Cosmoline Treatment

My 2023 TRD Sport now has about 200 miles on it. It is approaching road salt season here in Michigan and I have been reading threads here about using Cosmoline for rustproofing the undercarriage and I think that is something that I want to do. Are there areas that you want to avoid spraying the Cosmoline on? Het shields, muffler, exhaust, oil pan, transmission, brakes, etc. Once done while new I am thinking I can do a lighter application every couple of years. Is that right? I was crawling around underneath the thing while installing some running boards and have never owned a vehicle with as so much clearance....looks like it would be very easy to do this without jacking it up. I understand that the inside of the frame is already treated at the factory so I shouldn't have to worry about getting a long nozzle to reach those areas. Any application advice appreciated....

 

Yea avoid exhaust components, manifolds, etc. Remove the spare tire and skid plates for better access. Also the rubber shields up front need to be removed for better access. You can hit the backing plates to starve off the corrosion as well.

I do a couple light coats on everything I see fit. You will only need to lightly touch up areas here and there over the years. Just keep and eye on it.

 

Thanks Adam...hadn't considered the spare tire or taking the skid plate off.

 

Adam knows his stuff

Avoid spraying anything directly that gets hot. Overspray will just cook off. I would make sure to spray the boxed sections the best you can and poke the straw nozzle into the holes along the boxed section. That's where moisture and salt really like to get trapped and fester. My Tacos frame rusted out in the boxed frame section where the transmission support attached...

 

Spray it, cosmo is good
After it cures soak it with fluid film too

 

Welcome to the forum

Good plan on the Cosmoline, it is an excellent product that lasts well especially when applied to a nice new clean surface. In the future an annual inspection/touch up is a good idea.

You absolutely do need to worry about the box sections - they are a favorite area for dirt/salt/mud/water to sit and rust to grow. Rust is the #1 enemy of these trucks, do your very best to coat every square inch of the frame and under body.

Obviously keep the product off the brakes & exhaust.

 

It's fine to do a couple coats on those brake backing plates, but stay away from the exhaust and heat shields. Avoid spraying anything plastic or rubber although I was told the cosmoline is safe on it. At one time you could buy these longer extension wands to fit a can of rp-342 to get inside those boxed frame sections, but I haven't seen them advertised on eBay again....I bought one at the time, and it worked pretty good. Make sure you apply 2 good coats, removing everything thats in the way of any steel parts. That said I've only needed to do very minor touchups in over 3 years since I did my truck.

 

I'd be careful mixing the 2. Imo, best to stick with one or the other.

 

I did spray it on elec components and wires 3 years ago, zero issues in fact it may have turned off rodents.
Yeah remove the spare and go to town. I suggest a full disposable coverall, goggles and gloves.
Put a light coat of vasolene on your face or exposed areas for easier wash up.

You chose the best, cosmolene, dont add any crap like FF you will just be wasting money as that junk washes off.

 

I use Woolwax, myself. It's like Fluid Film, but a bit thicker. The benefit is that you can wash it off with effort if you really wanted to, but also it "creeps" into areas that you may otherwise miss with something like cosmoline. I usually spray about 5 or 6 cans around November every year. You're also right in that you won't need to jack it up or anything like that. It would make things a touch easier if you have a lift, but most people (including myself) have no access to one.

 

I vote for rp 342 over fluid film or wool wax. I coated everything on my new truck with cosmoline. I used to do fluid film on my old truck but I found slush and salt spray in winter will remove fluid film and start rusting, after 6 years it was starting to rust. Cosmoline seems alot tougher.

 

Doesn't wash off, except on areas that may impact snow, ice, etc. Even taking the truck through a car wash with an under-body flush doesn't take it off. I've been using lanolin products on my truck for six years, and I only need to do touch ups every fall, not full applications. The only downside of the stuff is that it's really messy when you need to do repairs, but I'd rather deal with dirty hands than rusted bolts.

 

Rp-342 cosmoline is so thin when sprayed on, it actually creeps into places as good or better than fluid flim. I haven't had any rodent issues yet, but spraying the cosmoline on wiring sounds like a win if it does deter rodents from chewing wires.
You want to pull the spare, and rear bumper caps to spray in those areas real good too. I even removed my engines skid plate, and chin spoiler to cover a mess of stuff under there, after finding where road salt, and sand can buildup. Job takes at least 6 cans+ for 2 coats.
I use to do my tundra with fluid flim. Found cosmoline far better. I use to hate doing this job every fall only to see fluid flim all wash away by spring, then see surface rust beginning. With cosmoline it's like one, and done....at least 3 years so far.

 

FYI, I did get some over spray on the muffler/tailpipe area. It burned off but smelled just like burning brakes.

 

Cosmoline is petrol based, it can cause a fire if you get enough of it on a hot exhaust.

 

Fluid film does wash off. I could spray it off with my pressure washer if I wasn't carefull. It's not a bad product but the fact that you constantly have to reapply is annoying and expensive. Cosmoline is better and it creeps just like fluid film.

 

You can, but it's not super easy. It's one of the reasons I prefer Woolwax. I liked that I can wash it off if I need to, but it's thicker than FF so it doesn't come off as easily.

 

Brainwashed

 

Any of those lanolin rust inhibitors were found to be only temporary on my tundra with all the wet salty winters we have here. They don't even hold up well on my mower deck vs cosmoline. Imo, your wasting time, and money on stuff like ff.

 

Whoever gave you that 'understanding' was incorrect. It's one of the absolute worst places for rust to begin!

If skip treating that you've only done about 1/3 the job.