Originally Posted by LeakySeals
If its a new(er) GM truck with the factory wax still somewhat intact don't use oil based sprays like Fluid Film. It softens the coating to the point it rubs off just putting your finger on it exposing bare metal. Another negative (IMO) about oil based sprays is how they stay wet and sticky, attracting sand, dirt, grit like flypaper. In my NH winter conditions thats not desirable. They use a lot of salt and sand on the hills around here which makes working under the truck horrible. I moved on from FF to a product called RP-342. Recommended by a Canadian. Its a military grade cosmoline wax in a spray can. Its self healing, flows good during application. Has no tacky sticky oil. In the cold the surface gets pretty hard so salt, sand, grit beads up and rinses off with water. Wish I had found this years ago.
Pic under the rear bumper after driving through snow, salt, sand.
Just for correction, Fluid Film is not petroleum based. It's made from wool lanolin. I don't use it for rust proofing, but I've known about the product and have a gallon with two small refillable spray bottles in the garage. Fluid Film is a good product and never dries out. A few guys I know here in Western New York use it to spray people's vehicles. I just found out that there is Fluid Film NAS which is used for undercoating. Someone here with more knowledge can possibly comment.
My first Ford, a 1996 F250, I used Carwell for rust proofing annually. I plowed with that truck and whenever the roads dried up, I would take it in the drive in car wash and spray off underneath. Several mechanics would talk about how clean it was underneath. It definitely worked. But I also think washing it off when the road was dry was paramount to keeping it clean.
My current truck, a 2016 F350, I mistakenly let the dealer talk me into the crap Zeibart undercoating and Bedliner. The Bedliner is for a different thread. Rhinoliner, complete garbage.
Anyway, I let the truck go off the Zeibart warranty and had it Carwell coated. I found a few small rust spots underneath Where the tar came off and treated them with Chassis Saver this year before winter. There were also small paint chips on the rockers that I sanded down and painted with Chassis Saver. Next spring, the rockers will get MonstaLiner to protect them before I get Duraflap mud flaps.
I just had my truck oiled a few days ago and I posted it up on Facebook. One guy commented about the oil on my front doors. I had them spray towards the inside of the mirror housings with the mirrors folded to get to the plastic gears inside hopefully. I told them I didn't care about the mess on the doors. Today is day number 2 after the oiling. The truck has pretty much stopped dripping. The oil does dry and leaves behind a anti rust film. They spray inside the body, inside the doors, all wiring to prevent corrosion, the batteries, hinges etc.
While it will attract some dust along the bottom of the doors along the creased metal, I want to see that as that let's me know the product is there. When being sprayed off with water, the water beads off like Fluid Film. I've been talking with those Fluid Film guys and watched videos on YouTube. So the product doesn't drip once dry and you can use high pressure spray to clean off the bottom during winter.
I learned that Krown's product is called T40 and Carwell's is T32. So I'm wondering if they are from the same company and same chemistry. From what they say, the oil is designed to creep and flow into all the nooks and crannies. I'm just wondering how a thicker product does that? I'm 52 now and still do some stuff myself, but I like paying more to have someone with a lift spray down my truck.
I hope all this babbling helps someone with gaining new knowledge. I posted pics on Facebook also so if anybody wants to see, let me know and I'll put some up.