Persistent Hemi Tick on my 2018 Ram 1500 5.7L Laramie

ClearTheCode admin answer:

The 'Hemi Tick' is a well-known issue, often attributed to the Multi-Displacement System (MDS) lifters or exhaust manifold leaks. Here's a breakdown of potential causes and steps:

1. Exhaust Manifold Leak: This is a common and often mistaken cause for a ticking sound. Over time, the exhaust manifold bolts can break or loosen, creating a small leak that sounds very similar to a lifter tick. This is usually more pronounced when cold and can sometimes lessen as the engine heats up and components expand.
2. MDS Lifter Failure: The MDS system deactivates cylinders for fuel economy. The lifters associated with this system are known to fail, causing a distinct ticking or knocking sound. If a lifter fails completely, it can damage the camshaft.
3. Oil Viscosity/Quality: While you mentioned using recommended oil, ensuring you're using a high-quality synthetic oil and changing it at appropriate intervals (or even slightly more frequently) can sometimes help mitigate minor lifter noise.
4. Oil Pressure: Low oil pressure can starve lifters. A faulty oil pressure sensor or a worn oil pump could be contributing factors, though less common for just a tick.

Diagnostics:

• Listen carefully to pinpoint the sound's origin. An exhaust leak will typically be louder near the manifold.
• Check for exhaust manifold bolt presence and tightness.
• If the sound is internal, an OBD-II scan might reveal misfire codes (P030x) if a lifter is severely failing, but often, early lifter tick doesn't trigger codes.

When to See a Shop: If the ticking is getting louder, accompanied by a check engine light (especially with misfire codes), or if you notice a loss of power or rough idle, it's crucial to get it inspected by a qualified mechanic immediately. Continued driving with a failing lifter can lead to significant engine damage, including camshaft wear or even catastrophic engine failure.