Red flags in by-owner listings: a working ladder

2026-09-11 — sourcing method for used-car flippers, about 1,000 words.

Every experienced flipper has a short private list of listing phrases they'll walk on, another list that means "great deal if priced right", and a longer list of noise. Getting these three lists wrong is expensive on both sides: the fatal-list-too-short flipper buys a salvage title and eats it, and the fatal-list-too- long flipper never buys anything.

Below is the exact ladder FlipScout ships in src/score.js, written out for a human. Fatal drops a listing's rank to zero. Major discounts it hard. Minor barely nudges it. Every regex was written against real strings from Autotrader by-owner listings; the "why" for each entry is below.

Fatal — walk unless you're a mechanic buying at scrap

These are the phrases that turn a "flip" into "expensive shop project" or "title problem I can't sell out of":

• branded-title — "salvage title", "rebuilt title", "reconstructed title", "branded title", "flood title", "salvage vehicle". Also matches "title is salvage / rebuilt / etc.". Non-recoverable: a branded title cuts the resale price 40–60% and disqualifies most retail buyers' financing. Note: bare "rebuilt engine" or "rebuilt transmission" does not fire this — those are component rebuilds, not title brands. That was a real 2026-09-11 correction to the scorer.
• no-title — literally "no title". If the seller can't produce a title, you can't transfer it, you can't register it, you can't sell it.
• parts-only — "parts only" / "parts-only". The seller has already told you the car isn't a flip.
• doesnt-run — "does not run / start / crank / drive / move", or the contractions. If you have to tow it home you've absorbed the first $150 before you've turned a wrench.
• engine-blown — "blown / knocking / seized / cracked engine", or "engine is blown / knock(ing / s) / seized / dead / failed / failure". Engine replacement on a cheap car is usually the whole margin.
• trans-failure — "transmission slips / slipping / failed / failing / needs / shot / gone / dead", or the noun form. Same math as engine — the repair is bigger than the flip.
• cvt-issue — "CVT issue / problem / failure / slip / shudder". Certain Nissan and Subaru CVTs are $4k–$6k to replace on a $5k car.
• hybrid-battery — a hybrid or EV battery in a failure-context word (charging issue, dead, weak, dying, degrading, failing, hybrid battery). Explicitly does not fire on "battery replaced" or "battery replacement" — that's a service brag, not a red flag.
• mechanic-special — the phrase is code for "budget the transmission." Not a fit for a flipper without a shop.
• flood-damage — "flood", "flooded", "water damage", "submerged". Electrical harnesses that got salt water in them keep failing for years after the water dries.

Major — negotiating leverage, price it in

These are real problems but priceable ones. The right move is usually a lower offer, not a walk:

• as-is / needs-work — "as is", "as-is", "needs work / repair / repairs / TLC / attention / fixing". The seller is telling you they're moving the car quickly for less. Bring a scanner.
• check-engine / warning-light — the light is on, or the ABS / airbag / traction light. Usually a $50–$500 fix; sometimes a catalytic converter. Read the codes before you commit.
• misfire — an actual "misfire" mention, or a P0-series code. Ignition coil / plug / injector; occasionally a compression issue. Cheap to diagnose, sometimes not cheap to fix.
• burns-oil — "burns oil", "smokes", "leaking oil / coolant / transmission / head". PCV valve, valve seals, head gasket. The valve-seal answer is $300; the head-gasket answer is $2,000. Diagnose before offering.
• lien — "lien", "loan on", "still financed". You can't take title until the lien is paid off, and coordinating with the seller's bank adds a week. Not fatal, but adds friction; discount your offer for your time.
• accident — the word "accident" or "accidented" appears. Pull a CarFax; scale the discount to the damage severity and whether it's on record.
• body-damage — "minor / slight / small / light damage". Usually a quarter panel, sometimes a bumper. Cheap to fix if you have a body guy on speed dial.

Minor — noise, but worth surfacing

These barely move the rank. They're on the list because a scored report is more useful when it tells you what it saw, even if it isn't scaring you off:

• engine-work — "engine replaced", "engine swap", "new engine", "rebuilt engine". A component rebuild is usually a positive service signal for a flipper, but the original engine failed for a reason; ask what.
• modified — coilovers, aftermarket suspension / exhaust / tune, "tuned", "modified", "modded". Cuts the retail buyer pool; sometimes cuts it in half. Neutral if you're targeting an enthusiast segment; discount if you're not.
• cosmetic — literally "cosmetic" / "cosmetics" / "cosmetically". The seller is admitting cosmetic issues; usually you can see them in the photos.
• scratches, dent, dents — literal words. If they photographed it, it's real.
• sunroof-leak — "sunroof leak / leaks / leaking". Usually a drain-tube clean; sometimes a whole moonroof cassette. Priceable.

The three phrases that look like red flags but aren't

FlipScout's ladder is deliberately narrow. The phrases below look scary but the scorer intentionally ignores them:

• "Battery replaced" / "new battery" — a service brag, not a hybrid failure. The hybrid-battery regex requires both "battery" and a failure-context word; a bare "recently replaced the battery" doesn't fire.
• "Rebuilt engine" / "rebuilt transmission" — component rebuild, not title brand. This turns into a engine-work minor chip. The branded-title regex requires the actual word "title" near the qualifier.
• "Runs great", "new oil, new brakes, new tires" — zero flags. Service history is exactly what you want to see on a flip candidate.

How to use the ladder

On any given scan, the fatal-flagged rows drop out of the top twenty-five automatically. The major-flagged rows stay in the report but with a lower rank; treat them as "OK if you're already at the seller's house with a scanner". The minor rows are still-good candidates that just have a quirk worth mentioning.

The ladder is deliberate. Every phrase on it is a real string from a real listing FlipScout scored during v0.1 development. New phrases get added when a real listing surfaces one — not from a legal team's wish list.

If you catch a phrase FlipScout is missing, or a false positive it's firing on, email support@flipscout.dev with the listing URL. Every ladder change lands with a test.