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Subject: Models: Low Engine Coolant Level Indicator Always On (Diagnose Low Coolant Level System Operation/Check Sensor for Oil Contamination) 2000-2002 Buick Century, Regal 2000-2001 Chevrolet Lumina 2000-2002 Chevrolet Impala, Monte Carlo 2000-2002 Pontiac Grand Prix 2000-2002 Oldsmobile Intrigue Condition Some customers may comment that the low engine coolant level indicator is always illuminated. Cause The cause of this condition may be due to engine oil contaminating the coolant. Possible sources of oil contamination are internal engine leaks, improper service procedures, or the addition of some types of anti-leak additives to the cooling system. Once in the coolant, the oil leaves deposits on the level sensor creating an insulating film. This film results in a false activation of the coolant level indicator. Correction Diagnose low coolant level system operation and check the sensor for oil contamination using the procedure listed below. Important: No coolant supplements should be used in GM cooling systems, other than what is approved and recommended by GM. The use of “aftermarket” over-the-counter sealing and cooling supplements may affect the operation of the low coolant level sensor. Discoloration of the coolant recovery bottle is normal and does not necessarily indicate that coolant contamination is present. Flush cooling system only when instructed by this bulletin. 1. Verify that the coolant is at proper level in the radiator and the coolant recovery bottle. If the coolant is low, add proper amount of 50/50 water and DEX-COOL® mixture. If the low coolant light operates properly, diagnose the cooling system for loss of coolant as outlined in SI. DO NOT proceed further with this bulletin. 2. Remove the low coolant level sensor. Refer to Coolant Level Module Replacement in the Engine Cooling sub-section. 3. With the key on, the engine off and the coolant level sensor disconnected from the vehicle wiring harness, observe the low coolant light: • Light is on — Chassis wiring or instrument cluster concern. Follow the appropriate diagnostic information in SI. • Light is out — Proceed to Step 4.

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Draining 1. Bring the engine to normal operating temperature and turn the engine off. With the cooling system under pressure, inspect cooling system hoses and clamped hose connections for leaks, excessive deterioration or contact wear. Inspect radiator installation retention. Note any discrepancies and proceed. 2. WARNING: Never remove the pressure relief cap while the engine is operating or when the cooling system is hot. Failure to follow these instructions can result in damage to the cooling system or engine or personal injury. To avoid having scalding hot coolant or steam blow out of the degas bottle when removing the pressure relief cap, wait until the engine has cooled, then wrap a thick cloth around the pressure relief cap and turn it slowly. Step back while the pressure is released from the cooling system. When you are sure all the pressure has been released, (still with a cloth) turn and remove the pressure relief cap. CAUTION: The coolant must be recovered in a suitable, clean container for reuse. If the coolant is contaminated, it must be recycled or disposed of correctly and replaced. CAUTION: Some vehicle cooling systems are filled with Motorcraft Premium Engine Coolant VC-4-A (in Oregon VC-5, in Canada CXC-10) or equivalent meeting Ford specification ESE-M97B44-A (green color). Others are filled with Motorcraft Premium Gold Engine Coolant VC-7-A meeting Ford specification WSS-M97B51-A1 (yellow color). Always fill the cooling system with the same coolant that is present in the system. Do not mix coolant types. NOTE: Less than 80 percent of coolant capacity can be removed from the engine. Dirty, rusty or contaminated coolant requires replacement. Drain engine coolant as follows: Open radiator draincock to drain the coolant system. Disconnect radiator overflow hose from radiator filler neck connection. Remove radiator coolant recovery reservoir and empty the fluid. Flush radiator coolant recovery reservoir with clean water. Drain and reinstall radiator coolant recovery reservoir and radiator overflow hose and clamp to radiator filler neck. Correct, repair or install new components found to be inoperative in Step 1. Filling and Bleeding with RADKITPLUS 1. Using the special tool, install the RADKITPLUS and follow the RADKITPLUS manufacturer’s instructions to fill and bleed the cooling system. Filling and Bleeding without RADKITPLUS CAUTION: Engine coolant provides freeze protection, boil protection, cooling efficiency and corrosion protection to the engine and cooling components. In order to obtain these protections, the engine coolant must be maintained at the correct concentration and fluid level in the degas bottle. When adding engine coolant, use a 50/50 mixture of engine coolant and clean, drinkable water. To maintain the integrity of the coolant and the cooling system:

