Understanding Timing Chain Stretch
Timing chain stretch occurs when the metal links of the chain elongate over time due to wear, or when tensioners fail to maintain pressure. On the Mercedes M278/M157 (Check Valves) and BMW N20/N63 (OG) engines, this is a critical failure point that can lead to jumped timing and catastrophic engine damage.
Symptoms
- Rattle on cold start (2-3 seconds)
- Check Engine Light (P0016/P0017)
- Chassis Stabilization Error (BMW)
- Metallic slapping noise
At A Glance
- Repair Cost:
- $3,000 - $7,000
- Prevention:
- Change oil every 5,000 miles. Install updated check-valves (MB) or updated tensioners (BMW).
Affected Vehicles & Guides
The following detailed guides cover Timing Chain Stretch specifically for the listed models.
BMW 750i N63: Known Problems, Failure Rates & What to Expect
A survival guide for the BMW 750i (F01/G11) with the N63 V8. Detailed costs for Valve Stem Seals, Air Suspension, and Injectors.
Reliability: 38
/100
Read Guide →
BMW X5 50i (N63): Engine Issues & Reliability Warning Guide
The BMW X5 50i (E70/F15) combines the N63 V8 with a heavy SUV chassis. Learn why this specific combination leads to rapid timing chain and turbo failures.
Reliability: 40
/100
Read Guide →
Disclaimer: Repair costs are estimates based on independent
specialist rates. Dealer prices will significantly exceed these figures.
