Lumina V6-3.1L VIN J (2000)
Coolant Level Sensor: All Technical Service Bulletins
Instruments - Low Coolant Indicator Always ON
Bulletin No.: 04-06-02-007
Date: August 11, 2004
TECHNICAL
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.
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(R) 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.