The infamous "Hemi tick" in your 2017 Ram 1500 at 100,000 miles joins countless other 5.7L Hemi engines making this controversial sound. Understanding what it is - and isn't - helps you decide whether to address it or accept it.
What is the Hemi Tick?
The Hemi tick is a rhythmic tapping noise, typically from the top of the engine, most noticeable at idle. It's been present in Hemi engines since their modern introduction in 2003. The debate continues whether it's a design characteristic or a problem requiring attention.
Possible Causes
Exhaust manifold bolts are known to break, creating an exhaust leak that ticks. The MDS (Multi-Displacement System) lifters can tick when engaging or disengaging. Roller lifter wear creates ticking. Some attribute it to loose tolerances in the valvetrain. The actual cause varies by individual engine.
Code P0300 Connection
If the tick is accompanied by misfire codes, especially on MDS cylinders (1, 4, 6, 7), the issue may be lifter-related affecting combustion. A tick without misfire codes is more likely exhaust manifold or benign valvetrain noise.
To Fix or Not to Fix
Many Hemis tick for hundreds of thousands of miles without issue. If the tick is steady and not worsening, monitoring may be appropriate. Broken manifold bolts should be addressed as they affect emissions and can worsen. MDS lifter issues may warrant attention if causing misfires.