PIP5163D

Bulletin No.: PIP5163D
Published date: 08/8/2018
Preliminary Information
PIP5163D Alleged Cylinders Out Of Round
Models
Brand:
All
Model:
All
Model Years:
2000 - 2019
VIN:
from
All
Engine:
to
All
All
Transmissions:
All
Supersession Statement
This PI was superseded to update Model Years. Please discard PIP5163C.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition / Concern
Suspecting an engine block of possible cylinder bore damage, scoring or out of round as the
possible cause of engine oil consumption, misfire, cylinder leakage or blow by.
NOTE: GM has not had an issue with cylinders being machined out of round for any engine
family in recent history.
The peak to valley spec for crosshatch is .65-2.8 microns. Any deviation and the crosshatch
will be gone.
Even if a cylinder is suspected of being oversize we can only confirm that by checking with
an air gauge at the engine plant.
Recommendations / Instructions
When inspecting the engine block to determine if the cylinder bores are good,
Look for the following:
1. Cylinder damage or scoring- the cylinder walls will contain grooves deep enough to catch
with a finger nail.
2. An out of round cylinder bore- will contain areas where the cross hatch is missing or
worn from different section of the cylinder bore. If there is crosshatch all the way around the
bore from top to bottom the cylinder bore is not out of round.
3. Dirt intrusion- If the filtering system has been compromised the engine will wear out very
quickly. You will find grit in the intake Runners and the cylinder bores will look lightly sand
blasted. The crosshatch will be faint and there will not be sharpness. At high mileage this
Should be an insurance claim if the air filtering system has been opened numerous times for
service in dusty climates.
4. Catalytic Converter failure- If a converter fails and the brick is broken, the dust can be
drawn back into the engine. A block showing this type of failure, will have bores that look to
be sand blasted. Back cylinders go first if caught early. Otherwise there will be no
Crosshatch and the engine will need to be replaced.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is
resolved without completing every step, the remaining steps do not need to be performed.
© 2018 General Motors. All Rights Reserved.