Fluid Film vs Woolwax vs NH Oil Undercoating [Explained]

Fluid film, woolwax, NH oil or any other car undercoating product, is a very important one and it does a very good job of protecting your car, especially over the winter months of the year.

So, if you’re driving say somewhere north and there’s a lot of snow and salt on the road well if that salt comes in contact with any bare metal that you have on the bottom side of your car it’s going to rust or worse, get corrosion.

While there are various products available in the market, Fluid Film, Woolwax, and NH Oil undercoating are three popular options.

In this article, we will compare Fluid Film, Woolwax, and NH Oil undercoating to help you decide which product would be the best for your car.


Fluid Film is made from lanolin, which is extracted from wool. It is a non-toxic, solvent-free, and environmentally friendly product that can be applied easily using a spray gun or brush.

Woolwax is also made from lanolin, but it contains additional additives such as corrosion inhibitors, solvents, and thickening agents. Woolwax has a thicker consistency than Fluid Film and is applied using a special spray gun.

NH Oil undercoating is made from mineral oil and is designed to penetrate deep into the car’s metal surfaces. It also contains corrosion inhibitors and is applied using a spray gun.


Fluid Film is the easiest of the three products to apply. It can be applied using a spray gun or brush and does not require any special equipment. The product is thin and penetrates into hard-to-reach areas, making it ideal for undercoating.

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Woolwax requires a special spray gun that can handle the thicker consistency of the product. The gun also needs to be cleaned regularly to prevent clogging. However, once applied, Woolwax forms a thick, durable layer that provides excellent protection against rust and corrosion.

NH Oil undercoating also requires a special spray gun, but it is thinner than Woolwax and easier to apply. The product dries quickly, and you can drive your car immediately after application.


All three products are effective in preventing rust and corrosion, but they work differently. Fluid Film and Woolwax form a barrier that prevents moisture and air from reaching the car’s metal surfaces. NH Oil undercoating, on the other hand, penetrates the metal surfaces and displaces any moisture that may be present.


Woolwax is the most durable of the three products, forming a thick layer that can last up to 12 months. Fluid Film undercoating requires more frequent reapplication, with Fluid Film lasting up to six months.

NH Oil undercoating Will provide you with superior protection. It remains soft. It compensates for heat and will not dry or crack like traditional hard coatings and substantially reduce the corrosive effects your vehicle is subject to during winter conditions.


In conclusion, Fluid Film, Woolwax, and NH Oil undercoating are all effective products for car undercoating and rust prevention. Which product you choose depends on your specific needs and preferences.

Fluid Film is the easiest to apply and the most environmentally friendly of the three, but it requires more frequent reapplication. Woolwax is the most durable, but it requires a special spray gun and is more expensive. NH Oil undercoating is the thinnest and easiest to apply, but it may not be as effective in preventing rust and corrosion as the other two products.

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