Does Fluid Film Work Against Rust?


Well-Known Member
I drive a Honda CR-V and my boyfriend drives a Nissan Frontier and we'd like to get them undercoated to prevent them from rusting. I've been doing some reading about different types of undercoating and Fluid Film has come up time after time. Is this coating any good? How long does it last? If we have our vehicles sprayed once, will that last forever?


Well-Known Member
Fluid Film is generally touted as a once per year rust preventative, so spraying your vehicles only once won't cut it. It's not like the rubber undercoatings we're all so used to. This film is more of an oil. It's actually wool wax, so yes, it does wash off after some time. It's great for rust prevention because unlike rubber undercoating, you can spray Fluid Film in pretty much anything. It doesn't eat away at rubber lines and it's easy to wash off things you don't want it on. The best part of this product is that you can spray it on your shocks, struts, springs, brake calipers, frame, and just about anything else that begins to rust underneath a car or truck. You can't do that with rubberized undercoating. Where I live, I see a lot of pickup trucks that have rusted out rear bumpers. This is because the road salt finds its way up inside the bumper and sits there forever chewing away at the metal. You can't generally undercoat that area with traditional undercoating. With Fluid Film and other oily undercoatings, you can. Simply spray it up there. You can spray the transmission, rear ends, gear boxes - whatever you want.

But here's the thing. Don't spray your vehicles in the spring. Driving around in the rain will wash it off. You want to spray as close to freezing as possible so the only thing you encounter is snow. The cold will also keep the oil (or wax) firm, so it's less likely to wash off. It's also not a set and forget type of product. You need to keep tabs on your vehicles' undercarriages to see if there are any dry areas. If there are, you might need to reapply.

I will tell you that I have sprayed vehicles and trailers that haven't moved very much in years and it looks like I sprayed them yesterday. So treating things that are in storage or that don't move is a great idea. It's just that warm water that this stuff doesn't like.


Well-Known Member
I have been spraying cars and trucks with Fluid Film for years. Hundreds of different makes and models. I have applied it to both of your vehicles, so I thought I'd chime in here. Basically, with the CR-V, you can access much of what needs spraying without putting the car on a lift or even jacking it up off the ground. You won't get to much from underneath the front of the car, but you can access underneath the engine and all of the front suspension areas from the sides. As you move to the rear, you'll have access to pretty much everything from the rear sides and the rear itself. Most of what's vulnerable is underneath the back of the car. The fuel tank, suspension, sway bars, tow hitch if you have one, brakes, struts, and everything else is in plain site. As for the Frontier, you certainly don't need to jack this truck up at all to get to everything. Just put a piece of plywood or something on the ground and start spraying. This truck is definitely high enough off the ground to reach all that needs to be reached. Basically, I'm saying that if you bought a gallon or two of Fluid Film, an undercoating spray gun, some air line, and an air compressor, you could do this job yourself this year and every year thereafter. And all this equipment would probably cost the same as what a garage would charge you for only one application on both vehicles. Dewalt has got a great little pancake compressor that's perfect for this type of job. Good luck.