RC Fan Posted September 4, 2018 Share Posted September 4, 2018 Hello! We have a 2018 Expedition which we will hopefully have for 7 or 8 years. For those of us in northern climes where our vehicles are subject to road salt, what is the overall opinion on undercoating for rust prevention? I know some of the body panels are aluminum, which hopefully is less susceptible to rust, but I assume the undercarriage, etc, is steel. Thanks in advance for your assistance! Quote Link to comment Share on other sites More sharing options...
bbf2530 Posted September 5, 2018 Share Posted September 5, 2018 (edited) Hello! We have a 2018 Expedition which we will hopefully have for 7 or 8 years. For those of us in northern climes where our vehicles are subject to road salt, what is the overall opinion on undercoating for rust prevention? I know some of the body panels are aluminum, which hopefully is less susceptible to rust, but I assume the undercarriage, etc, is steel. Thanks in advance for your assistance! Hi RC Fan. Congratulations on your new Expedition! Personal/educated opinion here: You do not need to undercoat it. Your Expedition will last far longer than 7-8 years without it. Additionally, undercoating sometimes, does more damage than good in the long run, giving moisture more places to hide out. And it will not add more value to your truck at selling time than it cost. It is simply an additional Dealer markup money maker. Good luck with whatever you decide to do. Edited September 5, 2018 by bbf2530 Quote Link to comment Share on other sites More sharing options...
Rich B. Posted September 6, 2018 Share Posted September 6, 2018 (edited) Many are against it and I've driven cars through winters- with and without undercoat. I like it myself if applied right. In ME cars can rust from the outside in or opposite. Aluminum is subjective to corrosion and winter will certainly aid in creating bubbles in paint from 2 dissimilar metals in contact. To be blunt, the underneath primer only on my '13 Boss302 just plain sucks. Do not drive it at all in winter. Undercoating also serves as sound deadner and sand blasting protection in under areas. Could actually do the underneath with the aerosols, only problem is getting the tough areas if not on lift. Spraying inside fenders, doors, sills, etc would be another process. Be careful to keep all drain holes open with any of that. Edited September 6, 2018 by Rich B. Quote Link to comment Share on other sites More sharing options...
theoldwizard Posted September 7, 2018 Share Posted September 7, 2018 (edited) I am not a fan of "undercoating", at least like it was done in the "old days". All of the warranties required that you get and annual inspection and "touch ups", at your expense ! The Expedition now has all aluminum body panels so there is no issue there. The thing I hear most people complain about in older (>10 tears) "rust belt" cars is brake line failure. The DIY approach is simple. Once a year take your car to the quarter and wash the underside. Once it is dry, crawl underneath and spray Fluid Film on the brake and fuel lines, especially on the fitting. If you want to help your mechanic, at the same time spray all of the nuts and bolts that hold suspension and brake components. Last, remove your wheel and spray the center of the brake rotors and the back of the wheel where the 2 mate. If you want to go a bit further, spray all hinges (hood, doors, tailgate and rear window. A little spritz arounf the rear wiper hub is a good idea. Edited September 7, 2018 by theoldwizard Quote Link to comment Share on other sites More sharing options...
RC Fan Posted September 7, 2018 Author Share Posted September 7, 2018 Thanks for all the replies! I do appreciate the info! Quote Link to comment Share on other sites More sharing options...
GordonZoo Posted September 21, 2018 Share Posted September 21, 2018 I do want to do some type of rust prevention. I lost a F-150 and Dodge Ram in Mass due to rust and I don't want a $90-K vehicle to last just 5 years. I did my 2018 Rubicon and 2016 Ram with Wax-Oil and am happy with it so I'm talking myself into doing it again. It's not cheep at $850. It's a one time application underneath but yearly in the panels. I'm really just concerned with the underneath though. Some have stated it may plug up drain lines but the only drain I'm aware of is the AC. I'm pretty confident they do not blindly spray this stuff as there is a 2 hr prep to cover sensitive areas and a 2 hr spray. Krown is not offer around us or I would do that even though it's a yearly application at $150. Quote Link to comment Share on other sites More sharing options...
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