bpawnzZ/lemonwrench

LemonWrench — automotive repair research

Turns "how do I replace X on " into a procedure, a torque table, and labelled figures — then cross-checks it against a parts catalog and real-world field notes so you don't chase a step the manual left out.

Primary source: https://lemon-manuals.la — ~10,000 US/Canada vehicles across 69 makes, 1960–2025, free, no login. Domestic, import, orphan brands (Pontiac, Oldsmobile, Saturn, Saab, AMC, Geo, Mercury, Suzuki), Euro exotics, trucks/commercial, and modern EVs (Tesla 2012→, Rivian 2022→). Years run deep, not just recent: Toyota and Ford carry 66 straight model years. Real HTML text (torque tables, capacities, step-by-step), figures at /images25/. Not scanned PDFs.

Two databases per model year:

DB	Source	Use it for
LEMON	2025 capture	2010+, current TSBs, complete trees, figure captions
CHARM	2013 DVDs	1990s–2000s, finer detail, trees truncated at depth

The three-source rule

A manual alone is not an answer. Every confident answer here comes from three:

1. The manual — the procedure and the torque figures.
2. A parts catalog (gmpartscenter.net, gmpartsdirect.com, rockauto, etc.) — part numbers, and structural proof: if two castings are separate parts, they're separate parts. This is how you answer "is this bracket part of the cover?" without guessing from a photo.
3. Field consensus (model forums, JustAnswer/identifix threads, YouTube transcripts) — the steps the manual omits because the engineer never turned the wrench. Say plainly when a step is field consensus rather than manual text.

If the three disagree, report the disagreement. Never paper over it.

The tool

S=scripts/lemon.py
python3 $S <cmd>

Command	Purpose
makes	canonical make names
years MAKE	model years present
cars MAKE YEAR [regex]	vehicles for that year, tagged [LEMON] / [CHARM]
index VEHICLE [--refresh]	fetch + cache the whole link tree (once per vehicle)
find VEHICLE TERM... [-n N] [--strict|--any]	grep the cached tree
read VEHICLE TERM... [-k N]	render the Nth hit, auto-following hub sub-pages
get URL	render one page by absolute URL
sub URL	child pages under a hub
imgs URL / pic URL / note URL TEXT / notes [URL]	figure pipeline + persistent cache
selftest	parser checks, no network

VEHICLE is the site path minus slashes: Toyota/2015/Camry LE, Pontiac/2007/G6 V6-3.9L.

Workflow

1. Resolve the car properly. cars MAKE YEAR lists every variant. Engine and trim change the manual — G6 GT, 4D Sedan, 3.9 1, Automatic is a different book from G6 GT, 4D Sedan, 3.5 N. Say which variant you used. Note that a badge can lie: the same nameplate shipped with several engines, so confirm displacement.
2. Index once. LEMON single-page tree ≈ 5.5 MB / 13k links, CHARM split tree ≈ 1.3 MB. Cached at ~/.cache/lemon/<hash>.idx; later queries are local greps. --refresh only when the site adds manuals.
3. Search in site vocabulary — removal, installation, disassembly, torque specifications, fluid capacities, valve clearance, component locations, wiring diagram, DTC, labor times. Default allows one unmatched term; --strict for exact, --any for one-word fishing.
4. Read, and escalate. read prints hits then the best page's text then follows sub-pages. CHARM trees are depth-truncated: a hub page often lists nothing until you sub <url> and then get <url>. Two-level escalation is normal, not a bug.
5. Answer: numbered steps, torques exactly as printed, page URL, and a confidence note per claim (manual / catalog / field).

Figures

read/get emit [FIGURE https://lemon-manuals.la/images25/XXXX/] lines, with a cached description appended when one exists.

python3 $S pic https://lemon-manuals.la/images25/GM1557668/   # -> ~/.cache/lemon/img/GM1557668.png
# view it, then:
python3 $S note https://lemon-manuals.la/images25/GM1557668/ "right rocker cover, bolt ring, coil bracket above"

Captions in the page text (Fig 1: View Of Right Valve Rocker Arm Cover) are the figure's real title — use them, they're accurate even when the scan is illegible. 1-bit line art reads fine at full size. Worth looking at: exploded views (they carry torque callouts the text omits), wiring diagrams, connector end views.

Descriptions persist in ~/.cache/lemon/imgnotes.json — describe a diagram once and it's text forever.

Beyond the manual

• Structural questions ("is this part of the timing cover?") → parts catalog. Separate part number + separate gasket = separate casting. The catalog diagram also tells you which sub-assembly a fastener belongs to.
• Access questions ("what's blocking this bolt?") → field sources. Search <year> <model> <engine> "<part>" bracket bolt and read the forum/JustAnswer threads; dealer techs post the missing steps.
• Whether a tool is needed (pressed-on pulley, Torx, stud) → the removal procedure's preliminary steps; they name the special tools (e.g. J 25034-C).
• Bolt torque for a part you can't identify → torque table by component name, then confirm the casting by part number. Same-looking brackets on one engine often carry different specs (e.g. 25 N·m vs 50 N·m on adjacent parts).

Answering rules

• Quote torques exactly, all three units: 34 N*m (350 kgf*cm, 25 ft*lbf).
• Call out low-torque fasteners explicitly (valve covers, plastic/composite covers): over-torquing into aluminium is the top cause of repeat leaks and pulled threads.
• [09/2014 - ] in a path is a revision date — that page applies from then on.
• LEMON pages often say the manual "is identical to the following model variants, except possibly Labor Times, Fluids, and Tire Fitment" — reuse instead of re-searching.
• <vehicle>/Labor Times/ lists Remove & Replace operations; if it says "only available for a different vehicle variant", use the variant it names.
• Not covered? Say so plainly and name the nearest covered year. Never invent a spec.
• Sequencing matters: give the prerequisite chain (belt → accessory → bracket → cover), not just the cover bolts.

Deliverable

Write the result as a standalone markdown note, not chat prose:

• frontmatter (tags, vehicle, job, status, updated)
• status callout — where the job actually stands
• the direct answer to the blocking question, first
• numbered procedure per side/component
• one torque table covering every fastener touched
• captioned figure embeds
• sources/confidence table — claim, source, verified / field consensus

See examples/ for a complete worked note.

Gotchas

• URLs are case-sensitive and the make spelling is the site's (Dodge and Ram, Mercedes Benz); canon_make handles it, manual curl does not.
• Trailing slashes matter on every directory URL.
• /bundle/ zip downloads are disabled (303 → /static/sad.html). robots.txt disallows /bundle/ too.
• /hyperlink/... URLs are the cross-reference resolver, not content.
• Paths contain version tags and %2F-encoded slashes: fetch only the absolute URL the tool printed; re-quoting a decoded path 404s.
• Banner "back up on a temporary server / slowness possible" is skipped by the parser; allow 120 s timeouts.
• Mirrors if the main host dies: lemon-manuals.org.ua, lemon-manuals.gy, lemon.dogeware.me — LEMON_BASE=https://… overrides.
• Miniforge/pyenv pythons often ship no CA bundle; lemon.py falls back to /etc/ssl/certs/ca-certificates.crt.

Verify

python3 scripts/lemon.py selftest      # expects: selftest OK