The 2019 Dodge Charger's 5.7L Hemi V8 promises V8 power with V6-like fuel economy thanks to Multi-Displacement System technology. But for thousands of owners, MDS has become synonymous with one of the most frustrating—and expensive—failures modern Hemis experience: collapsed lifters. If you're hearing a tick, feeling a misfire, or watching your oil pressure gauge nervously, this guide explains what's happening inside your engine.
How MDS Works
The Multi-Displacement System deactivates cylinders 1, 4, 6, and 7 during light-load cruising. Special solenoid-actuated lifters lock and unlock to disable valve operation on those cylinders. When you're cruising at highway speeds with minimal throttle input, your V8 essentially becomes a V4, saving fuel. Brilliant engineering—when it works.
Why MDS Lifters Fail
Internal Complexity
Standard lifters are relatively simple hydraulic components. MDS lifters contain additional mechanisms: a locking pin, spring, and solenoid-activated piston. More moving parts mean more potential failure points, especially under the stress of rapid cycling between active and deactive states.
Oil Contamination Sensitivity
The tight tolerances inside MDS lifters make them highly sensitive to oil quality. Contamination, sludge, or even slightly degraded oil can cause the locking mechanism to stick or fail to engage properly. Extended oil change intervals common in modern vehicles can accelerate this.
Design Weakness
The needle bearings inside certain MDS lifters have been identified as a weak point. When these bearings fail, they can disintegrate, sending metal debris throughout the engine's oil system—potentially causing catastrophic damage.
Symptoms of MDS Lifter Failure
- Tick or tap at idle: The classic symptom—a rhythmic ticking that may or may not fade when the engine warms up
- Misfire codes: P0300 (random misfire) or cylinder-specific codes on MDS cylinders (1, 4, 6, 7)
- Check engine light: Often accompanied by codes P3400 or P3441 (cylinder deactivation system)
- Loss of power: If lifters fully collapse, that cylinder contributes nothing
- Metal in oil: Severe failure sends bearing material throughout the oiling system
Diagnosing the Problem
- Code scan: Check for MDS-related codes and cylinder-specific misfires.
- Oil analysis: Send a sample to a lab like Blackstone. Elevated copper, aluminum, or iron indicates internal wear.
- Cylinder balance test: Compare power contribution from each cylinder.
- Listen and locate: Use a stethoscope to identify which lifter(s) are making noise.
- Visual inspection: Removing the valve covers allows direct inspection of lifter behavior.
Repair Options
Single Lifter Replacement
Replacing just the failed lifter is possible but not recommended. Other MDS lifters are likely near failure, and you'll have the engine apart again soon. Cost: $1,500-$2,500.
All MDS Lifter Replacement
Replacing all eight MDS lifters with new OEM units addresses immediate concerns but doesn't solve the fundamental design weakness. Cost: $2,500-$3,500.
MDS Delete Kit
The most comprehensive solution replaces all MDS lifters with standard lifters, installs a non-MDS camshaft, and requires ECU tuning to disable the MDS function. This eliminates the failure-prone components entirely. Cost: $3,000-$5,000.
Is the MDS Delete Worth It?
For many owners, yes. The modest fuel economy benefit of MDS (1-3 MPG improvement in ideal conditions) rarely justifies the repair cost when lifters fail. An MDS delete provides:
- Elimination of a known failure point
- Improved peace of mind
- Often a slightly more aggressive exhaust note
- Potential for additional cam upgrades if desired
The downside is losing the cylinder deactivation feature and potentially affecting warranty coverage if other powertrain issues arise.