Dodge’s timing chain recall fix seems to have worked.
In June 2014, we published the accountof how we became aware of a defect with FCA’s (now Stellantis) 5.7-liter Hemi engine. Specifically, it concerned 5.7L Hemis installed in Dodge Chargers and Challengers between 2009 and 2014 in five-speed automaticequipped models with MDS, the fuel-saving cylinder deactivation feature. In that story, we detailed the failure of the 5.7L Hemi timing chain in the author’s wife’s 2011 Dodge Challenger R/T, which occurred without warning on Los Angeles’ I-10 interstate while in Eco fuel-saver mode.
Still under warranty and with only about 66,000 miles on the odometer, the Hemi’s timing chain, timing chain guide, and timing chain tensioner were replaced, as were all the valves and valve seals, which made momentary contact with their respective pistons during the failure. The repair work was done under Customer Satisfaction Notification P01, an FCA program just below the status of full-blown recall, which allows for service departments to repair customer-reported timing chain failures at no cost to the customer. These repairs were undertaken at a local Dodge service department in Moreno Valley, California, and while the car continued to have various electrical and cooling system issues over the years, the problem with the timing chain never recurred.
By early 2021, however, the 2011 Dodge Challenger R/T had experienced a cluster of unrelated problems, from stored trouble codes and warning lights to wiring harness, alternator, battery, keyless entry, and assorted electrical system maladies. Once over 200K miles, the engine began experiencing occasional overheating problems, a common issue for high-mileage cars. After an aborted attempt to fix the issue with K-Seal Head Gasket Repair, the author replaced the original radiator with a new unit from RockAuto.com.
At 235,000 miles, a head gasket failed. We reached out to Dodge, and thanks to our special relationship with the manufacturer, they sent us a new replacement 5.7L Hemi from their Mopar replacement parts division with the caveat that we deliver some ink on it. After having the original Hemi swapped out for the new replacement Hemi at the cost of $3,165 (for labor and associated parts, but not inclusive of the new Hemi long-block), we decided to autopsy the original engine long-block to gain intel for other Hemi owners out there.
Original 5.7L Hemi Timing Chain Failure
In this photo from 2014 of the original repair, the broken timing chain, timing chain tensioner (left), and timing chain guide (now in two pieces on the right) can be seen from the original repair session at 66,000 miles. Note how the two chain guide pieces were made of black plastic. They cracked into two when over-pressured by a spike in chain tension and were the focus of the “Customer Satisfaction Notification P01” campaign. The fix was replacing it with the uprated nylon-lined aluminum unit found in the 6.4L “Apache” Hemi; this is also the one that came in our new replacement 5.7L Hemi long-block.
Uprated 5.7L Hemi Timing Chain Guide
When our new replacement 5.7L Hemi arrived, our first order of business was to check out the timing chain and tensioner gear. The white arrow shows the newer, upgraded timing chain guide, which can be compared with the black plastic version that shattered into two pieces in the previous photo. The timing chain tensioner (on the passenger side of the timing chain) is still the original (2009 Eagle) design and type. The Mopar Parts replacement Hemi is a new engine, not a remanufactured one, and comes with a new windage tray and oil pan gasket set. DIY folks will need to reuse their valve covers, intake manifold, and all other external tin, or replace with new during the swap.
5.7L Hemi Teardown at IMM
To get answers on the fate of our original 5.7L Hemi, we turned to Indio Motor and Machine (IMM) in Indio, California, where technician Johnny Wadlund began the disassembly process. IMM is an expert in Mopar performance, and we’ve featured their work many times before (check out IMM’s previous build of a low-deck big-block wedge HERE, a budget-oriented Magnum 360 HERE, and a 620-hp LA-series small-block HERE). The idea was to carefully disassemble the 5.7, documenting all the wear and any obvious distress as we went along. Among the big questions we had were whether this was a core worth rebuilding and whether the prescribed warranty repairs worked.
5.7L Hemi Cylinder Head Rebuild
At the end of each cylinder head is this small green Mopar decal; both of our cylinder heads have this decal, but the serial number and the part number are different for each head. If you happen upon a junkyard or swap-meet 5.7L Hemi core that has this decal (hopefully, there’s one on each head), you’ll know that it’s been rebuilt, which will have an impact on its worth. A rebuilt head with this decal will have received at some point new valves, valve seats, springs, retainers, and locks. As these engines are also known to suffer from dropped valve seats (ours had not), the green decal can easily call out a fix in this trouble-prone area. As we later discovered, however, it can also be a harbinger of shoddy service department work.
