GMC Yukon XL 2000–2006

▸FUEL SYSTEM, GASOLINE1

1. Manufacturer communication2000–2006 GMC YUKON XL ・ 2021-04-19(4 earlier editions of this document folded here)

   Engine Block Cylinder Bore Damage Information

   1. 1Fault

      • Leak
      • The block is suspected of cylinder bore damage, scoring or out of round as the cause of oil consumption, misfire, cylinder leakage or blow by.
      ↓→

   2. 2Finding the cause

      • Cylinder: defective
      • Engine Block: defective

      Possible causes

      • If a catalytic converter fails and the brick breaks, its dust can be drawn back into the engine.

      Steps to confirm (in the document’s order)

      1. The peak to valley spec for crosshatch is .65-2.8 microns; any deviation and the crosshatch will be gone.
      2. Cylinder damage or scoring: the walls have grooves deep enough to catch with a finger nail.
      3. If there is crosshatch all the way around the bore from top to bottom, the bore is not out of round.
      4. Dirt intrusion: with a compromised filtering system the bores look lightly sand blasted, and the crosshatch is faint with no sharpness.
      5. A block with this converter-dust failure has bores that look sand blasted.
      ↓→

   3. 3Correction

      Repair

      • If not caught early there will be no crosshatch and the engine will need to be replaced.

      Caution

      • GM has not had an issue with cylinders being machined out of round for any engine family in recent history.
   Read the sentences of the record

   From the manufacturer’s document

   • Applies to：Applies to all brands and models, model years 2000 - 2021.
   • Condition：The block is suspected of cylinder bore damage, scoring or out of round as the cause of oil consumption, misfire, cylinder leakage or blow by.
   • Caution：GM has not had an issue with cylinders being machined out of round for any engine family in recent history.
   • Confirm：The peak to valley spec for crosshatch is .65-2.8 microns; any deviation and the crosshatch will be gone.
   • Confirm：Cylinder damage or scoring: the walls have grooves deep enough to catch with a finger nail.
   • Confirm：If there is crosshatch all the way around the bore from top to bottom, the bore is not out of round.
   • Confirm：Dirt intrusion: with a compromised filtering system the bores look lightly sand blasted, and the crosshatch is faint with no sharpness.
   • Cause：If a catalytic converter fails and the brick breaks, its dust can be drawn back into the engine.
   • Confirm：A block with this converter-dust failure has bores that look sand blasted.
   • Repair：If not caught early there will be no crosshatch and the engine will need to be replaced.

   Open the manufacturer’s document (PDF) ↗ The points above were read from this document.

   Remedy

   This Preliminary Information communication provides information to the technician about 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. Technician will need to inspect the engine for Cylinder damage or scoring, An out of round cylinder bore, Dirt intrusion, and Catalytic Converter failure.