Underbody rust inhibitor treatment recommendations.

[2021 LC200]

Cosmoline RP342 is a good choice. It is like fluid film or woolwax, is "dry to touch" and does not come off. Just be careful when you apply as it will stick on everything.

Look from about 8:30 to 9:00 min. HP washer does not remove RP342

 

[biff44]

I just had mine done here in Massachsetts.
they woolwaxed (lanolin based product) on every exposed part underneath, and fogged the interior panels with a New Hampshire Oils product (that supposedly creeps into cracks better).

the only drawback, the woolwax will stay semi-liquid for some time, so expect to be getting some on your hands for the next month or so.

 

[TheGrrrrr]

Good comparison and review.

 

[yonah]

I just had mine done here in Massachsetts they woolwaxed (lanolin based product) on every exposed part underneath, and fogged the interior panels with a New Hampshire Oils product (that supposedly creeps into cracks better).

the only drawback, the woolwax will stay semi-liquid for some time, so expect to be getting some on your hands for the next month or so.

I’d be interested in your Woolwax feedback after this winter season. Mainly any corrosion in and around the welds on the frame - those welds seem to be the weak point and the first place where rust forms (after the KDSS components, of course).

You’re in the trenches compared to the rest of us - MA’s winter roads are brutal from what I’ve been told by coworkers and seen on other forums/YouTube. Best of luck.

I’m down in VA and from the looks of it, the road salt here is not that bad relative to the NE and Midwest. From what I’ve seen and learned the through observation/conversation, the SUVs/trucks that are heavily corroded in these parts are simply neglected and not washed during the winter season, so I think a lanolin application each fall should be more than enough protection.

 

[mdh384]

RP-342 lasts longer than the classic fluid film, however it does get worn away after a few trips through a car wash with high pressure under carriage sprayers. You’ve also got to be okay with the smell of cosmoline for a while after application. If you subscribe to the idea that at least yearly visual inspections of the underside of your vehicle are a good thing, RP-342 is a workable protectant.

 

[biff44]

I’d be interested in your Woolwax feedback after this winter season. Mainly any corrosion in and around the welds on the frame - those welds seem to be the weak point and the first place where rust forms (after the KDSS components, of course).

You’re in the trenches compared to the rest of us - MA’s winter roads are brutal from what I’ve been told by coworkers and seen on the other forums/YouTube. Best of luck.

I’m down in VA and from the looks of it, the road salt here is not that bad relative to the NE and Midwest. From what I’ve seen and learned the through observation/conversation, the SUVs/trucks that are heavily corroded in these parts are simply neglected and not washed during the winter season, so I think a lanolin application each fall should be more than enough protection.

Since MA drivers pretty much all drive like drunk teenagers, they have to heavily salt the roads here to keep them all from sliding off in the snow. So we have to deal with that eating away at the steel!

 

[thebc]

I just had mine done here in Massachsetts.
they woolwaxed (lanolin based product) on every exposed part underneath, and fogged the interior panels with a New Hampshire Oils product (that supposedly creeps into cracks better).

the only drawback, the woolwax will stay semi-liquid for some time, so expect to be getting some on your hands for the next month or so.

Interested to hear who you used and how your experience was. Truck is currently fluid filmed when I got it but will be looking for a good local shop to maintain her going forward.

 

[yonah]

Interested to hear who you used and how your experience was. Truck is currently fluid filmed when I got it but will be looking for a good local shop to maintain her going forward.

What’s your take on the FF treatment? Is any rust present despite the treatment? I’m assuming your 200 is a year or two old.

 

[Mohican21]

I got my Heritage this past March. I immediately got it home and applied CRC marine corrosion inhibitor. I got around to doing my winter coat last week and the only two spots that really needed to be done again were the lca's and stock skids. Zero rust anywhere. I went ahead and degreased the undercarriage, rinsed, then dried for a day. Did something a little different this time. CRC marine for the frame, Blaster surface shield on those high up places and the spare tire mount. Noxudol for all the cracks and crevices. I'm very confident for the winter and looking forward to the outcome!

 

[yonah]

Here’s a recent 5-year review of Fluid Film that I found. Not a great deal of time is spent under the truck, but the undercarriage and body panels appear to be in great shape. It’s a Dodge too, so that’s saying something.

 

[vmfire]

Waxoyl Hard wax undercoating and 120 cavity spray. I use it on $1m+ fire trucks as well. Works great. Displaces water and you don’t have to respect each year.

 

[jivewalker]

Today or tomorrow I will be applying fluid film for the first time. Any tips on where not to spray? I'm assuming I should drop all of the skids? I'm not going OCD on this, just don't have the time or energy. I have 4 cans and want to do the best with what I have. Tips or advice appreciated before I get under there. Thanks!

 

[linuxgod]

Today or tomorrow I will be applying fluid film for the first time. Any tips on where not to spray? I'm assuming I should drop all of the skids? I'm not going OCD on this, just don't have the time or energy. I have 4 cans and want to do the best with what I have. Tips or advice appreciated before I get under there. Thanks!

