The 5.7L Hemi's Multi-Displacement System (MDS) lifters have a well-known failure pattern - they collapse on cylinders 1, 4, 6, and 7, often taking the camshaft with them. It's the same root cause as GM's AFM lifter failure, and the same fix applies. Here's what to watch for, what it costs, and why an MDS delete tune is the most common permanent solution.
MDS lifter failure typically requires camshaft + lifter replacement. Most affected: 2009-2014 trucks and SUVs with the 5.7L Hemi. A loud tick at idle, misfires on cylinder 1, 4, 6, or 7, and a check engine light are the classic warning signs.
The deactivating MDS lifters lose their internal pin-lock mechanism, collapse, and hammer the cam lobe flat. You hear a loud diesel-like tick at idle, get a P0301/P0304/P0306/P0307 misfire, and lose power. Repair almost always means a full cam + lifter job.
View P0301 Diagnosis →Even non-MDS cylinders see rocker arm bearing wear and roller failure on high-mile Hemis. Symptoms overlap with lifter failure - tick, misfire, metal in oil. Often discovered during the lifter job.
Run free diagnosis →Once a lifter collapses, it eats the cam lobe within minutes. By the time most owners pull the valve covers, a new cam is mandatory. This is why an MDS-only lifter job rarely succeeds - the cam is already done.
Run free diagnosis →The oil-to-coolant heat exchanger sits in the valley and leaks oil into the coolant or coolant into the oil. Easy to confuse with a head gasket on a Hemi. Replace the cooler and gaskets together.
Run free diagnosis →If you keep driving after the tick starts, metal from the wiped cam circulates through the engine. At that point you're looking at a long block, not just a cam swap.
Run free diagnosis →The MDS solenoids in the valley can fail electrically, throwing P3400-series codes. Sometimes a precursor to lifter trouble, sometimes just a stuck solenoid.
Run free diagnosis →Run a free AI diagnosis tailored to your exact vehicle. Get the most likely cause and repair estimate in under 30 seconds.
Run a Free Diagnosis on My Hemi 5.7L100% free · No signup needed · Powered by NHTSA + AI
2009-2014 Ram 1500, Charger, Challenger, Grand Cherokee, and Durango with the 5.7L Hemi - these are the highest-failure-rate years for MDS lifter collapse.
2018+ models still use MDS, but build quality and oil control improved. Non-MDS variants (HD trucks, some fleet motors) avoid the issue entirely. An aftermarket MDS delete tune + non-MDS lifters effectively eliminates the failure mode.
Cam + lifter job at an independent shop runs $3,000-$4,500. Dealer pricing $4,500-$6,000+. If you're doing it anyway, most owners add an MDS delete tune ($300-$500) and non-MDS lifters so it never happens again.
If your vehicle is throwing a check engine light, these are the codes most often associated with the problems above. Click any code for full diagnosis steps and typical repair costs.
2009-2014 are the worst, particularly Ram 1500s and Grand Cherokees. The failure can still happen on 2015-2020 models but is less frequent.
It dramatically reduces the risk. The collapsing lifter is the deactivating one - if MDS never engages, the lifter never cycles its locking pin. Combined with non-MDS lifters during a rebuild, it is essentially a permanent fix.
No. By the time a lifter fully collapses it has already worn the cam lobe. Replacing only the lifter on a worn cam guarantees a repeat failure within months.
Most failures cluster between 80,000 and 150,000 miles, but documented failures exist as early as 40,000 miles and as late as 200,000.
Yes, with eyes open. A clean 5.7 with documented oil changes and no tick is a great motor. Budget for an eventual MDS delete or be prepared for the cam job.