Being the world’s largest Dodge Challenger car club with hundreds and hundreds of club members, it should come as no surprise that West Coast Challengers is often the first to discover a flaw or a problem in the Dodge Challenger. Most are seemingly innocuous, and some problems have been pointed out to Chrysler executives and fixed in the next model year, such as the sheet metal crease marks in the trunk lid in early Challenger models. But some problems, like the timing chain failures in the Dodge Challenger, caused us real concern — and it all began right here.
Club member Terrence (Rattler249) was ground zero. Often driving hours to attend club events, his car suffered a timing chain failure early on. It was the dealership’s attempt to wrongfully void the warranty on Terrence’s car and deny the warranty repair that brought the club into this matter.
Having built more than a few engines in my day and having raced cars for many years, I had seen only one timing chain failure in my life. That’s not to say that it doesn’t happen, just that it is so rare of an occurrence that it immediately sends up a red flag, especially when it happens to our modern Dodge Challengers with relatively low miles on them.
The way most cars are designed nowadays, a timing chain failure will, in all likelihood, cause a catastrophic engine failure. The major damage occurs when the timing chain driven cam stops turning mid-stride leaving some valves open only to meet a rising piston. The resulting crash causes the valves to bend, and damaging both the valve guides and the tops of the pistons. At a minimum, new heads would be required as well as new pistons. The same could be said of vehicles equipped with timing belts which have an even shorter life span.
So, what’s the problem exactly? As outlined below, we are of the opinion that on the Dodge Challenger R/T which is equipped with the 5.7L Hemi engine and includes the MDS fuel savings feature when mated to the automatic transmission, causes such a harmonic disturbance within the engine that is enough to cause a catastrophic engine failure.
What is the basis for our opinion? Below is the road traveled, the road blocks and pot holes that we encountered, and the facts that became known to us by virtue of a constant vigil and monitoring of the problem.
After Terrence’s timing chain failure, his sister, who works at a GM dealership, mentioned that they had heard stories of timing chain failures in Chrysler vehicles. We did an Internet search and learned that pre-2009 5.7L engines had some problems with timing chain failures that were a direct result of the timing chain tensioner failing. The solution then, was to switch to the 6.1L’s beefier timing chain tensioner. However, in 2009, the 5.7L engine was completely redesigned and not equipped with the same timing chain tensioner and the 6.1L’s tensioner wouldn’t work in our cars, which didn’t get us any closer to finding a solution or solving the mystery but did help us rule some things out. i.e., that all of the pre-2009 timing chain failures were completely unrelated to our current problem.
We decided to start a thread on a Dodge Challenger specific forum and outlined the problem and inquired if anyone else had suffered a timing chain failure. That thread immediately went south as both Chrysler dealerships and technicians all claimed a cry of wolf, some belligerently doing so. To our credit, we kept the thread alive and began listing the timing chain failures as they came in. See list of failures below. That list began with one report a month and quickly progressed into several reports a month as fellow Dodge Challenger owners discovered this article or that thread by searching the Internet for the problem, apparently as dumbfounded as we were at having suffered a timing chain failure.
Many concerned owners called their local dealerships to inquire about the timing chain problem as others telephoned Chrysler through their toll free customer service number. All were met with canned responses and claims that this is the first time that they have ever heard of such an issue. Letters or emails sent to Chrysler about the issue got a similar canned response back along the lines of “Thank you contacting us, we value you as a customer.”
Monitoring many LX and Chrysler related forums, we discovered that the problem seemed isolated to the Dodge Challengers that were equipped with 5.7L Hemi engines and automatic transmissions, and was not affecting the equally equipped Dodge Charger, Chrysler 300 or Ram truck. Similarly, we discovered that the 3.5L and 6.1L engines were not suffering from the same timing chain failure. We also discovered that the 5.7L Hemi Challengers equipped with the 6-speed manual transmissions were likewise not affected. So almost right away, we knew that this problem was unique and isolated to the Dodge Challengers equipped with the 5.7L Hemi engine when mated to the automatic transmission.
An immediate assumption would be, and was made by many, that a bad batch of timing chains came down the pipeline. However, the timing chain failures were across several model years, so we ruled that possibility out almost immediately.
We next looked into the strength of the timing chain itself and were surprised to learn that our modern Dodge Challengers are equipped with a timing chain that is not much larger than a Schwinn bicycle. See comparison chart below. But even then, it appeared to be able to handle the job, although its size made more than a few owners a little bit edgy and uncomfortable.
