[JamRSW6]

A while back I remember seeing a conversation on one of the forums here about a chassis/underbody coating. Not undercoating but something else to protect the underside of the car from degrading. I have searched but no luck. I am needing it for my 96 Trans Am. It sits outside under my carport, with dual car covers and is on concrete. I am wanting to protect the underbody from the humidity. Anyone remember the thread? Thanks, Jimmy

[SIX8YAK]

POR-15 seems to be the ticket for stuff like that, especially with a little surface rust. I have a friend who is using a cheaper somewhat similar version called Chassis Saver.

[JamRSW6]

From what I recall, this product was not a opaque coating like POR-15. More like a clear/transparent coating. I want it to go on various surfaces but not have the underside of the car just all black. I want the original finished protected but not altered from their original color. I apologize for not remembering where I saw the thread. Jimmy

[64-3Deuces]

You might be referring to wool wax, a lanolin by-product of shearing sheep wool. Discovered in WWII that applying this lanolin kept Navy ship ballast tanks and anchor chains clean and rust free. Good article about this stuff in the January 2018 issue of POCI Smoke Signals. Can be sprayed, brushed, or rolled on and is more or less clear. The commercial name is Fluid Film and available through NAPA and I suspect other auto places as well. Do a search for Fluid Film Napa and all kinds of links come up.

[SIX8YAK]

Originally Posted by JamRSW6

From what I recall, this product was not a opaque coating like POR-15. More like a clear/transparent coating. I want it to go on various surfaces but not have the underside of the car just all black. I want the original finished protected but not altered from their original color. I apologize for not remembering where I saw the thread. Jimmy

Missed reading "not undercoating", woops!

[Stuart]

Fluid Film is one product, there are others.

[Frank R]

Some people use roll on bed liner.

[SR-71]

There was a vender at Norwalk last year with parts of a custom 65 Catalina I believe that he was selling parts from. It seems he had just finished it and put roll on bed liner on the underbody to deaden the sound. One day while driving the exhaust somehow ignited it and almost burnt the car to the ground. Sad to see.

[77 Canamman]

I swear by Fluid Film. I have used it on both of my Sierras. After a combined 6 winters, neither truck exhibited ANY surface rust, let alone scale. It's easy to get in Aerosol form at AutoZone.

[poncho4554spd]

Fluid film works well as previously stated

[dataway]

Just ordered a can of Fluid Film from Amazon after reading these posts. Have a sierra and live up north, so I need something.

[GRNMTGOAT]

Waxoil is good,available black or opaque. All three of my cars are treated,plus we had the fire truck and emergency response vehicle done. Very common in UK and I think Canada,perfect for ‘rust belt’ vehicles.

[Stuart]

I've wondered about the formulation of these products - whether Waxoil is basically the same as Fluid Film or the others (one other brand I know of is Krown - https://www.krown.com/en/ ). I think they are at least all similar, with some sort of waxy ingredient that holds the oily ingredient in place. I've heard the way to do it is to apply the product of your choice, then go drive around on gravel roads for a while to build up a layer of dust on the undercarriage.

When I was a kid I worked summers for an old time farmer. He kept a big bucket of used motor oil and a big brush around, and at the end of each day's work he'd paint his tractor or whatever equipment he was using with that old oil. All of his stuff looked like heck, but they didn't have any rust.

[dataway]

I have an old touch up gun with a large tip in it that I use to spray my truck with used motor oil, basically it's the only thing I've found that works so far. Find a 40 year old car in the junk yard that had an early rear main leak, you can still wipe off the sludge and find perfect condition metal underneath in a fan spreading out from the rear main.

In Canada they used to have places where you could pull your car in and they would spray the underside with oil before winter. Of course this has been banned because it worked.

[Fullsize455]

I can definitely attest to oik being an excellent option in terms of the protection it offers. It does have its downsides of course, and I sure wouldn't want the underside of a nice classic coated with nasty oil, but for a daily driver truck or something it's a great option.

With regard to the OP's situation, I wouldn't think atmospheric humidity would be a real problem for your undercarriage when parking on pavement. Underbody rust is a big problem when parking on dirt because of the constant evaporation and generally wet environment that results, but parking on dry pavement in a carport shouldn't be a problem at all.

[cdrookie]

if there's no underlayment down before they pour concrete it will sweat like crazy during the summer months. I know people with garages where nothing rusts and others where everything is rusty. Neighbor keeps his garage doors open a foot when it's hot out, keeps a little circulation moving, otherwise everything would be dripping. JamRSW6, if you go the Fluidfilm route wear a dust mask or respirator.

[SR-71]

They still spray in Canada they use at least one product I know of called Rust Check,

[JamRSW6]

Thanks to all of you! Yes, it was the wool wax/ fluid film I had remembered.
Any down side to this product? Jimmy

[77 Canamman]

Originally Posted by JamRSW6

Thanks to all of you! Yes, it was the wool wax/ fluid film I had remembered.
Any down side to this product? Jimmy

The ONLY downside is if your vehicle has a black wax dipped frame, such as the GM trucks from 1999-present. The Fluid Film will dissolve the already somewhat fragile coating. Also, it has been known to dry out rubber, so avoid spraying on body mounts and brake hoses. Brake and exhaust surfaces should also be avoided. Any painted or bare metal can be sprayed for excellent protection. I spray control arms, axle housing, floor pans, bolt heads, inner bumper surfaces, inside doors, tailgate, rockers, etc.

[64-3Deuces]

Originally Posted by 77 Canamman

The ONLY downside is if your vehicle has a black wax dipped frame, such as the GM trucks from 1999-present. The Fluid Film will dissolve the already somewhat fragile coating...

Would a 2008 GMC Envoy be considered a truck? It is a full frame vehicle and basically and enclosed truck. Never heard of the wax dipped frame-what is that exactly?