Avoid the exhaust. No need to spray any plastic. You can spray the backing plates for the brakes but avoid the discs and pads. I've not had any issues with spraying anything rubber.

Get the frame (don't forget the top side where feasible, bolts, nuts, suspension, etc. Spray inside the frame holes wherever possible.

 

[jivewalker]

Avoid the exhaust. No need to spray any plastic. You can spray the backing plates for the brakes but avoid the discs and pads. I've not had any issues with spraying anything rubber.

Get the frame (don't forget the top side where feasible, bolts, nuts, suspension, etc. Spray inside the frame holes wherever possible.

Do you drop all the skids? Will it work on the KDSS items instead of marine grease?

 

[linuxgod]

Do you drop all the skids? Will it work on the KDSS items instead of marine grease?

I don't, I just hit what I can reach. My intention isn't to completely prevent all rust though, but just to do my best to hold it off with the $50 and 1 hour I'm willing to invest once per year.

I'm sure you can use FF on the KDSS screw heads but trust me when I say that marine grease will last far longer. Just a dab on your finger and slather it on and around the head and it'll still be there next fall, even after multiple water crossings.

 

[yonah]

Today or tomorrow I will be applying fluid film for the first time. Any tips on where not to spray? I'm assuming I should drop all of the skids? I'm not going OCD on this, just don't have the time or energy. I have 4 cans and want to do the best with what I have. Tips or advice appreciated before I get under there. Thanks!

Four cans is a minimalist approach, which is totally fine given your intent.

From what I’ve seen, when compared to domestic vehicles, as a platform 200s are actually very resilient to corrosion, but there are some problem areas. You just have to strategically target the rust prone locations. With only four cans, I would hit the below:

- Frame welds
- KDSS Valves (followed up with marine grease or a high viscosity lanolin product)
- KDSS linkage in front/rear
- Rear axle housing, shock mounts, and track bar mount
- All exposed hardware, specifically the fasteners on the front suspension
- Crossmember under the transmission/transfer case
- Metal tubing/skid under around transfer case
- Transmission pan bolts - especially the ones with exposed threads
- Spare tire lowering mechanism

Four cans should be enough to lightly coat all of these areas with a little left over for future touch-ups during the winter season.

I have paid attention to a lot of rust-related photos on here and the various 200-specific Facebook groups - this informed my recommendations. In my opinion, I would consider the above list to be the most rust prone areas on the 200. There may be some more spots that I missed and hopefully others can chime in to add.

I'm sure you can use FF on the KDSS screw heads but trust me when I say that marine grease will last far longer. Just a dab on your finger and slather it on and around the head and it'll still be there next fall, even after multiple water crossings.

Agreed. Marine grease is the lasting solution.

 

[linuxgod]

Four cans is a minimalist approach, which is totally fine given your intent.

From what I’ve seen, when compared to domestic vehicles, as a platform 200s are actually very resilient to corrosion, but there are some problem areas. You just have to strategically target the rust prone locations. With only four cans, I would hit the below:

- Frame welds
- KDSS Valves (followed up with marine grease or a high viscosity lanolin product)
- KDSS linkage in front/rear
- Rear axle housing, shock mounts, and track bar mount
- All exposed hardware, specifically the fasteners on the front suspension
- Crossmember under the transmission/transfer case
- Metal tubing/skid under around transfer case
- Transmission pan bolts - especially the ones with exposed threads
- Spare tire lowering mechanism

Four cans should be enough to lightly coat all of these areas with a little left over for future touch-ups during the winter season.

I have paid attention to a lot of rust-related photos on here and the various 200-specific Facebook groups - this informed my recommendations. In my opinion, I would consider the above list to be the most rust prone areas on the 200. There may be some more spots that I missed and hopefully others can chime in to add.



Agreed. Marine grease is the lasting solution.

I recommend hitting the brake dust shields as best you can (without getting FF on the rotors). You won't be able to hit the inside near the discs but at least you can try to stop rust on the outer exposed part.

I buy 6 cans to do everything you've listed and more. I really try to hit the front area well since with an aftermarket bumper I get a lot of direct road spray. Control arms, frame, shocks, etc. Coverage is better at the start of each can then at the end, so I typically try to hit the frame and bigger sections at the start of a can and then use the last 1/3 or so to go after bolts or other areas where wide coverage isn't critical. The big gallon cans and the spray gun would likely work better but for the once a year I do it I can't bring myself to bother.

 

[biff44]

i would get some cans of compressed air and blow out the weep holes underneath the four doors, then try to "fog" the insides of the cavities.

 

[jivewalker]

I hit everything that looked like it should be coated. Didn't have marine grease right now, so caked the Kdss with the spray. Definitely got some on the exhaust. There's no chance that stuff is going to flame up is there?

 

[04UZJ100]

I hit everything that looked like it should be coated. Didn't have marine grease right now, so caked the Kdss with the spray. Definitely got some on the exhaust. There's no chance that stuff is going to flame up is there?
View attachment 2872338

No it won’t.