RAM 1500: 5.7L Hemi MDS Multi-Displacement Lifter and Cam Lobe Failure

RAM's Multi-Displacement System (MDS) on the 5.7L Hemi operates identically to GM's AFM – collapsing lifters deactivate four cylinders under light load. The same failure mode applies: oil passages to MDS lifters restrict, lifters stick in the collapsed position, and associated camshaft lobes wear rapidly. NHTSA received hundreds of complaints. The failure progresses from a cold-start tick to full cam destruction and engine contamination with metal debris. Affects a high proportion of 2009-2018 Hemi-equipped RAM 1500s in NZ/AU used market.

• Persistent lifter tick at idle, often worse when cold
• Cylinder-specific misfire codes on OBD scan
• Elevated oil consumption alongside engine tick
• MDS system diagnostic fault codes
• Metal contamination visible in oil

1. 1

   Warm idle and listen for valve train tick.

2. 2

   Scan for MDS or camshaft fault codes.

3. 3

   Check oil for metallic contamination.

4. 4

   Ask specifically if an MDS delete (lifter replacement + cam) has been done – this is a known pre-sale repair.

$3,500 to $9,000 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Has an MDS delete been performed – lifters and camshaft replaced?”
• “Any ticking from the engine or oil consumption beyond 1L per 5,000 km?”
• “Has the camshaft or lifters been replaced under any warranty or recall?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.