Rick's Free Auto Repair Advice

WD-40 on belts

Never use WD-40 on drive belts or any rubber parts

Everyday I see nutjobs recommending using WD-40 to stop squeaks on rubber parts like suspension bushing and belts. I also see these same whackjobs recommending it on ignition wires to stop misfiring under humid conditions. WD-40 is a petroleum-based product. It’s 50% Stoddard solvent, 25% light oil, and 12-18% LVP Aliphatic Hydrocarbon plus their secret ingredient.

WD-40 doesn’t stop rubber squeaks

Because it’s a petroleum based product you should NEVER use it on any rubber part. Petroleum products make rubber parts swell and deteriorate. If you want to lubricate rubber parts, use a silicone or dry Teflon lube product.

Spraying an oil based lube onto a serpentine or poly-ribbed drive belt may make the squeak disappear for a while, but it doesn’t fix the underlying problem. Plus, it damages the belt. The same applies for ignition wires, Oil based lubes damage the spark plug wire insulation.

Keep in mind that you’re basically spraying Stoddard solvent and a light oil on parts. That’s why it isn’t a very good rust penetrant in my opinion. If you want to break rusty bolts, use a rust penetrant. WD-40 makes a special rust penetrant. If their standard product was such a good rust penetrant, they wouldn’t need to make a separate rust penetrant, would they?

Bottom line to nutjobs: WD-40 should NEVER by used on rubber. Period. The end.

©, 2015 Rick Muscoplat

Posted on by Rick Muscoplat


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