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2021 Dodge Challenger GT AWD
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Discussion Starter · #1 ·
I just bought a new challenger, It should be here in 6-8 weeks. I would like it to last at least 20 years, In the rust belt, so some sort of extra layer is required. I'll be doing a decent job keeping it clean, but just washing it isn't going to be good enough.

I've been considering using LizardSkin as an undercoat, I've seen some video's of people doing it to jeeps and trucks, and plenty of people using it on the inside of older restored cars. I haven't seen any video's of people using it on new cars though, which is very concerning. It does provide sound deadening and heat resistance which I've found a very attractive feature. What do you guys think?

I've also been considering using CRC 06026, based on the review of undercoating's ProjectFarm did. It's described as "cosmolene in a can" and seams to perform well.

Any good or bad undercoating stories to talk about? I know to steer far far away from the rubberized coatings, and I know the dealership offered wax coatings are terrible as well. Tar apparently isn't to good either. What do you guys use?
 

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I don't have undercoating on my 2009 SRT and have no rust. I live in NJ and my car is not a daily driver. Because I do not live in the rustbelt, the galvanized metal is sufficient protection for my car.

I have read that 3M rubberized undercoating is the best. However, as with any undercoating, the only way for it to provide ongoing protection, in a salty environment, is to have the service repeated every 3-5 years.

You should also take your car to a touchless car wash periodically to remove salt residue from the body.
 

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When I researched undercoatings for my 2018 AWD GT (since it is a year-round daily driver in Pennsylvania), it seems that the consensus was not to use an undercoating at all... It's hard to even find places that do it anymore. People kept telling me that the coatings end up causing more rust than the stop because water (and condensation) gets trapped between the coating and the metal, making it rust even faster. When combined with more rust-resistant metals (stainless steer, "e-coatings", etc), people say that the undercoatings just aren't needed anymore (which is probably why it's hard to find people that do it anymore).

Like mentioned above, I'll just take the car to a touchless car wash with undercarriage spray and get the crap off as fast as possible that way.

Besides, it seems that the rear quarter panels are going to rust from the inside out before we have to worry about the rest of the car rusting (unfortunately). Apparently, due to the spray-in foam they use in the panels, water gets in and absorbed by the foam, which then keeps the moisture in contact with the inside of the quarter panels, causing them ro rust from the inside out - regardless of how well you take care of the paint on the outside. You'll see this starting as "paint bubbling" in front of the rear wheels. Eventually, it will rust all of the way through, from the inside out. Many examples of this on the forum - some even happened before the 5-year rust-through warranty ran out. Seems like the issues usually occur between 5 and 7 years though.

Can't figure out why it effects some, but not others. Climate doesn't even seem to play a huge part (I've heard of people in places where in never snows having the problem). Possibly just caused by rain and maybe even car washes over time?

Normally, I keep my cars for a very long time, but it doesn't seem like that is a good plan for these Challengers if they are daily-drivers.

People will say "that happens on all cars in the rust belt!" - but it's not true - I had a 2005 Buick LaCrosse that I traded in for my Challenger - no rust issues. I also still have a 2012 Impala - absolutely no rust issues. It's all because of that damn spray-in foam that they use.

However - all of that being said - I really have no idea what "percentage" of CHallengers have this problem. Sometimes, issues can be blown out of proportion on forums.
 

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2020 Dodge Challenger Hellraisin Scat Pack
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Nothing.

For my cars (Porsche Boxster, VW Golf TDi) I bought and drove year 'round in all kinds of weather when I lived in the KC MO area every once in a while I'd visit a DIY car wash that in order to remain open in the winter offered heated water. I'd select the rinse setting and just rinse the car down. The salt is of course water soluble and the water removes it. I'd treat not only the easy to reach painted surfaces but get down and spray the underside of car to remove any ice/slush or just salt residue.

I'd rinse the A/C condenser and radiator.

As an aside I did not use the drive through car washes. While there were loads of these and every one received considerable use the rinse water has a wax in it.

Really just treat the car to an occasional "rinse". No soaping. No brush. Just a thorough rinse followed by a no spot rinse. As is the case at any other time the car is washed be sure you drive the car after and enough to give you plenty of time to use the brakes hard enough to get them hot to thoroughly dry the brake hardware including the "buried" parking brake hardware in the rear wheel hubs.

When nice weather returned then at home I'd run a hose from the laundry room sink faucet to the driveway and treat the cars to a thorough washing with car finish/wax friendly soap and lots of pretty warm water.

Couple of other things: I avoided gravel roads. The rocks can chip the paint underneath and this can lead to rust getting a foot hold. I can only recall one time I ended up on a gravel road. Thankfully it was a short stretch and I was able to drive slow enough no rocks hit the underside of the car.

Related to this I was very careful to when I jacked up the car to avoid marring the finish under the car. Both cars had every inche of sheet metal under the car painted. This included the areas which were the factory sanctioned lift points. At the dealer the service bay lifts all had rubber pads which prevented any damage to the painted surfaces. At home I used a hocky puck on the floor jack lifting plate so the puck only contacted the metal of the car's lifting point.

But I really tried to avoid situations where I needed to use the floor jack. For oil/filter services I drove the cars on ramps. In hindsight I should have bought a portable hydraulic lift that I could use to lift either car by its tires or if I wanted to be able to remove the wheels/tires for a brake job to lift the car by its factory lift points with of course lifting pads on the hydraulic lift with something to prevent any damage to the painted surfaces.
 

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Oil based, NOT rubberized, will trap water and rust inside and rot from the inside out
It is important especially when the weather warms up all salt residue is rinsed away and no water remains "trapped" anywhere. It is in warm weather that the salt is more active. If any trapped by any under coating, and this includes rubberized, it can only remain to work its damage.

