Bulletin No.: PIP5487B
Published date: N/A

Preliminary Information
PIP5487B 6.6L L5P Duramax Coolant Leaks
Models
Brand:

Model:

Model Years:

VIN:
from

to

Engine:

Transmissions:

Chevrolet

Silverado

2017 - 2019

All

All

6.6 L5P

All

GMC

Sierra

2017 - 2019

All

All

6.6 L5P

All

Involved Region or
Country

North America

Additional Options
(RPO)

6.6 L5P

Condition

A customer may comment on a coolant leak, coolant consumption or
of a low coolant message being displayed on the Driver's Information
Center (DIC).
This may be due to cooling system leaks or an improper coolant fill
procedure.
It may take a few engine temperature cycles (from operating
temperature to cold) for the coolant level to show a lower than
normal level.

Cause

Be sure to complete the current SI coolant system leak checks and
verify there are no external leaks.
Reference the locations below to aid in locating external coolant
leaks.
If no external leaks are found, refill the cooling system following SI
procedures for filling the cooling system.
Evaluate coolant levels after a proper coolant fill is completed.

Correction:
If the diagnosis has lead to external coolant leaks or a coolant loss concern check for leaks in the following areas:

Welded flange leaking on the Exhaust Gas Recirculation (EGR) coolant return pipe. Refer to
call out #1 in the above picture.

Welded flange leaking on the Exhaust Gas Recirculation (EGR) coolant feed pipe. Refer to call
out #2 in the above picture.

Another view of the leaking welded flange on the Exhaust Gas Recirculation (EGR) coolant
feed pipe. Refer to call out #2 in the above picture.

Coolant leak at the O-ring seal of the Exhaust Gas Recirculation (EGR) coolant feed pipe.
Refer to call out #2 in the above picture.

View of a rolled or pinched O-ring at Exhaust Gas Recirculation (EGR) coolant feed pipe.
Refer to call out #2 in the above picture.
NOTE : The leak shown above could only be confirmed after removing the front accessory
drive bracket and alternator.

Coolant leaking from coolant hoses at the Emission Reduction Fluid Injector (DEF Injector).
Please be aware of the following if there is a need to pressure test the cooling system:
Note: The radiator surge tank uses two different radiator surge tank caps. The radiator surge
tank cap that vents pressure in the event of excessive cooling system pressure is located on
the lower outboard side of the radiator surge tank (2). The radiator surge tank cap that is
located on top of the radiator surge tank (1) is where the cooling system is filled and where
pressure testing equipment is to be mounted.
Caution: The cap mounted to the top of the surge tank uses LEFT HAND threads. Turn the cap
clockwise to remove the cap or counter clockwise to install the cap. Failure to turn the cap in
the proper direction when installing or removing it may cause damage to the cap and/or the
surge tank.
Refer to Cooling System Leak Testing (L5P) for more information.

Version History
Version
Modi ed

3
Created on 03/13/2017
9/6/2017 to add 2018 model year
07/25/2018 to add 2019 Model Year

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