The water-displacing spray WD-40 has many uses: it’s a lubricant, rust preventative, penetrant and moisture displacer, and you might find yourself wondering whether it can be used on your car.
When it comes to using products on your car, there’s always a concern about damaging the paint job.
However, WD-40 will not harm your car’s paint, and it’s perfectly safe to use.
Is WD-40 safe to use on my car?
WD-40 has many uses for your car. It can be used instead of car polish to fill in small scratches and scuffs, and it’s also great for removing bird droppings, dirt and dust, bugs, and even tar.
Not only is it safe to use on your car’s exterior, but it’s also fine to use on your car’s interior, too.
The history of WD-40
WD-40 is a household name today, but do you know what it stands for? The ‘WD’ stands for water displacement while the ‘40’ comes from the 40th attempt at making the formula.
WD-40 was invented in 1953 as part of the Rocket Chemical Company (later renamed WD-40 Company), in San Diego, California.
The formula was kept as a trade secret and was never patented, but we know it’s composed of various hydrocarbons. It was originally designed for use on aircraft, specifically to be used by Convair to protect the outer skin of the Atlas missile from rusting. However, WD-40 was later found to have a whole range of household uses and was therefore made available to consumers in 1958.
While WD-40's formula - a unique blend of lubricants - is a trade secret and hasn’t been altered over the years, the main ingredients are displayed on the aerosol can that the product comes in and includes:
- 45-50 % low vapor pressure aliphatic hydrocarbon (isoparaffin)
- <35% petroleum base oil (non hazardous heavy paraffins)
- <25% aliphatic hydrocarbons (same CAS number as the first item, but flammable)
- 2-3% carbon dioxide (propellant)
The original copy of the formula was moved to a secure bank vault in San Diego in 2018. However, because the composition has always remained a secret, it was not patented during its invention in 1953, and it is now far too late for the manufacturers to do so.
Why is WD-40 safe for my paint job?
WD-40 shares many ingredients with regular car polish, including oils and hydrocarbons that seep into small areas to fill in cracks, and anti-corrosive agents that can reduce oxidation.
This means WD-40 can be used to fill in deep scratches on your car’s exterior. While it won’t fix the scratch, it’s a good short-term solution that prevents water from accessing the bare metal structure of the car, which could eventually lead to rust.
While WD-40 contains elements that could damage your car if applied ALONE, such as kerosene, the perfect blend of ingredients prevents this from happening, and the formula is fully safe to use on your car’s paint job.
What else can I use WD-40 for?
While WD-40 is great for filling in cracks and scratches on your car, car owners also use it for a range of other reasons:
Enhance the paint’s color
WD-40 can be used as a car wax, which amplifies the luster of paint and enhances the overall color. When applied on top of paint with a clear coat, the paraffins in the WD-40 solution produce a shiny hue that can mimic that created by wax.
Improve hydrophobic properties
WD-40 is commonly used to improve hydrophobic properties on non-protected paint surfaces. Spraying it on the surface of your car will help reduce the potential of bugs, bird droppings, tar, and tree sap from sticking to paint, and it will also bead water to some extent as well.
Remove bugs and stains
WD-40 is also a great tool for quickly removing bug splatters, bird droppings, and other sticky stains. Simply spray, let the formula soak in for a few minutes, and then wipe the area clean.
As a degreaser, WD-40 will also swiftly clean up splattered oil and other water-insoluble substances such as grease.
Extend the lifespan of wipers and gaskets
Frequent exposure to elements such as UV rays and oxygen can leave door trim gaskets and windshield wipers vulnerable to wear and tear.
As they age, the gasket material will begin to dry out and will eventually crack and begin to fail. Using WD-40 on these areas can help keep them protected from the elements. Simply spray some onto a cloth and then wipe the areas.
Maintains spark plug
DIYers who complete their own maintenance use WD-40 to help clean spark plugs. As they get older, condensation tends to gather in the spark plug which can lead to poor performance. Therefore, a quick spray of WD-40 can be great for treating condensation issues if you have an older engine with weak internal seals.
It’s a universal cleaning tool
WD-40 is great for cleaning a range of things, from rust on your license plate, to corrosion on your steering and suspension parts.
The downside of using WD-40 on your car
The one thing to bear in mind when using WD-40 on your car and any other surfaces is that it contains oils, and these oils are notorious for harboring dirt, dust, debris, and other contaminants.
This can lead to WD-40 having the opposite effect to what you intended. The areas you sprayed could end up dirty and sticky.
When it comes to scratches, WD-40 will protect the dent for a couple of days, but during this time it might also gather dirt and dust, meaning you’ll have to wash it off.
Removing the WD-40 will be difficult, so you’ll need to use an automotive detergent car shampoo, also known as a wax-stripping or prep shampoo.
WD-40 is an excellent formula that has many uses both for your car and general household tasks.
It can be used to lubricate, clean, and protect surfaces, and it won’t damage your car’s paint job. The only thing to bear in mind is that WD-40 can also attract dirt due to the oils it contains - so you may need to remove it again in a couple of days.