The 2008 BMW 650i blends powerful V8 performance with elegant grand touring luxury. With its 4.8L N62 engine, aggressive styling, and refined interior, the 650i is an appealing choice for enthusiasts. But behind the smooth ride and premium features lies a set of mechanical and electrical quirks that can affect long-term reliability. This guide takes a detailed look at the 2008 BMW 650i’s reliability, known issues, and ownership experience.
Is the 2008 BMW 650i Reliable?
The 2008 BMW 650i is moderately reliable, but it requires consistent maintenance and a proactive approach to repairs—especially due to issues related to the N62 V8 engine and aging electronics. While it isn’t the most dependable BMW, it can be a great long-term vehicle if maintained properly and inspected regularly.
Major Components Affecting Reliability
1. Valve Stem Seal Failure
The N62 V8 engine is notorious for valve stem seal wear, leading to oil burning and engine smoke.
- Symptoms: Blue smoke from the exhaust, especially on startup or deceleration
- Fix: Replacing valve stem seals (complex job requiring engine work)
- Cost: $2,500–$5,000 depending on labor rates
2. Alternator Bracket Oil Leak
This unique oil leak on the N62 engine is difficult to spot but can cause major messes and lead to oil starvation if not fixed.
- Symptoms: Oil under the car near the alternator, dropping oil levels
- Fix: Remove alternator and reseal bracket housing
- Cost: $800–$1,500
3. Electronic Gremlins
Luxury features in the 650i are convenient but bring electrical headaches with age.
- Symptoms: Malfunctioning iDrive, Bluetooth issues, window regulators failing, random warning lights
- Fix: Diagnostic scan, module resets or replacements
- Cost: $100–$1,000+ depending on the component
4. Cooling System Failures
BMW’s cooling systems across the board tend to suffer from plastic components that wear out over time.
- Symptoms: Coolant leaks, overheating, low coolant warnings
- Fix: Replace radiator, hoses, expansion tank, water pump and thermostat
- Cost: $600–$1,200 for full refresh
5. Transmission Wear and Software Issues
The ZF 6-speed automatic is strong but suffers when fluid is never changed as per BMW’s “lifetime fluid” claim.
- Symptoms: Harsh shifting, gear slipping, delayed engagement
- Fix: Fluid and filter service, software update, or rebuild in extreme cases
- Cost: $400–$600 for service; $2,500–$3,500 for rebuild
6. Suspension and Control Arm Wear
At higher mileage, front suspension components begin to wear, especially under the weight of the V8 engine.
- Symptoms: Clunking over bumps, loose steering feel, uneven tire wear
- Fix: Replace control arms, bushings, ball joints
- Cost: $500–$1,000 for front-end refresh
7. Battery Drain and IBS Sensor Malfunction
Battery drain is a frequent complaint, often tied to the intelligent battery sensor (IBS) or control modules failing to shut off.
- Symptoms: Dead battery, slow crank, power drain after shutdown
- Fix: Replace battery and IBS, scan for parasitic draw
- Cost: $300–$600
Routine Maintenance for Reliability
To keep the 2008 650i running smoothly, stick to a strict maintenance schedule. Skipping routine service is the fastest way to shorten its lifespan.
| Service Item | Interval |
|---|---|
| Oil and filter change | Every 5,000–7,000 miles |
| Coolant flush | Every 3 years or 50,000 miles |
| Transmission service | Every 60,000 miles |
| Spark plugs | Every 60,000 miles |
| Valve cover gaskets | Every 80,000–100,000 miles |
| Battery and IBS check | Every 3–4 years |
Repair Cost Overview
| Repair | Estimated Cost |
|---|---|
| Valve stem seal repair | $2,500–$5,000 |
| Alternator bracket leak | $800–$1,500 |
| Cooling system overhaul | $600–$1,200 |
| Transmission service | $400–$600 |
| Suspension refresh | $500–$1,000 |
| Electrical diagnostics and repair | $150–$1,000+ |
How Many Miles Can a 2008 BMW 650i Last?
With proper maintenance, the 2008 BMW 650i can easily reach 150,000–200,000 miles. Many owners report crossing this threshold with minimal issues, but only if they stay ahead of known problems and use OEM-quality parts.
Who Should Buy a 2008 650i?
The 2008 650i is best for drivers who:
- Enjoy powerful V8 performance and grand touring comfort
- Have access to a reliable BMW specialist or are experienced DIYers
- Understand and budget for higher-than-average maintenance
Who Should Avoid It?
You may want to avoid this model if you:
- Want low-cost, worry-free ownership
- Are unfamiliar with BMW maintenance needs
- Cannot verify full service history
Final Verdict: Is the 2008 BMW 650i Worth It?
The 2008 BMW 650i can be a rewarding luxury coupe or convertible, but only for the right kind of owner. If you’re proactive with maintenance and understand the common issues—especially the valve stem seals, oil leaks, and electrical quirks—it can be a reliable and exhilarating daily driver or weekend cruiser. Ignore the warning signs, however, and it can quickly turn into a money pit.
Tip: Always get a pre-purchase inspection and service records if you’re buying used. Owning a 650i is about being smart, not lucky.