I was wondering how often i need to undercoat my car, once a year or every two years.? I live in Canada
Once every year and use an oil based undercoating such as Fluid Film or Krown. Spray it on in the summer when it's warm outside so the oil is warm and can creep deep inside areas of the car's body.
The nice thing about oil based undercoating is you don't have to wash the underbody of the car. The oil will keep salt and water from sticking to the frame. Oil is a water displacer which is why water beads up on top of the oil and keeps the metal surface from rusting. The last thing you want to do is power wash the oil off.
Don't put rubberized undercoating on your car. Salt and water will get trapped underneath the rubber and rot out the car's body.
I'm removing my Krown recommendation after seeing this video. Krown didn't prevent rust very well. https://youtu.be/oXlhmbvdKBo . Repair Geek has been documenting how well Fluid Film has prevented rust on his truck for 7 years. https://youtu.be/QqbnNNZRF-c
Ultimate Guide to applying undercoating. https://youtu.be/EbIvELAXWmc
@oskool I've been using Fluid Film for quite a few years and it really does help slow corrosion, even on areas that already have rust. I apply it once a year in the fall using a spray gun. Also highly recommended by Eric O. of South Main Auto.
@chucktobias I've come to learn that Fluid Film primarily has Lanolin in the formula, which is a wax secreted by sheep. Who would have thought that sheep wax is one of the best rust protection coatings on the market!
Well, undercoating generally lasts for quite some time. The main thing is you have to rinse the salt off cuz you use salt in the winter and the roads all the time and that's what eats them up. My advice is to buy a monthly subscription to a car wash. That's what I used to do in Niagara falls. So you could rinse it off as much as you want
