Undercarriage Rust Prevention: Used ATF, 75W-90, or Marine Grease? (1 Viewer)

[jammingator]

Having just serviced my 2001 LC, I have plenty of options to spray/wipe down the undercarriage. I'm aware of fluid film, etc but this is already bought and paid for. Any thoughts?

I included marine grease because I have part of a tube that I store in a jar and I know some have used it for various types of rust protection.

I'm also considering using Ospho first, as I have some on hand, then applying oil/grease.

 

[mitchjohnson000]

As a person that constantly battles road salt, save your oils for their intended purpose. IMO it's not worth the trouble. Applying various oils to the underside is messy and time consuming. I'd just stick to a gallon of FF and a paint gun. A gallon of FF is $40 and is well worth it.

 

[jammingator]

Thanks mitch - I am considering FF but I understand it to be messy as well? Just really starting to look into this a little harder. Also, I should clarify that these are all used oils and the grease is out of the tube.

 

[abuck99]

Used ATF would work, but any sprayed on petroleum product especially the used stuff would suck environmentally speaking. Everytime it rains, snows etc. your undercarriage gets wet and your dripping that s*** on the ground and it eventually finds its way into the water table. Not optimal.

Check out the non toxic options.

 

[nissanh]

I spray motor oil and gear oil mixture (20% or so gear oil: Gear oil stays for a while) all over the underside. the dust gathered over it makes the surface hydrophobic... I've been doing it for 30+ years now and see no corrosion at all!

 

[Moridinbg]

Spraying your undercarriage with any kind of motor oil is in the same league with coal rolling...

 

[jammingator]

I guess I should feel guilty about driving a 19 year old vehicle which sometimes leaks petroleum based fluids and gets 14 mpg as well?

 

[dogdaysindurham]

I like Amsoil HD Metal Protector and it last a bit longer than FluidFilm. Krown is also popular undercoating option.

 

[Tookie]

Hi, can you get Bilt Hamber products? Dynax S-50 for inside the chassis and Dynax UB for the outer surface

 

[abuck99]

We’re all are driving them-

Not shaming you here, simply offering a more earth friendly suggestion. Do what you want.

 

[RiverRatMatt]

Project Farm tested under coatings recently. Used motor oil (like ATF, probably), did nearly nothing. Good recommendations in the vid. Skip to 14:30 for summary.

 

[hickuptruck]

Really? All this stuff washes off does down the drain and into the ecosystem. That's up there as bad as pouring waste oil down the sewer.

Want to do it right? Take your body off, sand blast, then repaint with an epoxy that will live longer than your LC.

Too much work? Por-15

Got tired of fluid filming every year. FF works, but washes off and is relatively pricey.

 

[Pucker5]

Having just serviced my 2001 LC, I have plenty of options to spray/wipe down the undercarriage. I'm aware of fluid film, etc but this is already bought and paid for. Any thoughts?

I included marine grease because I have part of a tube that I store in a jar and I know some have used it for various types of rust protection.

I'm also considering using Ospho first, as I have some on hand, then applying oil/grease.

I got a thing of ospho from Home Depot and was going to apply it with a wand sprayer. Is the tape off and prepping protocol super gnarly? I’m going to scrape and wire brush first

 

[jammingator]

@Pucker5 I would consider brushing the Ospho on for the most part, then use a squirt bottle where you need. Will greatly conserve material.

Scrape and wire brush first, then apply. If you're going to paint it - let sit for at least 24 hours, then reapply and immediately wash off with water. The reapplication will rewet the product so it can be washed off before painting. I think the directions say wash off with mineral spirits but I have found that there will be a sticky film that only rewetting will cut. This will result in a nice rust conversion ready for paint whenever it's dry. For tough to reach areas where you won't paint you don't really have to do anything after the first application.

 

[dogdaysindurham]

Fluid Film is nice since it's based on Lanolin (the oil sheep and other wool producing animals make), but it does wash off relatively easy as I had to recoat 2-3 times in the winter. It does make rubber swell, but I've never had any issues with it weakening hoses or anything of the short.

Amsoil HD Metal Protector is want I have switched to as it seems to last longer.

For rust converting chemicals, this is a US gov study for it's application in outdoor metalwork preservation (i.e. artwork and what not): https://www.ncptt.nps.gov/wp-content/uploads/metal-paper-88.pdf and more background info here: https://www.ncptt.nps.gov/blog/comparative-study-of-commercially-available-rust-converters/

Rust Reformer seem to perform the best, but I think in the study design they only applied the different agents and didn't add a paint layer on top of the coating that most would normally do in our application.

My truck originally was from Ohio and it's been a PITA dealing with rust fused nuts and bolts. I have been coating bolt and nut threads with Never Seez Marine Grade anti-seize to prevent these issues from recurring.

 

[Pucker5]

I wasn’t planning on painting it. Was going to just go it. I figured opsho discoloration is better than rust brown