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u/yash_sonune

r/AskMechanics r/AutoMechanics
Image 1 — First car, bought AS-IS ($6,500), just saw the undercarriage — how cooked am I?
Image 2 — First car, bought AS-IS ($6,500), just saw the undercarriage — how cooked am I?
Image 3 — First car, bought AS-IS ($6,500), just saw the undercarriage — how cooked am I?
Image 4 — First car, bought AS-IS ($6,500), just saw the undercarriage — how cooked am I?
Image 5 — First car, bought AS-IS ($6,500), just saw the undercarriage — how cooked am I?
Image 6 — First car, bought AS-IS ($6,500), just saw the undercarriage — how cooked am I?
Image 7 — First car, bought AS-IS ($6,500), just saw the undercarriage — how cooked am I?
Image 8 — First car, bought AS-IS ($6,500), just saw the undercarriage — how cooked am I?
Image 9 — First car, bought AS-IS ($6,500), just saw the undercarriage — how cooked am I?
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First car, bought AS-IS ($6,500), just saw the undercarriage — how cooked am I?

TL;DR: New driver, bought a high-mileage Mazda CX-3 2016 as-is for cheap, mechanic gave it a green light before I signed, now I'm seeing rust on the undercarriage that mechanic apparently didn't flag as a dealbreaker (or I didn't push on). Trying to figure out if this is normal-for-the-age rust or a real problem before I get it safetied.

The car

  • 2016 Mazda CX-3 Sport, AWD
  • ~260,000 km
  • Bought from a used car dealer, as-is, $6,500 CAD all-in (HST included)
  • First car ever, I'm a new G2 driver
  • No accident history, one minor glass claim, single previous owner
  • 44 documented service records covering the car's whole life
  • Recent work done right before I bought it: full brake job, 4 new tires, alignment, front strut replacement

What I did before buying

  • Had a mechanic scan it with a diagnostic tablet — came back all green
  • Same mechanic test drove it, no complaints
  • Did not get a proper hands-on undercarriage inspection done before signing — in hindsight this was the gap

What I'm seeing now

Just got a real look at the undercarriage and there's noticeable rust on:

  • Rocker panels
  • Brake calipers
  • Possibly a perforated spot near the floor pan (not 100% sure how deep it goes)

Daily driving has been completely normal otherwise — no warning lights, no power loss, nothing. The only symptom is an occasional creaking sound when braking.

After a closer look

  • The car sat parked outside for 3-4 months before I got it — there's surface rust on bolts and hardware pretty much everywhere, including inside the cargo area, which lines up with general weather exposure rather than anything caliper-specific
  • That said, the brake caliper carrier shows heavier corrosion than the surrounding area — possible sticking/seized slide pins, which could explain the creaking
  • Not sure yet if the calipers themselves were actually replaced during the recent brake job, or just pads/rotors
  • Heat shield looks bent or partially detached
  • One localized spot has noticeably more advanced rust than the rest of the underbody — needs a hoist and a proper probe to confirm whether it's just surface or actual perforation

Photos

(attach here: full undercarriage overview, rocker panels close-up, calipers, the suspect floor pan area, the heat shield, and the brakes)

What I'm actually trying to figure out

  1. Is this normal surface rust for a 10-year-old car that's done Ontario winters, or does this look structural/perforated?
  2. Does the caliper carrier corrosion look like plain surface rust from sitting, or does it look like something that's already affecting function?
  3. Realistically, how much extra should I budget for safety certification + repairs + rustproofing + full service on top of the $6,500?
  4. Given the rest of the history (single owner, full service records, recent brake/tire/strut work), would you have walked from this deal at this price — or is this a fairly normal tradeoff for what I paid?

Plan so far

  • Taking it to an independent shop with zero connection to the purchase to get the Ontario Safety Standards Certificate — treating this as a real inspection, not a formality
  • Getting rustproofing done within the next couple weeks regardless of what the safety turns up
  • It's an as-is sale, so any repairs needed to pass safety are on me either way

Appreciate any eyes on this — especially from anyone who's dealt with CX-3s specifically or knows what's "normal" vs "run" for a Southern Ontario winter car at this age/mileage.

u/yash_sonune — 14 hours ago