We also learned early on, that simply replacing the stock timing chain with a beefier aftermarket timing chain could not be done on our modern Dodge Challengers because the thicker timing chains would not clear the timing chain cover without modifications, which would be frowned upon by Chrysler and jeopardize our vehicle warranty. While some might be interested in that modification, most are not. Even then, it got us no closer to finding answers.
Here, we have the timing chain failing, but why? Did the timing chain fail first and then, while whipping around, break the timing chain guide? Or did the timing chain guide fail, letting the timing chain free to break? It’s the old adage, Which came first, the chicken or the egg? In every instance of a failure, both the timing chain and the guide were found to be broken. To an owner, it doesn’t much matter which broke first, the resulting damage is exactly the same. Some owners took a preventative approach and decided to replace the timing chain, tensioner and guide in their cars only to discover all appeared to be completely normal and no signs of anything unusual. From this, we deduced that this isn’t a problem that happens over time due to stress or simple wear and tear but rather happens quite quickly and matter-of-factly, as even newly replaced timing chains and tensioners have failed with only a few thousand miles on them.
Another interesting discovery that was made was, the fact that not a single instance of a timing chain failure had occurred while the vehicle was using the AutoStick feature in manual mode. Quickly, we began advising club members and others to drive only in the manual AutoStick mode when traveling on the highway. This, in essence, would not allow the MDS feature to engage. The MDS fuel saving feature stops four of the cylinders from firing when the car is cruising and not under load. When engaged, a slight vibration can be felt in the car and the tone of the engine changes. By a simple process of elimination, we identified MDS as being at least partially responsible for the timing chain failures. The downside to driving in manual mode when on the highway and saving the engine this way was that with the MDS fuel saving feature disabled, fuel consumption increased sharply.
As the list of timing chain failures grew and hundreds of thousands page views later, the nay sayers were hushed by the overwhelming evidence of a problem existing. Literally, hundreds of similar forum threads began popping up all over the Internet as well, created by those, some once nay sayers themselves, who now wanted to capitalize on the problem’s popularity. Then began the wild theories as to what was causing the failures as gearheads from all across the country, now believers, chimed in with their own theories as to the cause. The original thread had grown so large in size, that many theories were simply repeats of past theories as no one really wanted to take the time to read through the thousands of posts already made. To curb this, we added a list of things ruled out so far as well as things known and that seemed to stem the tide a bit.
The things in common when the timing chain breaks so far are:
1. MDS is activated (auto trans., so 6-speed are excluded)
2. Traveling at freeway speeds (or coming off of freeway)
3. 2009-2011 model years affected so far.
4. Limited to the 5.7L motor so far
5. Dodge Challenger only
Things ruled out thus far:
A. 6-speed manual transmissions not affected
B. Other 5.7L vehicles not affected, i.e., Charger, 300, Ram truck
C. New guide shoe (white color) has also failed
D. New crate motor has also failed
E. Both stock and mod cars affected
F. Both stock tune and Predator tune (with MDS turned on) affected
G. All oil change intervals affected, i.e., 3,000 miles, 5,000 miles, etc.
H. All types of oil affected, i.e., both synthetic and conventional oil
Armed with these discoveries and the data collected so far, and with failure reports coming in regularly now as the problem seemingly grew, we asked ourselves the simple question: What was different in the Dodge Challenger versus the unaffected Dodge Charger, Chrysler 300 or Ram truck? Size became readily apparent. And when asked how size could make a difference, harmonics is immediately suspected. Harmonics would also explain why the 6-speed equipped Dodge Challengers with the same exact 5.7L Hemi engines were not being affected as they cruise in a different RPM range than the 5-speed automatics and do not have the MDS fuel saving feature. Further, if either or both the timing chains or the timing chain guides were bad, as some suspected, then the 6-speed Challengers, as well as the Dodge Chargers, Chrysler 300’s and the Ram trucks, would also be affected, yet they weren’t.
Having ruled out many things over the course of many months, with a special thanks to all of those who contacted us and shared their stories of failures and repair experiences, the only fact left standing that could not be explained away or ruled out, was harmonics.
Just as one might fill a wine glass with more or less liquid to create different sound when a finger is run around the rim, so too can the height, length, width and weight of a car make a difference in how its engine ultimately performs. Is the engine mounted too far forward or too far back? Is it mounted too much to the left or too much the right? Too high or too low? Are the mounting points to the chassis misplaced? All of these things can affect the harmonics of the engine, and in extreme cases, cause it to fail.