5.7L Hemi Timing Chain Assembly
We’ll be returning to this area shortly, but we want to show you before disassembling the in situ timing chain, tensioner, and guide repairs made all those years and miles ago (approximately 169,000 miles and seven years prior). The chain was tight, and the timing chain tensioner and chain guide looked good. If this was an untouched 2011 5.7L Hemi, the chain guide would still be black plastic like the one on the right (just not broken in two pieces).
Signs of Thermal Stress
As Wadlund tore down the Hemi, we carefully noted the normal and the abnormal wear. Our first hint that this was a distressed engine was in comparing the passenger-side cylinder head combustion chambers (left) with the driver-side combustion chambers. While the driver’s side looks normal or even excellent for a high-mileage engine with 235K miles, the passenger-side is rife with carbon and other deposits (possibly coolant residue). These deposits are not consistent with cylinders controlled by MDS, leading us to believe the MDS was not involved; we suspect a head gasket failure. It’s important to note that the engine was running smoothly upon its last shutdown (despite several stored codes and a loss of coolant).
Does K-Seal Head Gasket Repair Really Work?
Over a year ago, we endeavored to answer the question, does K-Seal Head Gasket Repair really work? The plan was to try K-Seal in our Challenger R/T and KW Fiberlock in our 2005 Chrysler 300C—both of which had been suffering from coolant loss and overheating. (The temporary fix from the KW Fiberlock is still holding up in the Chrysler 300C a year later.) Just after applying the K-Seal product as advertised, the Challenger’s radiator tank split, bringing the test to a temporary halt. After replacing the radiator with a new one from RockAuto.com, we placed the Challenger back into service with a new load of water and antifreeze, but no additional K-Seal. The radiator failure did have the unintentional effect of thoroughly soaking all the wiring (as well as the alternator, relay box, and ABS control unit) directly behind the passenger-side radiator tank, which likely contributed to the many fault codes we experienced. These codes, coupled with an impending smog test, forced us to swap the engine for a new one late this past winter.
Driver-Side Gasket and Fire Deck
Looking once again for things out of the ordinary, we noticed that the passenger-side head gasket looked breached toward the front of the engine. The multilayer steel (MLS) gaskets used on the 5.7L Hemi do an excellent job of sealing relative to the fiber gaskets of years ago, but they can’t compensate for severe temperature differentials from one end to the other, nor can they make up for a previous shoddy job of surface cleaning. Note how the discoloration on the gasket surface gets more pronounced from left to right.
The Quickie Dealership Service Department Fix
We didn’t have to look far to find a culprit of the gasket failure; a quick clean-up of the cylinder head’s fire deck revealed that instead of having the cylinder heads sent out to a machine shop for resurfacing, the dealership that did the original timing chain warranty work in 2014 took a shortcut and used a Scotchbrite pad on a high-speed grinder to clean the gasket surface—a big no-no! Johnny’s finger points to a series of telltale witness marks from the errant operation. (At this point we had to ask ourselves if the gaskets were reused, as well.) We are a little surprised it lasted 169,000 miles, though all those miles were fraught with other issues on a continual basis.
Hemi MDS Lifter Inspection
We’ve heard lots of horror stories over the years regarding the lifters in Hemi engines featuring MDS, but other than some minor ticking, we’ve never experienced it in this high-mileage engine. We’re happy to report no lifter damage was found in either the standard cylinders (2, 3, 5, 8) or the MDS cylinders (1, 4, 6, 7). A common problem is for the locking pin in an MDS lifter to not engage or disengage from the plunger, often the result of using an oil viscosity heavier than the specified 5W30 synthetic. When this happens, the loose roller tappet hammers and bounces on the cam lobe at high speed when it’s supposed to be solidly engaged. The initial failure cascades until the needle bearings in the lifter cause the roller to lock up, at which time the affected cam lobe wears away. The valve seats and valves also pay a price when this happens.
5.7L Hemi Timing Chain Guide Wear
Just six photos ago, we showed you the original broken timing chain guide made of black plastic, which was broken in two and replaced in 2014. The piece Dodge replaced it with was this cast aluminum and nylon unit, lifted from the 6.4L Hemi. It’s important to note that even though this engine was built 11 years ago and repaired seven years ago, this Eagle-variant 5.7L Hemi with MDS is still being manufactured and installed in new R/T Challengers and R/T Chargers today. One of the differences is that these days the 5.7L comes with this uprated timing chain guide. Note that in the 169,000 intervening miles since being repaired, there is virtually no wear on this item. As for the factory’s fix for the original Hemi timing chain defect, we’d have to deem the engineering effort a success, despite the other unrelated (dealership-induced) problems we encountered.
