Who charges it
- Imposed by
- the dealer, as an optional product
- Legal status
- Optional — never required to buy the car or get the loan
- Negotiable?
- Yes — typically removable from the order
- Attention level
- medium
Dealer add-ons
Rust Protection
Aftermarket corrosion protection applied by the dealer. Value depends heavily on climate and road-salt exposure; modern factory corrosion warranties already cover perforation.
Negotiable: Yes — typically removable from the order
Benchmark range
$100–$400
typical $250
Carlarity estimate · confidence low — this range is Carlarity's own starting hypothesis, not a published benchmark.
Independent undercoating shops; higher value in salt-belt climates
- Carlarity operator benchmark (starting hypotheses from the 2026-09-07 brief, cross-checked against dealer F&I menus) — F&I ancillary product starting ranges (secondary source, accessed 2026-09-07)
The form shows $499 beside this line as a catalog hint only. The report uses the price you enter from your own quote, never this figure; it is not a market benchmark.
Why it matters
Manufacturers already warrant against rust perforation for years. Aftermarket undercoating can add value in heavy road-salt regions, but it is optional everywhere and often priced well above independent shops.
What to ask at the desk
“Please confirm what product was applied and its warranty, and remove the charge if the vehicle will not be driven in a road-salt climate.”
What Carlarity evaluates
- Classifies the line as rustproofing / undercoating from its name and aliases, and priced against a Carlarity estimate range.
- Compares the quoted amount with the benchmark range above and states any potential excess as a range, never a point estimate.
- Checks the coverage term against the factory warranty still in force, and states the overlap.
- Keeps government, manufacturer and lender charges out of the negotiable total by construction.
Reading this page
Legal and expensive are two different questions. An optional product can be entirely legitimate and still cost more on the buyer’s order than the same coverage elsewhere; a low-value item can be fairly priced. This page tells you what the product is, who is charging for it and what a Carlarity estimate range looks like. Your report judges your actual quote against that range, as part of the whole deal.
Benchmarks are ranges, not exact prices: a published benchmark comes from the sources cited, and a Carlarity estimate is our own starting hypothesis and is labelled as such. We last reviewed them 2026-09-07 and prices move after we look. Nothing on this page is legal or financial advice. The product’s contract terms decide its value on your deal.