Spray Oil Treatment

[Deleted]

So we went to pick up our new-to-us truck, and the dealer highly recommended the Krown oil underbody coating, or a DIY job with used motor oil.  The oil is re-applied annually, and is supposed to coat the rust and keep water from getting in and making the rust worse.

The dealer was really down on permanent undercoatings.  This guy explains why permanent undercoating isn't always a good idea:  www.youtube.com/watch?v=YYdAGnp1RJM

I've found a few products that might be useful:
There's the Krown dealerships.  (https://www.krown.com/)
There's the FluidFilm DIY product.  (http://www.fluid-film.com/)
Spray Gun and Wand for getting inside cavities (http://www.kellsportproducts.com/Spraygun.html)
Spray Gun and Hose: www.eastwood.com/undercoating-gun-and2-hoses-bottle.html

What I've not found is a lot of instructions on the DIY products or experiences with it.  Is this something someone with moderate mechanical ability and an air compressor can do?  How much overspray mess am I looking at if I try to do this in my own garage/driveway?  How bad is the runoff for my soil?

This year we're probably going to have the pros do it, but in the future we may have more time than money, and the sprayer is a one time investment that will last several years, and we can do the used motor oil version if we don't have materials cash.

[Deleted]

Thanks for the information with those links. I have an old one that needs it pretty bad, so I hope someone with this experience will respond.

[Deleted]

The few tips I've found are to not spray the exhaust system or the door seals. Look for existing holes in the frame to get a wand/hose into, and if you can't do that then drill holes in discrete places and paint the edges of the hole. An unrelated video said most paints don't bond properly to prevent rust, they recommended "miracle paint".

[hermitjohn]

All I know is that when I lived up in rust belt, the old beaters I drove were most solid where the oil leaking out of the engine sprayed back on the body/chassis as I drove down the road. The Chevy engines especially leaked lot oil in their old age. Buy oil by the case and as one guy said, you changed oil while you drove the vehicle. Couldnt afford to drive one of those anymore, just the cost of the motor oil alone would be prohibitive.

[Deleted]

I been using fluidfilm for about a year now. It is a  lanolin based oil, good stuff but you need to treat the truck frame more than once per season IMO. 

All my cars will be getting a underbody coating before this winter. 

[Deleted]

How do you know when it needs re-coating? Do you do the entire underside or are there areas you avoid?

[Deleted]

Sept 4, 2015 16:56:02 GMT @dlskidmore said:

How do you know when it needs re-coating? Do you do the entire underside or are there areas you avoid?

Around the wheel wells it gets washed of over time, you will notice it looses its sheen. The directions on the fluid film can say avoid spraying on rubber (like body mounts), and also there no need to spray on the exhaust.

I buy aerosol cans of it, for convenience. I use it on a wide range of things in my repair shop

[Deleted]

The real appeal of getting the spray gun is the ability to use waste oil as the material. I might go for the spray cans if I was using fluid film.

[Deleted]

I've been hesitant at putting anything under there that might harm the rubber bushings etc., but after 20 years, I probably need to do something even if its not entirely the right thing to do. Thanks for the info.

[Deleted]

I've heard that the bushings underneath are mostly oil resistant, and only the door seals suffer from being sprayed.

[Deleted]

The longer you wait the more issues you'll have. It only slows progression of rust, it can't undo past damage or preserve the truck forever.