You obviously did not come here for a physics lesson but it is important to understand the science behind resonance and harmonics to understand why we zeroed in on it as the underlying cause, so we’ll keep this brief and very generalized. In a nutshell, every material on earth has a natural frequency at which it vibrates. This is called “resonance.” When that natural frequency or resonance is doubled, it is referred to as “harmonics,” e.g., first harmonic (two times the natural frequency), second harmonic (three times the natural frequency), etc. Each harmonic carries with it, some degree of energy, and when that energy is added to resonance it forces a vibration. If done to an exact and matching degree, the built up energy can cause the material to vibrate to the point of failure, much in the same way as an opera singer can cause a glass to shatter with just their voice if done in a precise pitch.
Seeing this effect in action speaks much louder than words, and probably the best example would be the Tacoma Narrows Bridge in which resonance was partially responsible for its failure. In 1940, just four short months after the bridge was completed, it collapsed. The bridge encountered Gale force winds that matched the natural frequency of the steel enough to excite the molecules and, well, watch for yourself in disbelief as the bridge’s steel beams appear to simply turn into rubber before failing …
Another demonstration of resonance can be seen in the below video where three Single Degree of Freedom (SDOF) systems are placed on a shaking table. As the frequency is increased, each system vibrates, almost uncontrollably, when its natural frequency is matched, appearing to turn once solid matter into rubber.
What we also discovered was that in all of the timing chain failure reports that we received, all had occurred while the vehicle was on the highway when the failure occurred, and that all were traveling within a certain RPM range, roughly between 2300 to 2500 RPMs. What this lead us to believe is that, in between that range, and while MDS is engaged, the timing chain components reached their natural frequency and harmonics lead to the inevitable failure of the components and ultimate demise of the engine. Whether the timing chain itself reaches its frequency threshold that causes it to fail or whether the timing chain guide reaches its frequency threshold is not known nor do we believe that it will ever be known without some very expensive and very lengthy scientific testing, which is almost meaningless when the after effects of both are already known and are exactly the same. We also don’t believe that Chrysler could have foreseen how the engine or its components would act when faced with such a precise and destructive force. The odds of all components coming together to produce the exact frequency to cause the failure must be infinitesimal.
To evidence this even further, driving the car in AutoStick mode, which disengages the MDS feature, changes the frequency being produced by the engine itself. However, once MDS is activated and the engine reaches the natural frequency of its components, which lies somewhere between the 2300 and 2500 RPM range, and that precise status is held for a sustained for a period of time, a failure is inevitable regardless of how new or old the timing chain or guide is. The only way to prevent this from happening is to change the substance of one or more of the parts which comprise the timing chain assembly, i.e., rather than using ABS or nylon switch to carbon-fiber or metal, rather than using steel switch to aluminum, etc. By changing the substance of a component, you change the frequency at which it is affected, and thus diminishing or eliminating altogether the resonance failure point at highway speeds, which is the only point in time where the car is maintaining an exact status for a length of time.
It should be noted, that we do not claim to be scientists. We are simply Dodge Challenger enthusiasts who know that common sense dictates that timing chains are not suppose break with only 30,000 to 40,000 miles on the odometer. We could be entirely wrong in our opinion, that a harmonic disturbance within the engine is the cause of the timing chain failures. However, based on our research, collection of data, conversations with affected owners and using common sense and the process of elimination as outlined above, we are confident in our opinion and know that the simplest answer, with the least amount of presumptions, is usually the correct answer.
Known instances of the timing chain breaking on the 5.7L Dodge Challenger:
1. 06/27/2011 — mileage not mentioned — … come to find out the timing chain broke …
2. 07/19/2011 — 85,000 miles — … and the timing chain broke…
3. 09/27/2011 — 33,385 miles — 2009 R/T Motor Broke
4. 11/23/2011 — 38,000 miles — Club member’s car. Broken timing chain. Car in shop for over two months.
5. 12/07/2011 — 34,000 miles — I found this thread the hard way…
6. 12/19/2011 — 22,600 miles — 2010 Challenger – Timing Chain Breaks…
7. 01/21/2012 — 60,000 miles — Engine went……….
8. 02/02/2012 — 38,000 miles — 2009 Challenger R/T lost a second motor .. (Second occurrence. See #3 above. 4,000 miles on new motor).