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Draining WARNING: Never remove the pressure relief cap while the engine is operating or when the cooling system is hot. Failure to follow these instructions can result in damage to the cooling system or engine or personal injury. To avoid having scalding hot coolant or steam blow out of the degas bottle when removing the pressure relief cap, wait until the engine has cooled, then wrap a thick cloth around the pressure relief cap and turn it slowly. Step back while the pressure is released from the cooling system. When you are sure all the pressure has been released, (still with a cloth) turn and remove the pressure relief cap. CAUTION: The coolant must be recovered in a suitable, clean container for reuse. If the coolant is contaminated it must be recycled or disposed of correctly. CAUTION: Care must be taken to ensure the accessory drive belt does not become contaminated with engine coolant. CAUTION: Some vehicle cooling systems are filled with Motorcraft Premium Engine Coolant VC-4-A (in Oregon VC-5, in Canada CXC-10) or equivalent meeting Ford specifications ESE-M97B44-A (green color). Others are filled with Motorcraft Premium Gold Engine Coolant VC-7-A or equivalent meeting Ford specification WSS-M97B51-A1 (yellow color). Always refill the cooling system with the same coolant that was drained from the system. Do not mix coolant types. 1. Release the pressure in the cooling system by slowly turning the pressure relief cap one half turn counterclockwise. When the pressure is released, remove the pressure relief cap. 2. NOTE: Less than 80% of coolant can be recovered with the engine in the vehicle. Dirty, rusty or contaminated coolant requires replacement. Place a suitable container below the radiator draincock. If equipped, disconnect the coolant return hose at the oil cooler. Close the radiator draincock when finished. Filling and Bleeding With RADKITPLUS 1. Using the special tool, install the RADKITPLUS and follow the RADKITPLUS manufacturer’s instructions to fill and bleed the cooling system. Filling and Bleeding Without RADKITPLUS CAUTION: Engine coolant provides freeze protection, boil protection, cooling efficiency and corrosion protection to the engine and cooling components. In order to obtain these protections, the engine coolant must be maintained at the correct concentration and fluid level in the degas bottle. When adding engine coolant, use a 50/50 mixture of engine coolant and clean, drinkable water. To maintain the integrity of the coolant and the cooling system:

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SUBJECT: Engine Coolant Temperature Sensor Related Diagnostic Trouble Code(s) and/or the Following Conditions: Hard Start, Erratic Idle, Rough Running. Engine Overheating, Low and/or Leaking Coolant, and/or Service Engine Soon Lamp Illuminated. (Replace Engine Coolant Temperature Sensor with New Design Sensor- P/N 21025106) MODELS AFFECTED: 1991-2001 Saturn S-Series vehicles CONDITION: Customers may comment about various driveability and/or engine operating concerns including: hard start, erratic idle, rough running, engine overheating, low and/or leaking coolant, and/or Service Engine Soon lamp illuminated. CAUSE: This condition may be caused by a cracked engine coolant temperature sensor. CORRECTION: Replace engine coolant temperature sensor, inspect and if necessary replace sensor harness connector. Refer to procedure in this bulletin to replace engine coolant temperature sensor and Parts Requirements for specific parts information. PROCEDURE 1. Disconnect engine coolant temperature sensor electrical connector and inspect sensor and connector terminals for corrosion and/or evidence of engine coolant. ^ If terminals are corroded or if there is evidence of engine coolant proceed to step 4. ^ If terminals are not corroded and there is no evidence of engine coolant, reconnect the electrical connector and continue to next step.

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Condition Some customers may comment on excessive engine coolant consumption, or an engine coolant leak near or under the throttle body area of the upper intake manifold. Cause Upper intake manifold composite material may degrade around the EGR stove pipe and could result in an internal or external coolant leak. Correction 1. Follow the upper intake manifold removal instructions found in the Engine Unit Repair Section of the Service Information Manual. 2. Refer to the arrow in the illustration of the upper intake manifold above. Inspect the inner diameter of the EGR passage for signs of material degradation. Degradation will appear as “pitting” of the composite material in the EGR port passage. 3. If degradation of upper intake manifold composite material is found, replace the lower and upper intake manifolds with the following part numbers: • Gasket Kit, Upper Intake Manifold — 89017554 • Manifold Kit, Upper Intake — 89017272 • Gasket, Lower Intake Manifold — 89017400 • Manifold, Lower Intake — 24508923 4. Follow the lower and upper intake manifold installation instructions found in the Engine Unit Repair Section of the appropriate Service Manual. 5. If degradation is not apparent, skip to Step 7. 6. Verify the repair. 7. If no degradation is found, evaluate the vehicle for other causes of excessive coolant consumption as noted in the Engine Diagnosis Section of the appropriate Service Manual.