can you use murphy's oil soap to wash a car

[LaWalker]

No, you should not use Murphy's Oil Soap to wash your car. While it's an excellent cleaner for wood surfaces, its formulation is not suitable for your car's paint, wax, or clear coat. Automotive paint requires a pH-neutral car shampoo specifically designed to clean without damaging protective layers. Murphy's Oil Soap is a powerful degreaser that can strip away the wax and sealant that protect your paint, leaving it vulnerable to UV rays and contaminants. Over time, this can lead to premature fading and oxidation.

The primary risk lies in the soap's alkalinity and strength. Car shampoos are engineered to be gentle, lifting dirt away without attacking the paint's finish or the polymer bonds in your wax or ceramic coating. Using a product like Murphy's Oil Soap removes this crucial safety margin. It can also leave a filmy residue that is difficult to rinse off completely, potentially attracting more dirt.

For a safe and effective wash, stick with products made for automobiles. A high-quality car shampoo will provide ample suds to lubricate the surface, preventing swirl marks during washing. If you need a stronger cleaner for heavily soiled areas like wheels or tires, opt for a dedicated wheel cleaner or all-purpose automotive cleaner, which are formulated for those specific tasks without harming adjacent painted surfaces.

Characteristic	Murphy's Oil Soap	Quality Car Shampoo
Primary pH Level	Alkaline (approx. 8.5 - 10)	Neutral (approx. 7)
Effect on Car Wax	Strips it away quickly	Preserves and cleans gently
Intended Surface	Wood, Vinyl, Tile	Automotive Paint, Clear Coats
Rinsing Ability	Can leave a soapy residue	Rinses completely clean
Long-Term Paint Risk	High (fading, oxidation)	Very Low

[SimonAnn]

I tried it once on my old truck, thinking it would be a cheap way to get a deep clean. Big mistake. It took the wax right off, and the paint looked dull and hazy afterward. I had to rewax the whole thing just to get the shine back. It's just too harsh. Save it for your deck furniture and spend the ten bucks on a proper car wash soap. Your car's finish will thank you.

[McElizabeth]

From a chemical standpoint, it's a bad idea. Automotive clear coats and waxes are designed to work with pH-neutral cleaners. Murphy's Oil Soap is alkaline, meaning it breaks down greases and oils aggressively. This is great for wood but effectively dissolves the protective layers on your car. This leaves the paint bare and susceptible to damage from the sun and road grime, accelerating the aging process. Always use the right tool for the job.

[VonAnastasia]

Think of it like this: you wouldn't use dish soap to wash your favorite wool sweater. Murphy's is designed for porous, hard surfaces like wood. Your car's paint is a delicate, sealed system with a clear coat and often a protective wax or sealant. Using the wrong soap is like using a harsh scrub brush on a delicate surface—it gets the dirt off but damages the finish in the process. Stick with shampoos made for cars.

[McJohn]

I get the appeal of using a versatile household product, but your car's paint is a significant investment. Using Murphy's Oil Soap is a gamble that's not worth taking. It might seem fine once, but the cumulative effect of stripping your wax each time will lead to expensive problems down the road, like needing a paint correction. Protecting that factory finish with the correct products is the most cost-effective way to maintain your car's value and appearance over the long term.