Undercoating has worn away. Touch-up or remove it?

[freewayman]

I have a year old F150. I had rubberized undercoating done when the truck was brand new, however the undercoating has worn away significantly after a year much to my surprise. There are numerous rock chips in undercoating in the wheel wells, and around 10-20% of the coating has completely worn away on the frame. I'm not too concerned about the wheel wells as its a aluminum body truck, but the frame is still steel. I want to keep this truck long term and drive it until the wheels fall off.

As such I am having trouble deciding what to do. It seems like the proper thing to do now is to remove the remaining undercoating completely, as now that it is chipped and worn to my knowledge moisture can start to creep under and get trapped, accelerating rust. However, in the places where it is worn and overall there is minimal to no rust. So I'm curious how bad it would be long term to just touch it up with some undercoating from a spray can. Seems like removing the rest of the undercoating would be a complete chore, and not sure if I can find a shop willing to do it. Haven't asked around yet but I'm assuming it will be a lot of $$$.

Here is a quick video to show where it is worn. The brownish looking areas are where there is still undercoating (it tends to attract dust). The black is where its bare steel:

 

[Rust_Belt_Pete]

is this aftermarket?

 

[Danno]

Not a fan at all of these apply once coatings.
If it were my truck, I would use the annual oil like coatings such as Krown. It will creep into any gaps your original coating may develop.
Other thing I would do is try to keep road debris off your truck. Bigger mud flaps, side steps, wheel well liners all would help.

 

[freewayman]

is this aftermarket?

Yes. Got it done by a detailer when the truck was brand new.

 

[freewayman]

Not a fan at all of these apply once coatings.
If it were my truck, I would use the annual oil like coatings such as Krown. It will creep into any gaps your original coating may develop.
Other thing I would do is try to keep road debris off your truck. Bigger mud flaps, side steps, wheel well liners all would help.

I was considering Fluid Film, however I asked them and they advised against it as they said it would penetrate the existing rubber undercoating and separate it from the frame. Not sure if Krown has similar properties to that but I will ask them.

I try my best to keep the undercarriage clean however it has been a constant battle as I lived off a dirt road for a year. I pressure wash the undercarriage weekly for what its worth but I agree I could do better with prevention as well

 

[Danno]

I was considering Fluid Film, however I asked them and they advised against it as they said it would penetrate the existing rubber undercoating and separate it from the frame.

Kind of what you want to do, right?

 

[freewayman]

Kind of what you want to do, right?

Yes, but not sure if it would just get rid of it completely or just swell everything up which might make it worse for what its worth.. I just moved to Lower mainland BC from southern Alberta and neither of these places use much if any road salt.. therefore I'm tempted to just let the undercoating be and patch it up to keep the sound deadening properties. There is a lot of rain on the coast however so I'm still hesitant as I'm afraid moisture will get trapped under, that being said i did a few spot checks underneath the coating (it's quite thin so easily removed with a fingernail) and the frame underneath is pristine.. so I really dont know.

 

[freewayman]

Kind of what you want to do, right?

Also is Krown something you can purchase in stores and apply yourself? I can't seem to find any places out West that deal with it at all, the closest one is 10 hours away in Calgary

 

[Danno]

Also is Krown something you can purchase in stores and apply yourself? I can't seem to find any places out West that deal with it at all, the closest one is 10 hours away in Calgary

Found it at Amazon, 6 pack . CT also has it.

 

[Snagglefoot]

Also is Krown something you can purchase in stores and apply yourself? I can't seem to find any places out West that deal with it at all, the closest one is 10 hours away in Calgary.

Krown can be ordered from Amazon.ca in individual spray cans. I do this. It requires yearly touch ups. I see Danno beat me to this.

 

[Nukeman7]

See if you can find this in the fishing/boat supply section of your local WalMart, boating store (e.g. West Marine) or outdoor sporting goods store (Cabelas, Bass Pro Shop). It dries like a wax film (and smells like Crayons), unlike Fluid Film which stays runny.

 

[Rand]

the aftermarket rubbery type and asphalt type are both worse than nothing.

 

[Trav]

Noxudol is the best bar non, 300 for the underbody and 700 for the inside panels. Amazon carries it.

Noxudol 300 500ML Aerosol Can | Spray Undercoating | Noxudol 300

Noxudol 300 500ML Aerosol Can is a rust preventive product free from solvents. Low viscosity binding agents and additives have been mixed with enable application at a low temperature.

www.noxudolusa.com

 

[Rust_Belt_Pete]

Yes. Got it done by a detailer when the truck was brand new.

In that case i would get rid of it asap. Its a membrane a baloon and it cracks the moment you roll out of the garage after the application so all it does is cover rust and promote it by trapping water. Oils creep and spread and self heal.
have a watch

 

[meep]

That doesn’t look worn. That looks clean, like it was never reached.

Aftermarket undercoating can trap moisture when it ages and dries and cracks. If it’s rush free, you might do better hosing it off and hitting it with a few coats of rustoleum, if you aren’t in the rust belt. If rust belt, the oil sprays are always the most regarded here. I live in the south and don’t see northern rust much.

 

[Snagglefoot]

See if you can find this in the fishing/boat supply section of your local WalMart, boating store (e.g. West Marine) or outdoor sporting goods store (Cabelas, Bass Pro Shop). It dries like a wax film (and smells like Crayons), unlike Fluid Film which stays runny.

View attachment 237774

Also available on Amazon. I have 6 cans of it. It did very well in several independent You Tube Tests.

 

[JohnnyG]

IMO, that's not worn, it was never sprayed.

 

[finmile]

I was considering Fluid Film, however I asked them and they advised against it as they said it would penetrate the existing rubber undercoating and separate it from the frame. Not sure if Krown has similar properties to that but I will ask them.

Kind of what you want to do, right?

Definitely this.
See some horror story about rubberized undercoat by Eric O below.

 

[supton]

I live in the south and don’t see northern rust much.

Lucky you. I recall looking at new Chevy trucks and they would have surface rust on the frame—new on the lot.

At times I think “low rust” just means you can still see threads and bolt heads on the bits underneath. At some point everything morphs into one ugly mess.

 

[Trav]

Definitely this.
See some horror story about rubberized undercoat by Eric O below.

That why I use Noxudol, it is not rubberized and really never cures to a hard finish, it remains soft and pliable. Rubberized is a nightmare, I have seen flintstone cars that look perfect underneath until you poke at it.