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[Federal Register Volume 90, Number 12 (Tuesday, January 21, 2025)]
[Notices]
[Pages 7238-7239]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-01351]

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

[Docket No. NHTSA-2025-003]

Denial of Motor Vehicle Defect Petition

AGENCY: National Highway Traffic Safety Administration (NHTSA), 
Department of Transportation.

ACTION: Defect Petition DP22-002 has been denied.

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SUMMARY: This notice sets forth the reasons for the denial of defect 
petition DP22-002, submitted on April 29, 2022, by Mr. Sergio 
Betancourt (the petitioner) to NHTSA's Office of Defects Investigation 
(ODI). The petition requests that the Agency investigate alleged 
``wrong-sized wrist pins'' in Mercedes-Benz vehicles equipped with the 
M274 engine (including the Metris minivan, GLC300, and C300). After 
conducting a technical review of the petitioner's submissions, 
information provided by Mercedes-Benz in response to the Agency's 
Information Request, and data within its own files, NHTSA has concluded 
that there is insufficient evidence to warrant further action at this 
time. Accordingly, the Agency has denied the petition.

FOR FURTHER INFORMATION CONTACT: Mr. Tariq Bond, Vehicle Defects 
Division--D, Office of Defects Investigation, NHTSA 1200 New Jersey 
Ave. SE, Washington, DC 20590. Email: [email protected]. Phone: (202) 
366-5472.

SUPPLEMENTARY INFORMATION: 

Introduction

    Interested persons may petition NHTSA requesting that the Agency 
initiate an investigation to determine whether a motor vehicle or an 
item of replacement equipment does not comply with an applicable motor 
vehicle safety standard or contains a defect that relates to motor 
vehicle safety. 49 U.S.C. 30162(a)(2); 49 CFR 552.1. Upon receipt of a 
properly filed petition, the Agency conducts a technical review of the 
petition, material submitted with the petition, and any additional 
information. 49 U.S.C. 30162(a)(2); 49 CFR 552.6. The technical review 
may consist solely of a review of information already in the possession 
of the Agency or it may include the collection of information from the 
motor vehicle manufacturer and/or other sources. After conducting the 
technical review and considering appropriate factors, which may 
include, but are not limited to, the nature of the complaint, 
allocation of Agency resources, Agency priorities, the likelihood of 
uncovering sufficient evidence to establish the existence of a defect, 
and the likelihood of success in any necessary enforcement litigation, 
the Agency will grant or deny the petition. See 49 U.S.C. 30162(a)(2); 
49 CFR 552.8.

Background Information

    On February 4, 2022, the petitioner filed a Vehicle Owner 
Questionnaire (VOQ) designated ODI 11450360 reporting that the 
petitioner's vehicle made a popping sound and began to lose power while 
driving on a freeway at 70 mph. Petitioner stated that as he applied 
more accelerator input, the vehicle began to shake violently and began 
to expel white smoke through its exhaust. The petitioner safely exited 
traffic and arranged for the vehicle to be towed to a Mercedes 
dealership, where it was determined that the vehicle had a cracked 
piston. The dealer gave the petitioner a repair estimate for engine 
removal and diagnosis of a cracked piston, along with several repair 
options that included replacement of the catalytic converter and oxygen 
sensors, the damaged piston, and, contingent on damage identified 
during the diagnostic inspection, replacement of all four pistons and 
an engine rebuild.
    On April 29, 2022, the petitioner submitted a petition requesting 
that the Agency initiate an investigation into alleged ``wrong-sized 
wrist pins'' in all Mercedes-Benz models equipped with a variation of 
the M274 engine. The petitioner cited Mercedes technical service 
bulletin (TSB) LI03.10-P-060916 as the basis for the wrist pin concern. 
The petition included the petitioner's vehicle repair estimate, the 
TSB, and screenshots of web forum statements from other Mercedes owners 
discussing either engine durability problems or the TSB.

TSB LI03.10-P-060916

    The first iteration of TSB LI03.10-P-060916 was released on 
February 27, 2015. The TSB was updated 16 additional times through 
January 30, 2019. The TSB addressed the following complaint condition: 
``Clattering/rattling or knocking noise from the crank assembly of the 
engine when cold at oil temperatures up to approx. 50[deg]C mostly 
heard on engine deceleration'' and listed the cause as under analysis. 
The TSB gave further instructions on the collection of information and 
discouraged the replacement of any components.
    TSB Version 4, issued on September 21, 2015, introduced engine 
build clean points (March 27, 2015 or April 20, 2015 depending on the 
engine plant); cause (unfavorable tolerance of the piston wrist pin 
resulting in enlarged end float of the connecting rod in the piston); 
and remedy (compare the complaint vehicle sound to an enclosed sound 
file under various operating conditions and then if verified, replace 
the pistons, connecting rods, and bearings, using updated pistons that 
include updated wrist pins).

Petitioner Vehicle History

    The petitioner's vehicle is a 2015 Mercedes C300 equipped with the 
M274 (LS) 4-cylinder 2.0L direct-injected/turbocharged engine fueled by 
91 Octane or higher gasoline. A synopsis of the petitioner's vehicle 
history leading up to the events prompting the petition is listed as 
follows:

------------------------------------------------------------------------
              Date                   Mileage            Action(s)
------------------------------------------------------------------------
 Apr 2015..............  ..............  Vehicle manufactured. .

