modbender Decision Tree
| Situation | Action |
|---|---|
| Buying a car | Check buying.md for price negotiation, inspection checklist, financing |
| Maintenance due or warning light | Check maintenance.md for schedules, DIY vs mechanic, symptom diagnosis |
| Breakdown or accident | Check emergencies.md for immediate steps, who to call, documentation |
| Road trip planning | Pre-trip checklist below, then emergencies.md for kit and what-ifs |
Pre-Trip Checklist
Before any long drive:
- Tire pressure (including spare) at recommended PSI
- Oil level between min/max marks
- Coolant reservoir at proper level
- All lights working (headlights, brake, turn signals)
- Windshield washer fluid filled
- Wiper blades not streaking
- Phone charger and emergency contact numbers accessible
Warning Lights — Quick Reference
| Light | Severity | Action |
|---|---|---|
| Check engine (steady) | Medium | Safe to drive, diagnose within days |
| Check engine (flashing) | Critical | Stop driving, call tow |
| Oil pressure | Critical | Stop immediately, check oil level |
| Temperature/coolant | Critical | Pull over, let engine cool, check coolant |
| Battery | Medium | Drive to shop, may have 30-60 min before stall |
| ABS | Low | Brakes work, but ABS disabled — drive carefully |
| Tire pressure | Low | Check and inflate soon |
Cost Sanity Check
Before approving any repair, verify the quote:
- Get the exact repair name (not "fix the engine")
- Search "[repair name] + [car model] + cost" for typical range
- Labor: $80-150/hr is normal; over $200/hr is premium/dealer
- If quote is 50%+ above average, get a second opinion
Common repairs (USD):
- Oil change: $30-75
- Brake pads (pair): $150-300 installed
- Battery replacement: $150-250
- Alternator: $400-600
- Timing belt: $500-1000
Fuel Efficiency Tips
- Optimal highway speed: 55-65 mph (above 65, efficiency drops ~15%)
- Tire pressure: check monthly, underinflation costs 0.2% per PSI
- AC vs windows: AC more efficient above 45 mph
- Remove roof racks when not in use (5% drag penalty)
- Avoid idling more than 30 seconds
When to Load More
| Situation | Reference |
|---|---|
| Buying new or used, financing, negotiation | buying.md |
| Maintenance schedules, DIY repairs, diagnostics | maintenance.md |
| Accidents, breakdowns, insurance claims | emergencies.md |