Before You Buy: The Complete Checklist
A used car purchase is a significant investment. This checklist helps you avoid costly mistakes and recognize the true condition of a vehicle - specifically optimized for BMW, Mercedes and Audi.
Phase 1: Initial Visual Inspection (15 Minutes)
Exterior
| Check Point | What to Look For | Warning Sign |
|---|
| Paint | Even color tone | Color differences, orange peel |
| Panel gaps | Even, symmetrical | Unequal spacing |
| Rust | Wheel arches, sills, door edges | Bubbling, rust-through |
| Glass | Original, no cracks | Aftermarket glass, stone chips |
| Tires | Tread depth, even wear | Uneven wear pattern |
Quick Accident Damage Check
| Test | Method | Suspicious When |
|---|
| Magnet test | Magnet on body panels | Doesn’t stick (filler) |
| Gap check | Check all door gaps | Uneven widths |
| Screw heads | Fenders, hood | Paint marks, turned |
| Stickers | Check original stickers | Missing, shifted |
Phase 2: Interior Inspection (10 Minutes)
General Condition
| Area | Check Points | Cost Factor |
|---|
| Driver’s seat | Bolster wear, tears | €500-2,000 |
| Steering wheel | Wear, damage | €300-800 |
| Pedals | Wear matching mileage | Manipulation sign |
| Headliner | Sagging (BMW E39, E38) | €400-1,000 |
Electronics Quick Test
| System | Test | Common Problem |
|---|
| Windows | All 4 windows up/down | BMW: regulator, Mercedes: motor |
| A/C | Does it actually cool? | €800-2,500 repair |
| Seat adjustment | All functions | Mercedes: pump, BMW: motor |
| Navigation | Starts and works | Outdated software |
Phase 3: Engine and Mechanicals (20 Minutes)
Cold Start Test (IMPORTANT!)
Always schedule an appointment with a cold engine!
| Observation | Normal | Warning Sign |
|---|
| Starting | Immediate, quiet | Cranking, hesitation |
| Idle | Smooth | Fluctuating, jerking |
| Exhaust color | Invisible/slight | Blue (oil), White (coolant), Black (mixture) |
| Sounds | Even | Rattling, knocking, whistling |
Engine Bay Inspection
| Check Point | What to Check | Cost if Faulty |
|---|
| Oil level | Level, color, consistency | Engine damage possible |
| Coolant | Level, color (not brown!) | €500-3,000 |
| Timing belt/chain | Change interval, documentation | €800-4,000 |
| Gaskets | Oil traces, leaks | €500-2,000 |
| Hoses | Porous, cracks | €200-500 |
Brand-Specific Engine Checks
BMW
| Engine | Critical Point | Cost Factor |
|---|
| M52/M54 (6-cyl) | VANOS seals | €500-1,200 |
| N52/N53 | VANOS, valve cover | €600-1,500 |
| N47 (Diesel) | Timing chain | €2,000-4,000 |
| M62/N62 (V8) | Chain guides | €2,500-5,000 |
| S85 (M5 V10) | Rod bearings | €5,000-15,000 |
Mercedes
| Engine | Critical Point | Cost Factor |
|---|
| M112/M113 (V6/V8) | Intake manifold gasket | €400-800 |
| M272/M273 | Balance shaft gear | €2,000-4,000 |
| OM642 (V6 Diesel) | Injector seals | €800-1,500 |
| M156 (AMG V8) | Camshaft wear | €3,000-6,000 |
Audi
| Engine | Critical Point | Cost Factor |
|---|
| 1.8T | Turbo seal, crankcase | €800-2,500 |
| 2.7T | Turbocharger, water pump | €1,500-4,000 |
| 4.2 V8 | Timing chain | €3,000-6,000 |
| 2.0 TDI (PD) | Camshaft | €1,000-2,000 |
Phase 4: Test Drive (30 Minutes)
Route Planning
Plan a route with various conditions:
- City traffic (10 min) - Stop-and-go, steering
- Country road (10 min) - Acceleration, gearbox
- Highway (10 min) - High speed, vibrations
Check Points During Drive
| Area | Test | Watch For |
|---|
| Steering | Straight-line stability | Pulling to one side |
| Gearbox | All gears | Sticking, grinding, slipping |
| Brakes | Hard braking several times | Vibration, pulling |
| Suspension | Speed bumps | Clunking, rattling |
| Clutch (manual) | Hill start | Slipping, juddering |
Sound Analysis
| Sound | Possible Cause | Cost |
|---|
| Rattling at start | Timing chain | €1,500-4,000 |
| Whistling on throttle | Turbo/intake issue | €500-3,000 |
| Clunking front | Ball joints, strut mounts | €300-800 |
| Humming at speed | Wheel bearing | €200-500 per side |
| Clicking when turning | CV joint | €300-600 |
Phase 5: Document Check
Required Documents
| Document | Check Point | Warning Sign |
|---|
| Title/Registration | Number of owners | Many short-term owners |
| Inspection report | Last inspection | Defects, conditions |
| Service book | Complete history | Missing stamps |
| Invoices | Major repairs | None available |
Mileage Plausibility
| Check | Method |
|---|
| Service book | Mileage chronological |
| Inspection reports | Mileage at each inspection |
| Invoices | Date/mileage comparison |
| Online check | CARFAX, AutoCheck |
Phase 6: Price Check
Valuation Factors
| Factor | Price Impact |
|---|
| Mileage | +/- 10-20% depending on deviation |
| Accident damage | -20 to -50% |
| Service history | +5-15% if complete |
| Equipment | +5-20% for premium |
| Condition | +/- 15% |
Negotiation Basis
| Defect | Typical Deduction |
|---|
| Minor scratches | €200-500 |
| Windshield chips | €300-600 |
| Worn tires | €400-800 |
| Due maintenance | Workshop estimate |
| Technical defects | 1.5x repair costs |
Quick Reference: Red Flags
- Seller pressures for quick sale
- Engine cannot be cold-started
- No test drive possible
- Documents missing or inconsistent
- Price significantly below market without explanation
Be cautious with:
- Freshly washed/polished (hides defects)
- “Garage kept” without proof
- “Full service history” without documentation
- Many owners in short time
- Import vehicle without clear history
Printable Checklist
On Site
After Viewing
Conclusion
A thorough inspection takes 60-90 minutes but can save thousands. Take your time, use this checklist, and don’t let yourself be pressured. When uncertain: an independent inspection (€150-300) is always worth the money.
This checklist is based on our experience with hundreds of vehicle evaluations. As of: February 10, 2025