OM654 Extended engine crank or starting concerns and/or poor running characteristics Complaint One or more...

Bulletin number

LI05.30-N-080518

Component

Engine

Summary

OM654 Extended engine crank or starting concerns and/or poor running characteristics Complaint One or more of the following may be reported: • Extended crank or hard start • Rough idle or misfire like condition • Engine stalls during low-speed maneuvering Cause In some cases, one or more exhaust valves may be leaking due to: • Burnt exhaust valve seat rings • Burnt valve faces • Heavy carbon buildup on the exhaust valve seat leading to poor sealing Remedy Follow the steps below in order. Do not replace components before completing verification. 1. Initial check • Perform a quick test with XENTRY Diagnosis • Check for stored or pending fault codes 2. Fuel system verification • Using XENTRY Diagnosis, monitor actual values during cranking under: “Engine start – starter turning, engine not starting” • Check rail pressure during cranking Evaluation: • If rail pressure is below specification: diagnose fuel system per WIS • If rail pressure is within expected range (approximately 250 to 300 bar): proceed with mechanical checks 3. Compression evaluation Perform compression test per WIS (engine at operating temperature if possible): • Manual compression test per WIS doc AR01.00-D-1201TSM • If compression is out of specification, continue to leak down testing 4. Cylinder leakage test • Perform cylinder leakage test on all cylinders per WIS doc AR01.00-D-1300TSM • Ensure test equipment is calibrated before testing Evaluation: • Leakage confirmed through exhaust path → suspect exhaust valve sealing • Leakage into crankcase → do not proceed; submit TIPS case for further direction 5. Additional validation (if needed) • Smoke test may be used to confirm leakage path Repair If leaking or burnt exhaust valves are confirmed: • Replace the complete cylinder head assembly with valves pre-installed Do not attempt partial repair of affected valves or seats.

Owners of these vehicles have filed 9 complaints in the engine category.