My Porsche Boxster came with a cosmoline like material sprayed onto the various "bare metal" hardware under the car: Engine block, oil pan, suspension hardware, all bare metal steel and aluminum.

My Cayman S likewise. I don't have pics of this from the Boxster but I snapped pics of it on my Cayman S:

Metal Brass Machine Steel Bronze


But none was sprayed on any of the painted metal surfaces under the car.

No undercoating is best.
 

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I have used AMSOIL HEAVY DUTY METAL PROTECTOR on my 08 Chebby Pic Up (Daily Driver) and my 04 Furd Explorer (Winter Beater) and I have Zero Rust. This stuff works and won’t wash off.
Fuggabout rubberized coating that trap water and clog drains.
Fluid Film (Lanolin Based) is what I use on my snow equipment and it has worked good.

BTW! The Amsoil HD Metal Protectant is NOT available for sale in Canada so it must be good.
 

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Undercoated cars when optional from the factory definitely lasted longer than those that weren't.
Our recently totaled plum 2010 RT was rotting from the inside out just as described above at about five years old. A daily driver but waxed and hand washed often. At the time of the accident 6 weeks ago the rust took dollars off of the valuation of the car ($1600.00).

Our new Challenger will get some kind of undercoating because I gotta do more to help the car not rot away.
 

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Under the right conditions, these cars rot out from the inside out.

Call it a MOPAR retro touch or whatever, undercoating won't stop that on a daily driver.
 

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Living in Northern Ontario with salty roads 6 months a year you definitely need to rustproof a car if you want it to last more than 5 years. Widely accepted best rustproofing are the ones that are applied yearly such as Krown, Corrosion Free and Rust Check. These are all based on thin oils that seep into all the small crevices where rust usually starts. These products are very affective at preventing rust, but definitely have to be done annually.
 

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2016 Dodge Challenger R/T Plus
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When I researched undercoatings for my 2018 AWD GT (since it is a year-round daily driver in Pennsylvania), it seems that the consensus was not to use an undercoating at all... It's hard to even find places that do it anymore. People kept telling me that the coatings end up causing more rust than the stop because water (and condensation) gets trapped between the coating and the metal, making it rust even faster. When combined with more rust-resistant metals (stainless steer, "e-coatings", etc), people say that the undercoatings just aren't needed anymore (which is probably why it's hard to find people that do it anymore).

Like mentioned above, I'll just take the car to a touchless car wash with undercarriage spray and get the crap off as fast as possible that way.

Besides, it seems that the rear quarter panels are going to rust from the inside out before we have to worry about the rest of the car rusting (unfortunately). Apparently, due to the spray-in foam they use in the panels, water gets in and absorbed by the foam, which then keeps the moisture in contact with the inside of the quarter panels, causing them ro rust from the inside out - regardless of how well you take care of the paint on the outside. You'll see this starting as "paint bubbling" in front of the rear wheels. Eventually, it will rust all of the way through, from the inside out. Many examples of this on the forum - some even happened before the 5-year rust-through warranty ran out. Seems like the issues usually occur between 5 and 7 years though.

Can't figure out why it effects some, but not others. Climate doesn't even seem to play a huge part (I've heard of people in places where in never snows having the problem). Possibly just caused by rain and maybe even car washes over time?

Normally, I keep my cars for a very long time, but it doesn't seem like that is a good plan for these Challengers if they are daily-drivers.

People will say "that happens on all cars in the rust belt!" - but it's not true - I had a 2005 Buick LaCrosse that I traded in for my Challenger - no rust issues. I also still have a 2012 Impala - absolutely no rust issues. It's all because of that damn spray-in foam that they use.

However - all of that being said - I really have no idea what "percentage" of CHallengers have this problem. Sometimes, issues can be blown out of proportion on forums.
That rusting from the inside out is exactly what happened to my sebring convertible that I just finally had hauled off to the great car lot in the sky.... I assume it was the exact same problem. I've recently also heard the same thing about spray in bed liners on trucks causing more rust than not having a bed liner at all.
 

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The thing that is nice about the AMSOIL HD metal protectant is that you can use the "straw" to get into frame rails, door cavities and all the nooks & crannies. PLUS it doesn’t run or drip when it gets hot like some other products....... It goes on easy and looks like the "amber" coating in post #6.
I used 3 cans on my Challenger and it was enough to do the doors and body panels

TIP! You can also use the "log flexible tubes" to really get into long areas.
 

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2021 Dodge Challenger GT AWD
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Discussion Starter · #14 ·
I appreciate all the replies guys! Looks like what I'm seeing is they are prone to rotting from the inside out due to foam absorbing water. Especially in the rear quarterpanels, and it's undecided whether the 2015 fix was legitimate. How about if I presoak that foam with an absolute buttload of oil or oil based undercoating? Like spray a couple cans in there, then do the silicon/rtv fix? Anything bad you guys could see as a result of that? I'm just really worried about ruining my brand new car while trying to prevent it from being ruined. And as far as undercoating goes sounds like it's a mixed bag, oil based and yearly seams to be the preferred way, is there anything these shops do that I couldn't do better using my buddy's lift? I'm sure I can do a more detailed job than some rando that doesn't care about my car and has a time limit would.
 

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Discussion Starter · #16 ·
Would the cavity wax soak into the foam? Or just dry on the surface? I'll be adding sound deadening so a bunch of the inner rust prevention will have to wait until that's on (doors ect)
 

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Would the cavity wax soak into the foam? Or just dry on the surface? I'll be adding sound deadening so a bunch of the inner rust prevention will have to wait until that's on (doors ect)
Just take the foam out and be done with it, the point of the wax is it melts into the seams where paint can not get into.....
 
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