Key Takeaways
- 5.7 Hemi splits into 2003-2008 and 2009-on Eagle head generations
- MDS lifter failure is the specific thing to check on any used Hemi
- Take the complete accessory drive as an assembly, not individual brackets
- Broken exhaust manifold bolts are normal on these. Budget for it
Engines by generation
| Engine | Years | Notes |
|---|---|---|
| 3.7 V6 | 2002-2012 | Base engine, low demand, cheap |
| 4.7 V8 | 1999-2013 | Two versions, early and later high-output |
| 5.7 Hemi, early | 2003-2008 | Original heads, MDS from 2006 on some |
| 5.7 Hemi, Eagle | 2009 on | New heads, VVT, revised intake |
| 3.6 Pentastar | 2011 on | Shared across the Chrysler range |
| 3.0 EcoDiesel | 2014-2019, 2020 on | Limited supply, specialised |
The Hemi split
The dividing line is 2009. The Eagle head engines changed cylinder heads, intake manifold, and added variable valve timing. The two generations share a block architecture and bellhousing, so a swap is mechanically feasible, but the electronics and the intake are not interchangeable.
Practically: match generation to generation. If you are putting an Eagle engine into an early truck you need its intake, sensors and a controller that expects VVT, and at that point you are doing a swap rather than a replacement.
Within a generation, the Hemi appears across RAM, Durango, Grand Cherokee, Charger, Challenger and 300. That breadth is genuinely useful in a yard, though car and truck applications differ in oil pan, accessory drive and exhaust manifolds.
MDS, and why people delete it
Multi Displacement System shuts down four cylinders under light load to save fuel. It works through special collapsing lifters controlled by solenoids in the lifter valley.
The known problem is those lifters. When one fails it produces a persistent tick, and a failed lifter roller can damage the camshaft lobe beneath it. Repair means pulling the intake and heads, so it is not a small job.
For a used engine purchase this is the specific thing to investigate. Ask whether the engine ran quietly. If you can pull a valve cover, look for a rocker sitting at a different height from its neighbours. Metal in the oil is a hard stop.
Many rebuilders delete MDS entirely, fitting standard lifters and a non-MDS camshaft with a matching tune. If you are buying a rebuilt engine, that is a reasonable specification rather than a red flag.
What has to match
- Generation, as above.
- Accessory drive as a complete assembly. Truck and car layouts place the alternator, AC compressor and power steering differently, with different brackets and belt routing.
- Oil pan and pickup, which differ between truck, SUV and car applications and decide crossmember clearance.
- Exhaust manifolds, which differ by application and are frequently cracked anyway.
- Flexplate, matched to the transmission.
- MDS or non-MDS matched to the controller calibration.
- Engine harness and PCM taken together from the donor where possible.
Inspecting a used one
- Turn it by hand two full revolutions. Even resistance throughout.
- Check oil and coolant at the caps for cross-contamination.
- Look at the exhaust manifold bolts. Broken studs are routine on these engines. Not a dealbreaker, but budget an extractor and time.
- Pull a valve cover if the yard allows. Even rocker height and no varnish is what you want.
- Check the donor's mileage if the cluster reads, and its reason for scrapping.
- Look for evidence of overheating at the head-to-block joint and in the coolant passages.
The 3.6 Pentastar
Worth a separate note because it is now common in yards and interchanges very widely across the Chrysler range, appearing in RAM, Wrangler, Grand Cherokee, Charger, Journey and Town and Country.
The known issue on early versions, roughly 2011-2013, is cylinder head failure on the left bank, which produced a misfire and a ticking noise. Later heads revised the design. If you are buying an early Pentastar, check whether the heads were replaced under the extended coverage Chrysler offered, and treat a misfire history as a reason to look at a later donor instead.
Otherwise it is a durable engine with excellent parts availability, and the sheer number of applications means a yard without a RAM may still have a Grand Cherokee with the same engine.