The distinctive tick noise on startup in your 2017 Jeep Grand Cherokee's 5.7L Hemi has become a common concern among owners. While often alarming, the causes range from benign to requiring attention, and understanding the source helps determine appropriate action.
Common Tick Sources
The Hemi tick can originate from several sources: hydraulic lifter bleed-down during extended parking, exhaust manifold bolt failures creating leaks, Multi-Displacement System (MDS) lifter issues, and rocker arm wear. Each produces slightly different tick characteristics.
Lifter Tick Characteristics
Hydraulic lifters can lose oil pressure when the engine sits, causing momentary tick until oil pressure rebuilds and refills the lifter. This tick typically disappears within seconds to a minute of startup. Persistent tick suggests collapsed or damaged lifters.
Exhaust Manifold Leak Tick
The Hemi's exhaust manifold bolts are notorious for breaking due to thermal cycling. A broken bolt creates an exhaust leak that ticks at startup but may quiet as metal expansion temporarily seals the gap when hot.
MDS System Considerations
The Multi-Displacement System deactivates four cylinders during light load operation. The MDS lifters are different from standard lifters and can develop problems causing tick during cylinder transitions or at idle.