[[Page 7239]]

 
 Sept 2015.............  ..............  Titled to Owner #1
 Mar 2016..............           3,065  TSB LI03.10-P-060916
                                                  performed: R&R 4
                                                  pistons and connecting
                                                  rods.
 Jan 2017..............           7,618  Vehicle service incl.
                                                  oil change.
 Apr 2017..............  ..............  Damage Report: Front;
                                                  Left; Rear; Minor to
                                                  Moderate.
 Nov 2017..............  ..............  Damage Report: Rear;
                                                  Minor.
 Dec 2017..............  ..............  Damage Report: Front;
                                                  Moderate/accident
                                                  reported.
 Mar 2018..............          16,409  Vehicle service incl.
                                                  oil change.
 Oct 2018..............          17,047  Titled to Owner #2.
 Nov 2018..............          17,746  Vehicle service--tire
                                                  pressure TPMS.
 Feb 2021..............          26,927  Vehicle service incl.
                                                  oil change.
 Feb 2021..............          27,140  Titled to Owner #3
                                                  (Petitioner).
 Aug 2021..............  ..............  Accident Reported (no
                                                  details available).
 Jan 2022..............          51,672  Engine issue while
                                                  driving.
------------------------------------------------------------------------

Alleged Defect and Scoping

    The piston wrist pin links the upper narrow end of the connecting 
rod to the piston via two holes in the piston skirt. Proper operation 
requires a precise enough fit to prevent vibration while allowing 
sufficient lubrication and clearance to permit smooth rotation relative 
to the piston as it reciprocates within the cylinder bore. Based on the 
latest version of the TSB, customers may complain of clattering, 
rattling, or knocking noises from the engine, particularly with cold 
engine oil temperatures upon deceleration. This condition is attributed 
to unfavorable piston-wrist pin tolerance, leading to ``enlarged end 
float.'' Technicians are instructed to compare complaint vehicle sounds 
to a reference sound file and, if they match, replace connecting rods, 
pistons, and bearings from a dedicated replacement kit. Mercedes has 
asserted that this condition will not cause mechanical engine damage 
(evidenced by a lack of any such engine damage caused by wrist pin 
issues in the subject vehicles).
    ODI focused its review on the petitioner's vehicle engine 
configuration, which also falls within the scope of the TSB: a MY 2015 
Mercedes C300 vehicle manufactured prior to May 2, 2015. The subject 
engine includes turbocharging, the requirement for 91 Octane fuel, and 
the inclusion of piston wrist pins coated with diamond-like carbon 
(DLC), whereas the M274 engine variant included in the Metris minivan 
(cited in the petition) lacks the DLC coated wrist pin forming the 
basis of the petitioner's concerns. Thus, ODI did not include Metris 
vehicles in its analysis.

ODI Analysis

    ODI searched its VOQ data for references to wrist pins, symptoms 
comparable to those reported by the petitioner, loss of motive power, 
and general engine complaints such as noise (safety and non-safety 
related). Out of the 86,112 MY 2015 C300 vehicles produced, ODI was 
able to identify 96 related VOQs submitted to NHTSA. These complaints 
did not include any confirmed cases of wrist pin(s) causing a loss of 
motive power without the ability to restart, including the VOQ 
submitted by the petitioner.
    Of the 96 VOQs, eight consumers cited ``wrist pins'' in their 
complaint narrative and only three of those eight VOQs alleged symptoms 
that could be interpreted as a reduction of motive power, similar to an 
operational limp mode or reduction in performance. These VOQs primarily 
referenced engine noises, and one claimed that the ``engine broke'' 
without specifically describing any safety-related details to associate 
that complaint with a loss of motive power. Two VOQs mentioned wrist 
pins without any explanation of symptoms. While some VOQs have shown 
evidence of general engine part failure, they are uncorrelated to any 
trend, and further, ODI was unable to verify that any of these alleged 
wrist pin issues led to engine failure.
    Finally, the petitioner's vehicle was included within these VOQs 
that mentioned wrist pins, but there was insufficient evidence to link 
any failure with wrist pins in the Petitioner's submissions, including 
repair records.
    Petitioner's VOQ (11450360) reported losing power and shaking while 
pushing the accelerator, and engine power loss while white smoke was 
emitted from the exhaust pipe. The description further states that the 
petitioner later took the vehicle to a service center and the engine 
was diagnosed with having a cracked piston and included an invoice from 
the service center. The VOQ further describes that the subject (wrist 
pin) TSB was discovered later and implied a correlation between the 
conditions covered by that bulletin and the cause of his vehicle's 
engine failure. However, the petitioner was evidently unaware that his 
vehicle's engine had already received all new wrist pins and pistons as 
per the TSB in March 2016, when the first owner of the vehicle 
completed the servicing recommended in TSB LI03.10-P-060916 (as shown 
above in the summary of the vehicle's service history).
    Analysis of VOQs and data received from Mercedes-Benz indicates no 
relationship between wrist pin repairs and engine failure or loss of 
motive power. Broader searches of both data sources for engine stalling 
related to engine durability were not identified.
    An additional search of a commercial vehicle repair and diagnostics 
database for engine stalling related to engine durability for the 2015 
Mercedes C300 revealed no wrist pin-related engine mechanical damage 
allegations of any kind.
    Based on the nature of wrist pin-related piston skirt wear and the 
absence of a field data trend showing an engine stalling condition 
linked to wrist pins in particular or broken pistons in general, ODI 
has determined that no formal investigation is warranted. Accordingly, 
the Agency is denying the petition. As with all potential motor vehicle 
safety risks, NHTSA will continue to review any new information or 
incidents as they are submitted to the Agency.
    Authority: 49 U.S.C. 30162(d); delegations of authority at CFR 
1.95(a) and part 501.\1\
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    \1\ The authority to determine whether to approve or deny defect 
petitions under 49 U.S.C. 30162(d) and 49 CFR part 552 has been 
further delegated to the Associate Administrator for Enforcement.

Eileen Sullivan,
Associate Administrator, Enforcement.
[FR Doc. 2025-01351 Filed 1-17-25; 8:45 am]
BILLING CODE 4910-59-P
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