EI08221 - 3.9L, LZ9, LZE, LZ4, LZ8 Engine Oil Leak at Front or Rear of Engine (Engineering Information)

Some customers may comment on a oil leak coming from the engine.

GM Engineering has noticed an increase in replacements of the engine oil pan gasket. Engineering would like to better understand what is causing oil pan gaskets to be replaced. If a customer brings their vehicle in for a complaint of an engine oil leak, complete the following diagnostic steps, noting all information on the repair order:

1. Verify that the VIN and mileage are accurately recorded on the repair order.
2. What is the remaining oil life?
3. How did the customer notice the concern (i.e. was informed at time of oil change, noticed spots on driveway/garage, etc.)?
4. Describe the location on the engine in which the concern is noticed and the extent of the leak (seepage or oil dripping) If possible, take a digital picture of the area of concern.

Important: If the engine oil life is less than 25%, it will be necessary to change the oil before adding dye.

5. Add fluorescent dye to the engine oil. Completely clean the oil pan and surrounding area.
6. Run the vehicle for a minimum of 20 minutes to circulate the dye through the system.
7. Use the J 28428-E or equivalent (Black Light and Dye Method) to identify the source of the leak.

Important: If the leak is originating at the rear of the engine, the transmission and flywheel will need to be pulled in order to determine the exact origin of the leak.

If the leak is originating at the front of the engine, the crankshaft balancer will need to be removed to determine the exact origin of the leak.
8. If the leak is not yet visible, the vehicle should be driven for a minimum of 40-80 km (25-50 mi). Diagnose the source of the leak.
9. Mark on the diagrams provided the exact location of the leak(s), including measurements and reference point information. If possible, take a digital photo of the leak location.
10. If the source of the leak is:

-	at the front or rear of the oil pan, proceed to Step 11.

-	all other engine locations, proceed to Step 12.

11. For leaks in the front or rear of oil pan only, mark the exact location of the origin of the leak on the pan using a paint pen.

Important: DO NOT remove the oil pan gasket separately and reposition it with the oil pan. Be extremely careful not to contaminate the oil pan gasket with the residual oil from the engine.

11.1.

Carefully remove the oil pan, making sure to keep the gasket with the pan during removal.

11.2.

Inspect the oil pan sealing surfaces on the engine and oil pan. Note the amount (size/thickness) and location of the RTV that may be seen on the sealing surfaces.

11.3.

Once the inspection is complete, contact engineer Christina Connor at 248-676-1792. If Christina is not available, leave a message with the following information. If Christina is unable to respond within one hour, proceed with Step 12.

-	Tech name, date and time of call.

-	Dealer name, dealer code and phone number

-	Complete VIN and repair order number

12. Repair the engine oil leak.

Important: Be sure the complete VIN, mileage and repair order number are listed on all documentation.

13. Fax the front and back of the completed repair order and a copy of the diagram(s) identifying the source of the leak to: 248-685-6140, Attention: Christina Connor

E-mail digital photos of the leak (within 24 hours of the vehicle being repaired) to: [email protected]

For vehicles repaired under warranty, use: