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Makes 🢒 Cadillac 🢒 1999 🢒 Eldorado 🢒 Bulletins 🢒 4.6L LD8 , L37 Engines Oil Consumption Greater than 1 Qt. in 2,000 Miles - cylinder economy

4.6L LD8 , L37 Engines Oil Consumption Greater than 1 Qt. in 2,000 Miles - cylinder economy

Subject:4.6L LD8, L37 Engines Oil Consumption Greater Than 1 Qt. in 2,000 Miles

Models:.


When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

Condition/Concern:

Oil consumption greater than 1 quart in 2,000 miles on 96 -99 Cadillac Seville, Deville, Eldorado with 4.6L (LD8/L37) engines.

Recommendation/Instructions:

Be sure to note all the possible factors for oil consumption. Perform suggested checks and the oil economy test to determine if the engine is consuming more than 1 quart of oil in 2,000 miles.

Before performing the oil economy test on 4.6L Northstar engines:

    • Verify correct oil level on dip stick after oil change fill.
    • Verify the presence of the cam cover baffle through PCV hole.
    • Verify the PCV valve is functioning correctly. If the valve is in question, replace the PCV valve prior to the oil economy test.
    • Perform the 4.6L (LD8, L37) piston ring cleaning procedures in Bulletin 02-06-01-009.
    • An oil economy test should be performed after the cleaning process is completed. Before starting this test, the full oil level on the dip stick should be noted and shown to the customer. The correct oil fill is 7.1L (7 ½ qts) with a filter. The dipstick should not be read for least 15 minutes after the engine has been shut off for an accurate reading.
    • Verify when the vehicle returns after the oil economy test that the oil level is checked in the same exact manner in which the initial check was performed. If it is determined by the oil economy test that the engine is consuming more then 1 quart of oil in 1,000 miles, it is important that proper diagnosis be performed before any major engine disassembly. Perform the following additional checks/steps:
  1. Check misfire history counters if available. High counts indicate suspect cylinder.
  2. Check each bank heated oxygen sensor (h02s) for signs of oil burning, indicating suspect cylinder bank.
  3. Check for oil fouled spark plugs, indicating suspect cylinder.
  4. Perform cylinder compression tests dry, wet and leak down (listen for leak down at intake, exhaust, oil fill). Any cylinder compression or leak down numbers outside of the range of the other cylinders would indicate suspect cylinder.
  5. Remove intake and check for excessive oil present on back of intake valves, indicating valve guide scoring.
  6. Check valve guide seals.
  7. Check for missing/upside-down rings
  8. Check for possible ring end gap alignment.
  9. Check for cylinder wall irregularities.

SPECIAL NOTE: The 1996 through and including the 1999 service information manuals contain incorrect engine specification values. the service information manuals list values that are for production, and should not be used for service specifications.

THE CORRECT ENGINE SERVICE SPECIFICATIONS ARE AS FOLLOWS:

Cylinder bore diameter: 93 mm or 3.661 inches

Cylinder bore taper (MAXIMUM) is 0.100 mm or 0.004 inch.

Cylinder bore out of round (MAXIMUM) is 0.100 mm or 0.004 inch.

The piston to bore clearance @ 50 mm from top of piston (MAXIMUM) - 0.004 inch.

Now that you have completed the above diagnostics for an engine oil consumption with no trouble found, install the updated piston rings P/N 89017431. Note: This part number consists of a ring pack that only services ONE cylinder.

Special Note: The cylinder walls should inspected for any damage. The cylinder walls do not require any surface conditioning. (no honing necessary). Also the 2nd ring should be installed with the notch side down in the cylinder bore and finally, be sure to use the reduced cylinder head bolt torques when reassembling the 96 -99 4.6L (LD8/L37) engine.

THE REVISED PROCEDURE TO COMPLETE THE HEAD BOLT TORQUE SPECIFICATION IS AS FOLLOWS:

1. Tighten the cylinder head bolts in the sequence shown in SI.

A. First Pass: Tighten. Tighten the cylinder head bolts to 40N·m(30 lb ft) in the sequence shown in SI.

B. Second Pass: Tighten. Using the J 36660A , tighten the cylinder head bolts an additional 70 degrees in the sequence shown in SI.

C. Third Pass: Tighten. Repeat the sequence turning each bolt another 60 degrees.

D. Final Pass: Tighten. Repeat the sequence again turning each bolt a final 45 degrees (total 175 degrees).

Summary : The new specification is a total of 40N·m(30 lb ft) and then 175 degrees. This is 15 degrees less on the final pass than what is currently in the Service Manual. That makes the final pass 45 degrees instead of 60 degrees.

Please follow this diagnosis 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. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.

Models:

(96, 97, 98, 99 Cadillac Deville, 4.6L LD8 Engine) and (96, 97, 98, 99 Cadillac Eldorado, 4.6L LD8, L37 Engine) and (96, 97, 98, 99 Cadillac Seville 4.6L LD8, L37 Engine)