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So there can be a number of specific reasons a high stressed alloy material can fail. There could be an issue with casting or machining flaws in the base material that causes an increase in stresses and thus subject the rod material to fatigue - each stress cycle advances a crack until it fails catastrophically. Another failure mode can be related to the improper application of the rod bolts - improper torque can lead to too much displacement when the engine is loaded up. This can manifest into big end bearing failure or bolt failure. There could be an improper heat treatment on the rod and the rod just doesn't hold up to its decreased strength, ductility or toughness. I am willing to bet the met urge all lab and the mechanical engineers are burning the midnight oil to determine the failure modes and root causes.
It's good to finally see an official document that we can all refer too. Thanks Longfella81.
I checked my car against the list and it doesn't appear to be affected by either situation. Curious to know though as I was cross referencing my VIN, I see an 0 in a fairly important slot space in cross referencing both the suspension and the con rod issue. My VIN shows WP0CC2A80. Does anybody have any idea what that 0 in that particular VIN slot may indicate? Build location, PTS color, CXX option? Any thoughts?
Last edited by halfmonkey; 03-30-2021 at 09:25 PM.
So there can be a number of specific reasons a high stressed alloy material can fail. There could be an issue with casting or machining flaws in the base material that causes an increase in stresses and thus subject the rod material to fatigue - each stress cycle advances a crack until it fails catastrophically. Another failure mode can be related to the improper application of the rod bolts - improper torque can lead to too much displacement when the engine is loaded up. This can manifest into big end bearing failure or bolt failure. There could be an improper heat treatment on the rod and the rod just doesn't hold up to its decreased strength, ductility or toughness. I am willing to bet the met urge all lab and the mechanical engineers are burning the midnight oil to determine the failure modes and root causes.
Yes, I was aware of these. Still not sure how they determined that this failure mode is exclusive to this particular batch of con rods and that it is solely caused by their imperfect manufacture and not by a confluence of other factors (including bad design), as well. They could also be unsure about this but, of course, it wouldn't be in their interest to share. Yet another confirmation of the old adage to avoid buying the first iteration of any product lest you end up being a beta-tester on your own dime.
Hey, I am proud (originally planned to be) owner of the first VIN listed for the GTS! Yeah! Car was supposed to be delivered tomorrow. Got the call today that it is not happening now due to "a part issue which should be resolved shortly, maybe deliver next week after we get the part". I can confirm, RL knows more than the dealers on this one.
Forwarded the recall notice to the sales staff and asking what next steps will be. See what I can find out...
Yes, I was aware of these. Still not sure how they determined that this failure mode is exclusive to this particular batch of con rods and that it is solely caused by their imperfect manufacture and not by a confluence of other factors (including bad design), as well. They could also be unsure about this but, of course, it wouldn't be in their interest to share. Yet another confirmation of the old adage to avoid buying the first iteration of any product lest you end up being a beta-tester on your own dime.
Well...except these weren’t the first; perhaps near the last.
Oh I get S/N #1 failures - another story, another time. It is in the failure analysis process - start with metallurgy evaluation of both failed and unfailed parts. I wouldn’t be surprised that a quality check for something like hardness was wrong (maybe an improperly calibrated hardness gauge) Maybe the heat treat oven for the rods was controlled to the wrong temperature for the batch of rods. My experience with failures is that it always boils down to human error someone didn’t set up or monitor a process. They know its that batch because someone discovered what, when and how someone else made a mistake through a random quality confirmation or an actual failure. In that case they go back to the previous and subsequent batches and re-run quality tests and thus bracket the affected batches till they know the extend of substandard parts.
It's good to finally see an official document that we can all refer too. Thanks Longfella81.
I checked my car against the list and it doesn't appear to be affected by either situation. Curious to know though as I was cross referencing my VIN, I see an 0 in a fairly important slot space in cross referencing both the suspension and the con rod issue. My VIN shows WP0CC2A80. Does anybody have any idea what that 0 in that particular VIN slot may indicate? Build location, PTS color, CXX option? Any thoughts?
One possibility is that they will replace the engines with new ones, but then ship the bad engines back to the factory to be rebuilt/repaired and used in future cars.
I dont think that'd ever happen. Most likely they'll get rebuild and set aside for warranty claims, or future people off warranty blowing their engine (mazda did that with rotaries) or even tossed.
03-30-2021, 08:31 PM
I like this one