Bent Camshaft VCT Dowel Pin
As IMM dug deeper into the 5.7L Hemi and removed the timing chain and variable camshaft timing (VCT) hub assembly, it was discovered that the dowel pin that locates the timing chain and VCT assembly was severely bent. This would’ve affected the valve timing events by slightly retarding everything, but probably not enough to notice. What’s interesting is that it never failed in the 169,000 miles since the timing chain was repaired at the dealership service department. We can’t say for sure this is installation error, but the odds are in favor. This is literally the lynchpin of the valvetrain; when this breaks, all hell breaks loose.
5.7L Hemi Camshaft Inspection
Do a web search for “Hemi camshaft failures,” and you’ll find a few thousand photos of gouged cam lobes, most of them the result of lifter failures on MDS cylinders. Because this author’s wife dutifully changed the full synthetic 5W30 oil every 5,000 miles over the Hemi’s 235,000-mile life (that’s about $4,000 worth of oil changes!), this bumpstick looks pristine for such a high-mileage unit. This one passes inspection and can go for another 100K miles. Folks, on an MDS-equipped Hemi, it’s vitally important to use the right oil and viscosity at the right change intervals. Not doing so risks contaminating the oil and blocking the lube circuit into or out of one of the MDS lifters, causing it to not lock or unlock the plunger. Higher viscosities than 5W30 also cause the plunger in the MDS lifter to delay the locking action until the lobe’s clearance ramp has ended and the lifter is on its way up, eliminating the important cushion provided by the plunger’s hydraulic lash.
5.7L Hemi Cam Bearing Wear
The news would only get better from here, with the cam bearings showing little wear. This is not so surprising, given the high level of manufacturing accuracy and precision employed in the manufacturing process of the 5.7L Hemi. We would see a repeat of this wherever the lube circuit was providing the factory-specified 5W30 full synthetic.
5.7L Hemi Bore Wear
One thing we surely didn’t expect on such a high-mileage engine is that it would have so little bore wear in its cylinders. This phenomenon has also been seen with other late-model electronic fuel-injected engine families where fuel wash on cold start-up is virtually nonexistent and a full synthetic is used throughout the engine’s life. The challenge for engineers in the 21st century is not stopping bore wear from occurring but trying to get sealing surfaces to break in and seal properly within the first 500 miles. Here you can see most of the original cross-hatching from the original factory boring job is still extant. This block doesn’t even need to see a boring machine again; a simple berry-brush hone is all that would be needed to address ring seal.
5.7L Hemi Main and Rod Bearing Wear
Once again, we were happy to see virtually no wear on any of the rod or main journal bearings on the 235,000-mile 5.7L Hemi. Again, this is a result of very tight factory tolerances, high-quality OE assembly, and the continuous use of 5W30 full synthetic. These bearings are made of aluminum and when new exhibit a surface of micro grooves to hold oil, which can still be seen in all the bearings taken out of this high-mileage Hemi. All the crankshaft journals showed no signs of wear, and had we not known the specifics of this engine we would’ve assumed it to be almost new.
5.7L Hemi Piston / Rod Assemblies
Much has been said over the years to malign the stock cast pistons of the 5.7L Hemi, but this photo proves they are well suited to the job they were assigned. The factory hypereutectic cast aluminum pistons are designed for minimal expansion over a wide thermal spectrum and feature press-fit pins in forged PM connecting rods with cracked caps. These can be reused with a new set of rings and bearings, but for performance use we recommend an upgrade to a forging with a full-floating pin as the hypereutectics will not withstand the heat of boost and the top ring is too close for comfort. IMM warns that you shouldn’t reuse stock rods if they need resizing; resizing eliminates the built-in one-of-a-kind match that cracked rods offer. The bearings and crank races looked so good, however, that with a new set of rings and bearings these piston/rod assemblies could be reused for another 100,000 miles.
Outside of some obvious stress where coolant blow-by entered the fire deck and combustion chambers on the passenger-side cylinder bank, the teardown revealed our 5.7L Hemi in surprisingly good shape. While it seemed to be running well enough at shut-down (outside of the coolant loss), there were no promises that we’d see so little wear. We were bummed about the sometimes shoddy work quality of the dealership service department that did the original repairs, but we chalk it up to it being rushed after enduring a significant wait for parts and long exposure to the elements outside while disassembled (three weeks during 2014 in our case). The good news is that this core is fresh enough to warrant a stock rebuild. If we can scrape up the cash, we may buy some rings, bearings, and fasteners; rebuild the cylinder heads (the right way this time); and screw it back together again to have a spare down the road.
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