# Service bulletin FSB 257\-004A

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.

- Type: Service bulletin
- NHTSA id: 10083629
- Published by NHTSA: 2016\-10\-27
- Manufacturer's number: FSB 257\-004A
- Manufacturer's date: 2016\-09\-07
- NHTSA component: ENGINE AND ENGINE COOLING

## NHTSA's summary

MACK TRUCKS HAS RECEIVED REPORTS FROM THE AFTERMARKET REGARDING OIL LEAKS AT THE CCV HOUSING INLET TUBE AND AT THE SPLIT LINE BETWEEN THE UPPER AND LOWER HOUSINGS ON CHASSIS BUILDS BETWEEN JANUARY 1, 2014 AND JANUARY 26, 2016 WITH MP7 ENGINES. IT HAS BEEN DETERMINED THAT THE O\-RING INSTALLED ON THE INLET TUBE IS THE SOURCE OF THE LEAK AND OIL MAY LEAK DOWN THE BACK OF THE HOUSING GIVING THE IMPRESSION THAT THE HOUSING SPLIT LINE IS ALSO LEAKING.

## 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

- 2015 to 2017 MACK CXU
- 2015 to 2017 MACK GU
- 2015 to 2016 MACK LEU
- 2015 to 2017 MACK LR
- 2015 to 2017 MACK MRU

## Recalls for the same vehicles and component

- [15V702000](/recalls/nhtsa/15V702000.md), 2015-10-26: ENGINE AND ENGINE COOLING:ENGINE:OTHER FUEL TYPES:TURBO/SUPERCHARGER

## Other bulletins for the same vehicles and component

- [CBR 820\-9 202601](/bulletins/11028051.md), 2026-02-03, Service bulletin: ENGINE; VEHICLE SPEED CONTROL. 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 2107\-22 202601](/bulletins/11028032.md), 2026-02-02, Service bulletin: ENGINE. CBR \- Mack DEF Level \(UQLS\) Sensor Troubleshooting Guide \- US17\+OBD16 Emissions to US22\+OBD2023 \(DOES NOT APPLY TO AN\(4\) and PR\(4\)\).
- [CBR 2171\-11 202511](/bulletins/11026025.md), 2025-12-03, Service bulletin: ENGINE; ELECTRICAL SYSTEM. CBR \- Mack Temperature Sensor Troubleshooting Guide
- [CBR 2107\-21 202505](/bulletins/11018813.md), 2025-06-02, Service bulletin: FUEL/PROPULSION SYSTEM; ENGINE. Mack DEF Level \(UQLS\) Sensor Troubleshooting Guide \- US17\+OBD16 Emissions and Newer
- [CBR 170\-8 202505](/bulletins/11018804.md), 2025-06-02, Service bulletin: ENGINE. 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 202503](/bulletins/11016342.md), 2025-04-02, Service bulletin: ENGINE. 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 202411](/bulletins/11010857.md), 2024-12-02, Service bulletin: ENGINE. 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 202408](/bulletins/11006925.md), 2024-09-04, Service bulletin: ENGINE. CBR: 11L, 13L, And 16L Engine Oil Analysis Specifications \- US10 And Newer Emissions
- [CBR\-2139 202405](/bulletins/11000831.md), 2024-06-04, Service bulletin: FUEL/PROPULSION SYSTEM; ENGINE. 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 202312](/bulletins/10248108.md), 2024-01-03, Service bulletin: ENGINE AND ENGINE COOLING; UNKNOWN OR OTHER. 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.

JSON: [/v1/bulletins/10083629](/v1/bulletins/10083629)

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