9. 03/08/2012 — 50,000 miles — BLOWN ENGINE 50,000 miles
10. 03/23/2012 — 14,000 miles — … my timing chain snapped
11. 04/04/2012 — 53,500 miles — My timing chain just broke today …
12. 04/16/2012 — 46,000 miles — Mine is in the shop with a broken timing chain…
13. 04/27/2012 — 31,000 miles — My chain broke back in December of 2011 …
14. 05/22/2012 — 37,000 miles — Here’s another 2010 Auto R/T with a broken timing chain! …
15. 06/13/2012 — 40,257 miles — I too have a broken timing chain …
16. 06/23/2012 — 38,485 miles — Guess I can be added to the list …
17. 06/26/2012 — 38,500 miles — Just happened last Saturday …
18. 08/02/2012 — 59,134 miles — … all of a sudden Bam the engine shuts down
19. 08/03/2012 — 38,000 miles — I had this happen at 38000 miles, 2010 R/T Auto
20. 08/08/2012 — 27,000 miles — The timing chain on my 2010 R/T just broke …
21. 08/10/2012 — 59,300 miles — … timing chain broke again. (Third occurrence. See #3 and #8 above. 16,000 miles on new motor).
22. 08/10/2012 — 63,000 miles — … timing chain broke cruising at 70mph on the highway
23. 09/03/2012 — 40,000 miles — … while driving to dallas my timing chain broke
24. 09/11/2012 — 24,000 miles — Welp – chalk up another one … (first 2011 to be reported here)
25. 09/21/2012 — 31,100 miles — This just happened a few days ago …
26. 10/10/2012 — 42,559 miles — Well it’s looking like I’m the latest timing chain victim …
27. 10/24/2012 — 65,000 miles — … driving on the highway 65MPH and “Pop goes to weasel”
28. 11/18/2012 — 40,000 miles — Mine just broke…2010 mopar 10, no mods, auto …
29. 11/19/2012 — 39,000 miles — just got another 2010 with 39000 in today …
30. 12/04/2012 — 40,000 miles — The timing chain on my 2010 Auto RT broke last Friday …
31. 12/09/2012 — miles pending — … R/T not running at the moment timing chain broke …
32. 12/11/2012 — 27,000 miles — … cruising on the interstate at 70, MDS on, when suddenly loss of power …
33. 01/03/2013 — 58,000 miles — … the dealer has confirmed that I did have a timing chain failure.
34. 01/22/2013 — 40,000 miles — It has been confirmed I as well did have a broken timing chain
35. 01/22/2013 — 43,000 miles — 2010 R/T, 5-speed auto with MDS. No mods at all.
36. 02/22/2013 — 52,000 miles — … it happen to me this weekend …
37. 04/15/2013 — 55,000 miles — I have now become victim to a failed timing chain
38. 04/20/2013 — 73,000 miles — cruising at 65 mph, in MSD, engine ‘shut down’
39. 05/13/2013 — 66,000 miles — lost it on the interstate doing 73 in MDS
40. 05/20/2013 — 56.616 miles — … on the freeway headed to work in the rain and Wham
41. 05/24/2013 — 28,000 miles — the chain went on the highway at 70+ mph
42. 06/07/2013 — 88,256 miles — … driving down the highway heard a loud pop …
43. 07/01/2013 — 52,000 miles — Timing chain broke on freeway …
44. 07/23/2013 — 54,057 miles — Was in a canyon going uphill at about 55mph …
45. 07/26/2013 — 49,000 miles — Cruising along 65 mph engine stalled.
46. 08/10/2013 — 22,281 miles — I wish I found this topic sooner
47. 09/17/2013 — 40,091 miles — driving 74 mph in cruse control just died …
48. 10/04/2013 — 68,000 miles — Add another one to the list OMG.
49. 10/22/2013 — 89,000 miles — Timing chain went on my 09 Challenger
50. 11/13/2013 — 55,320 miles — I had hoped I would never be posting this message …
51. 11/13/2013 — 42,342 miles — Just got up to highway speed Bam Powerloss …
52. 11/21/2013 — 53,000 miles — Add me to the list of failures …
53. 11/27/2013 — 73,000 miles — I was cruising at highway speeds (70 mph), in MDS
54. 02/12/2014 — Manufacturer recall initiated.
Update 02/12/2014 – Chrysler Recall Initiated:
“The engine timing chain guide on your vehicle may fracture. A fractured engine timing chain guide could cause the engine timing chain to break. A broken engine timing chain will result in severe engine damage.”
See: Recall Notice.
To find out if your Dodge Challenger is part of this or other recalls, you can visit the Mopar Owner Connect website and enter your car’s VIN number to get recall information specific to your Challenger.
Note: This recall includes all models equipped with the 5.7L Hemi engine and an automatic transmission, while we have determined that the Dodger Charger, Chrysler 300 and Ram trucks were not affected by the harmonic disturbance and any timing chain failure in those models, in our opinion, are deemed to be merely coincidental, minute and certainly not on the scale identified by us with the Dodge Challenger.