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2020 Kia needs an undercoat—true or false?

Just bought 2020 Kia Forte in Buffalo, NY, do I need to undercoat it? Dealer says yes

I wouldn’t

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NO!

Dealer add-on profit.

Tester

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Concur, not needed. It could make any rust problem that might develop worse in fact, by trapping water/salt against the under-side of the car.

Here’s some pretty good practical ideas how to keep rust to a minimum

Get money saved and spend a small fraction of it to regularly wash the car (including underbody!) on a good carwash during the “salty bath season”, you will get much better rust protection from this than from “undercoating”

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The big thing you do not know is if it was driven on salted roads, how well they clean it before they put the sealer on, in which case the sealer just traps in things that from my recollection can turn out worse than no sealer at all, hope others can confirm or repute my recollection.

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False but in Buffalo, put the money into winter tires and a set of chains.

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It’s a 2020 how much could it have been driven, anywhere?

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Most people forget to neutralize the salt before cleaning the underbody. I fill up my garden sprayer with a solution of baking soda and water and spray it everywhere where road salt has accumulated. I wait 10 minutes then power wash the underbody.

No. Your vehicle does not need it.
The dealer needs you to do it so they can get more of your money into their pockets.

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Just trying to picture power washing the underbody unless on a lift. I’ve got a pressure washer and the thing will about knock you off a ladder when you pull the trigger. Even laying under the car would make it hard to wash underneath.

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Doesn’t baking soda contain salt?

My question about the baking soda - salt isn’t acidic, so why the baking soda?

5 miles on a wet salted road can pretty well coat everything imhop.

Road salt is typically sodium chloride, and when mixed with water forms an acidic solution. Spraying with a baking soda solution will neutralize the acid. If it overcompensates, that’s not a problem for steel, though it would be for bare aluminum. And yes, baking soda is a salt, but an alkaline salt.

Will the salt harm the paint if it is not cleaned off before the undercoating is applied?

Maybe I lept to an incorrect conclusion, my thought was undercoat was for the frame.

Not if it’s just NaCl: " The pH of a sodium chloride solution remains ≈7 due to the extremely weak basicity of the Cl− ion, which is the conjugate base of the strong acid HCl. In other words, NaCl has no effect on system pH in diluted solutions where the effects of ionic strength and activity coefficients are negligible."

You seem knowledgeable, I think in temps below 15 liquid calcium chloride was added to the salt for the plow trucks, remembering one guy saying it ate the soles off his shoes after walking on the mix.

Specifically it’s Sodium Bicarbonate, which when mixed with some water makes an excellent solution for cleaning battery terminals as it neutralizes the battery acid.