Is Cosmoline closest to GM frame wax?

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Not sure if its the same. But the product you linked to reads like asphalt sealer. Its mostly, 99%, just asphalt and solvent, thats it.
 
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New York
If you want exactly what GM is recommending you use, have you ever looked at the products they mentioned in their frame rust TSB? They say the rust should be treated using "Lloyd's Kryptonite Metal Treatment (P/N 36502) Life Long Rust Protection", then followed up with the black frame wax "Daubert Nox-Rust® P/N X-121B". If you're looking for a direct replacement of the black frame wax, the Nox-Rust is the way to go according to GM.
 

LeakySeals

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Originally Posted by Jimzz
Not sure if its the same. But the product you linked to reads like asphalt sealer. Its mostly, 99%, just asphalt and solvent, thats it.
That must be the black RP-344. Its definitely not the thick version of Cosmoline (RP-342).
 

LeakySeals

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Originally Posted by NoNameJoe
If you want exactly what GM is recommending you use, have you ever looked at the products they mentioned in their frame rust TSB? They say the rust should be treated using "Lloyd's Kryptonite Metal Treatment (P/N 36502) Life Long Rust Protection", then followed up with the black frame wax "Daubert Nox-Rust® P/N X-121B". If you're looking for a direct replacement of the black frame wax, the Nox-Rust is the way to go according to GM.
Thank you!!! I purchased 3 cans of X-121B for the frame touch up, 3 cans of the RP-342 amber wax for the rest of the undercarriage. Now to figure out what to do with 8 cans of Fluid Film..
 

LeakySeals

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Update. the X-121B is nice to get the black color. But as far as ease of use, how tacky the wax remains, I think the RP-342 is the better choice. It wicks into the tiniest places then sets up nice. Beads up, repels water, no soot. Connector friendly. i tried one that was coated and it wasn't stuck. Removing Fluid Film chips, oil, and soot is still giving me fits trying to put this on..

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Is the Cosmoline that much better than Fluid Film? Looking to protect a Chevy Tahoe with a goodly portion of the factory wax long gone and surface rust well established but not BAD. Reading the Cosmoline website, the 342 DEFINITELY sounds like the better option with the 121 being more of a rubberized undercoat type product?
 

LeakySeals

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The oil in FF softens and degrades the GM frame coatings. If you contact FF they will tell you its not recommended for GM trucks with the factory wax coating (if thats actually what it is). So if you have any left, don't use. Having used both, I think RP-342 is far superior to FF for undercarraige rust protection. The RP-342 is a special cosmoline wax. Meets govt specs. Thicker. tougher. Harder. But still self heals. It does cost more, but I have no doubt this stuff will last 5x longer than FF. Because its not a fluid. Its a wax. The nox-121b is a match to whatever that original coating was. its not as hard, stays tacky. Maybe thats the fluid film still haunting me. However the left over oil from FF has no effect on the RP-342. I still covers nicely, pretty hard. Only slightly tacky.
 
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I've been using Fluid Film for quite a few years and my 2002 vehicle has NO rust. I do live in the rust-belt. I have never used Cosmoline, but it looks interesting. I just ordered a case of RP-342 (12 aerosol cans). It was more expensive than other cosmoline manufacturers, but this RP-342 is Military Grade. I think both Fluid Film and Cosmoline have a place for undercoating. Fluid Film - Good for existing rust where it will penetrate thru the rust to base metal Cosmoline - Individual parts being replaced, inside engine compartment, wheel wells etc Can't have too many tools in the tool box.
 
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I've had zero issues using fluid film over GM factory undercoating wax. I think it does "soften" it but keep in mind, the wax undercoating on GM trucks becomes brittle, dry and cracks within months of ownership. The fluid film - as long as you're reasonably liberal with it - keeps it pliable. But I will say I have used the Cosmoline stuff before and I like it better than fluid film...it's stronger, it doesn't wash away anywhere near as easily. Now I kind of wish I went that route instead of buying a five gallon bucket of the FF.
 
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Originally Posted by LeakySeals
I just ordered a can - my part of California doesn't have as much air quality restrictions as SoCal, shipping kinda killed me but still. I need to carry this out on a friend's car - Subaru won't do it since it's a CA car but Tahoe sees the same issues as the rust belt. Cosmoline would be even better than Fluid Film for this. https://static.nhtsa.gov/odi/rcl/2014/RCMN-14V311-4153.pdf
 
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Has anybody here used Cosmoline RP-342 and Amsoil HD Metal Protector? How do they compare in terms of thickness, drying time, etc? The Amsoil MP seems rather thin and leaves only a very thin film after drying.
 
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I used the Amsoil HDMP on my F150 the first winter after buying it used (with very low miles) a number of years back. Truck was basically rust-free before winter. After winter it had developed some very light surface rusting along the edges of the sheet metal in many places. I switched from HDMP to Fluid Film and have had excellent results- but it does get reapplied yearly now.
 

LeakySeals

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Update: Its been approx 10 months since the first application of RP-342. Including one winter. The rear wheel wells and everything in the area are the trouble spot for rust on this truck. Nothing rinses off under there. As stated before, my prior Fluid Film habit hampered the first application. Lots of oily soot, sand, and grit flaking off in chips exposing areas of rust underneath. Would appear its still an issue. One area that still has minor FF flaking off. Still has soot clinging to the body. Same for the other side. [Linked Image] [Linked Image] For the most part, the RP-342 held up pretty well. Used a pressure sprayer on low to get anything loose and reapplied. Decided to leave the rusted surface metal bare and coated it with nothing but RP-342. See what happens next year. [Linked Image] [Linked Image] In summary there were a few spots that chipped off and some minor rust bled through, and thats probably my doing not getting all the FF off. But this time around was fast. Other than these areas the frame and undercarriage is clean. I didn't reapply everywhere. The rear still holding up from the original application. Going to leave it alone. [Linked Image]
 

JHZR2

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Originally Posted by LeakySeals
Update: Its been approx 10 months since the first application of RP-342. Including one winter. The rear wheel wells and everything in the area are the trouble spot for rust on this truck. Nothing rinses off under there. As stated before, my prior Fluid Film habit hampered the first application. Lots of oily soot, sand, and grit flaking off in chips exposing areas of rust underneath. Would appear its still an issue. One area that still has minor FF flaking off. Still has soot clinging to the body. Same for the other side. ] For the most part, the RP-342 held up pretty well. Used a pressure sprayer on low to get anything loose and reapplied. Decided to leave the rusted surface metal bare and coated it with nothing but RP-342. See what happens next year. In summary there were a few spots that chipped off and some minor rust bled through, and thats probably my doing not getting all the FF off. But this time around was fast. Other than these areas the frame and undercarriage is clean. I didn't reapply everywhere. The rear still holding up from the original application. Going to leave it alone.
My understanding is that FF and GM frame wax do not mix - FF ruins the wax. FF is also prone to wash off quite easily. I use it on spots where wash is not an issue and it stays indefinitely, but I'm surprised that it with dirt and soot remained and got in your way. The guys that apply waxoyl recommend a pressure wash of the undercarriage. Not a bad idea. Now that you have a year on the cosmoline, is it soft and pliable/self-healing, or has it set up harder?
 

LeakySeals

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It's the same. Harder when it's cold. On a warm day it's softer but doesn't flake off or anything like that. Definitely wear gloves it's tough to get off your hands. I can smell it a bit on warm days. And the best part is the surface stays clean. No soot. Just bought another case and a extension nozzle for the inside of the frame. I also plan to put it in the snowblower chute. I'm hoping it will make the surface slippery like fluid film but without the oil. [Linked Image]
 
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