Grand AM L4-144 2.4L DOHC VIN T SFI (1997)
Idle Speed: All Technical Service Bulletins
Engine - Rough Idle/Miss/Cold Stall/High Oil Pressure
File In Section: 6 Engine
Bulletin No.: 77-61-09B
Date: October, 1997
Subject:
Engine Stall at Cold Start, Rough Idle, Oil Filter Expansion, High Oil Pressure, and P0300 DTCs
(Replace Oil Pump Cover Assembly)
Models:
1995-97 Buick Skylark
1995-97 Chevrolet Cavalier
1997 Chevrolet Malibu
1995-97 Oldsmobile Achieva
1995-97 Pontiac Sunfire, Grand Am
with 2.3L, 2.4L Engine (VINs D, T - RPOs LD2, LD9)
This bulletin is being revised to add a new Service Procedure and to revise the Service Parts ln1ormation. Please discard Corporate Bulletin Number
77-61-09A (Section 6 - Engine).
Condition
Some vehicles may exhibit one of a number of concerns related to this condition. The most common symptom will be stalling on initial cold starting,
followed by hard restarting. Other concerns may include oil filter canister expansion or leakage and high oil pressure when checked with a gauge. Some
vehicles may also exhibit Diagnostic Trouble Codes P0300, P0301, P0302, P0303, and P0304 indicating engine misfire conditions. Oil pressure at
operating temperature may exceed 827 kPa (120 psi).
Cause
Due to a condition of the relief valve and the relief valve bore, the relief valve may intermittently become stuck causing high oil pressure. The increased
oil pressure may cause the hydraulic valve lifters to raise the valves off of their seats creating a loss of compression and engine misfire or stalling on
initial start-up.
Diagnosis
If the vehicle exhibits any of the above conditions, install an oil pressure gauge calibrated to read at least 1034 kPa (150 psi) in the oil pressure port on
the intake camshaft carrier and observe oil pressure at 3000 RPM. The oil pressure, even in extreme cold, should not exceed 689 kPa (100 psi). With the
engine oil at operating temperature, oil pressure should not exceed 586 kPa (85 psi) at 3000 RPM.
Correction
If the oil pressure exceeds these limits, replace the Oil Pump Cover with an oil pump cover that has an improved pressure relief valve and pressure relief
valve bore.
Service Procedure
1.
Remove the Radiator Outlet Pipe and the Engine Oil Pan, using procedures outlined in Section 6A7 or the Engine Mechanical Section of the
appropriate Service Manual.
2.
Remove the Balance Shaft Drive Chain cover.
3.
Remove the Balance Shaft Drive Chain Tensioner shoe.
Important:
DO NOT remove the balance shaft drive chain or Balance Shaft Drive Sprocket.
4.
Remove only the Oil Pump cover assembly.
5.
Install the new Oil Pump Cover Assembly GM P/N 24577081.
6.
Tighten the four long bolts to 12 N.m (106 lb in.).