worn down to a sub layer with use. This has happened to me (albeit not on a Porsche) and no amount of cleaning will solve it.

    I use denatured alcohol on my C3 Corvette steering wheel. It is made with a hard black plastic material – not dense foam, but it may work on the Porsche wheel also.

    That is also worth a shot. I would recommend trying anything before carb cleaner, but sheesh, at some point I ran out of options and that stuff just broke it down like it was nothing.

    May I suggest a less toxic item to use.

    Lemon juice.

    Most C5 owners have been using lemon juice as it has enough acid content to clean the cover but not damage anything.

    Also use 303 protectant to finish it off.

    Carb and brake cleaner is a bit harsh.

    Also for color interiors these covers may just be painted or coated. Like the slate C5 interior may lose its color if you use anything too harsh.

    Same problems with 90’s BMWs and Miata. I think it’s more than off gassing. It looks like manufacturers used a spray coating to give a soft ‘feel’ to hard plastic. BMWs are notorious for this stuff just wearing off. Mazda put it on the dashboards of it’s leather interior Miatas, with similar results. There are even companies selling lettering transfers for consoles and dashboards

    Off-gassing. No Taco Bell or Mexican Food jokes? What gives?

    Beans, Beans, Good For Your Heart! The more you eat them the more you off-gas!

    Remember that time the Enterprise was venting drive plasma? :^)

    This issue only affects people who don’t typically eat a good amount of legumes. Eat more, your body regulates.

    they put plasticizers in those plastics to keep them flexible – over time some of the plasticizer migrates to the surface – regular isopropyl alcohol from a drug store typically works well – plasticizer migration is also a major contributor to the “fogging” you get on the inside of the car windows – the OEM’s have dramatically reduced these materials on recent models

    Yes, it must be an aging out material problem. The steering wheel never got “sticky” 40+ years ago, but it started to become noticeable over the last 10 years after the car has not been driven for a while. (I know – I should be driving it more, but we only have 6 months of nice weather here)
    Everything else in the interior is fine. Original leather seats, padded dash and door panels, etc are fine.
    GM probably didn’t know or care if it would last 50 years back then. They wanted to sell you a new car every 5 years.

    A lot of expensive European vehicles had issues with a supplier or suppliers that used a plastic compound that was later discovered to not be very long-lived. Google “Ferrari F355 sticky parts” for at least one example. I’m not sure if this exactly the same, but the reside from touching these parts is almost like a tar. The problem is extensive enough that there is a cottage industry for after-market replacements made with a different process. Those who prefer 100% originality can purchase OEM parts and reset the clock on the ticking time bomb.

    Ferrari owners are all to familiar with “the stickies” caused by soft-touch coatings applied by the factory on myriad interior components over the years. The best, and least potentially damaging, solution I have found is 90% denatured alcohol applied with paper towels, Q-tips and a little elbow grease. If you don’t mind throwing them away afterward, microfiber towels also work well. Once done, some low-gloss Armor All will provide a good look and help seal the surface.

    My C5 had the sticky air bag cover. I used Goof Off Heavy Duty Remover. Made to remove sticky residue, also ink, lip stick, grease, and oil. A few applications and some rubbing was all it took. I would be afraid to use brake cleaner!

    I’m glad goof off worked for you, I think I tried it and it didn’t work very well for me (but its been a while since I did this). Don’t worry you can use carb cleaner, and my perfect looking airbag is proof.

    My steering wheel on my 1976 corvette has that problem and I hope those products do the job.
    I’ll try them 1 at a time to see which one works best if not I’ll get a steering wheel cover.

Leave a Reply

Your email address will not be published. Required fields are marked *