Low Engine Coolant Level Indicator Always On (Diagnose Low Coolant Level System Operation/Check Sensor for Oil Contamination)

Subject: Low Engine Coolant Level Indicator Always On (Diagnose Low Coolant Level System Operation/Check Sensor for Oil Contamination)

Models: 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.

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. Download File PDF