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Service bulletin FSB 386-009

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10083020
Published by NHTSA2016-10-20
Manufacturer's numberFSB 386-009
Manufacturer's date2015-05-11
NHTSA componentENGINE AND ENGINE COOLING

NHTSA's summary

COOLANT LEVEL SENSOR, REPLACEMENT. THE COOLANT LEVEL SENSOR (PART NUMBER 21257608) ON SOME MACK CABOVER TRUCKS BUILT BETWEEN 10/04/2008 AND 02/20/2015 MAY FAIL INTERNALLY. FAILURE OF THE SENSOR CAN CAUSE THE MALFUNCTION INDICATOR LIGHT (MIL) TO ILLUMINATE AND CAN CAUSE AN UNPLANNED STOP IN CASES WHERE THE ENGINE PARAMETER "ENGINE SHUTDOWN WITH LOW COOLANT" IS ENABLED.

The document

No address for NHTSA's copy can be built for this communication. Ask the dealer for it by the manufacturer's number.

Components

Engine

Vehicles listed
MACK LEU2009 to 2016
MACK LR2015, 2016
MACK MRU2009 to 2016

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Recalls for the same vehicles and component
15V7020002015-10-26. ENGINE AND ENGINE COOLING:ENGINE:OTHER FUEL TYPES:TURBO/SUPERCHARGER

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

Other bulletins for the same vehicles and component
CBR 820-9 2026012026-02-03. Service bulletin. CBR - Mack Chassis - Engine Brake Only Works With The Brake Pedal, No Function During Cruise. US07 And Newer Emissions, Model Year 2008 And Newer.
CBR 2171-11 2025112025-12-03. Service bulletin. CBR - Mack Temperature Sensor Troubleshooting Guide
CBR 170-8 2025052025-06-02. Service bulletin. Inactive Code P25AE00 Being Generated After A Hard Pull And A Momentary Drop In Engine Oil Pressure (Low Oil Pressure) (Possible Related Codes - SPN4811 , SPN 100 , PID 100)
CBR-561 2025032025-04-02. Service bulletin. If oil dilution is suspected refer to the applicable CBR solution below: ∙ CBR-659􀁡Mack Chassis - Oil Diluted With Fuel; Fuel In Oil, Diagnostic Information - All Emissions, All Model Years
CBR-997 2024112024-12-02. Service bulletin. Vehicles may present with oil leak coming from the clutch/flywheel housing and observation of burned clutch smell or clutch slipping. These symptoms can be mistaken as a crankshaft rear main seal leak, when the actual cause is the crankshaft adaptor O-ring.
CBR-561 2024082024-09-04. Service bulletin. CBR: 11L, 13L, And 16L Engine Oil Analysis Specifications - US10 And Newer Emissions
CBR-2139 2024052024-06-04. Service bulletin. CBR: Vehicles built with an 11 liter engine may experience a complaint of excessive fuel in the oil. It is possible that the source of the fuel is the rear fuel galley plug in the cylinder head. A new and improved fuel galley plug has been developed to resolve this issue.
EC0028M 2023122024-01-03. Service bulletin. Emissions Campaign: Mack Trucks has determined that certain 2014 - 2018 commercial model year CXU, GU, LEU, LR, MRU Vehicles require a replacement Diesel Particulate Filter (DPF) along with updated software.
CBR-2320 2023122024-01-03. Service bulletin. CBR: For vehicles equipped with an 11L engine, the plastic saddle bracket holding the a/c line on the left side of the engine may move excessively and rub the area where it secures the line.
M-258-014 2023092023-10-03. Service bulletin. TSB: Aftertreatment Diesel Exhaust Fluid (DEF) Tank, Level Sensor, Replacement