GM Service Manual Online
For 1990-2009 cars only

Loss of Coolant Low Coolant Lamp On

Low Coolant Lamp On

Step

Action

Value(s)

Yes

No

1

Test for a faulty low coolant sensor.

Is the sensor faulty?

--

Go to Step 2

Go to Step 3

2

Replace the sensor. Refer to Radiator Surge Tank Replacement .

Does the low coolant lamp continue to stay on?

--

Go to Step 3

System OK

3

Test for a faulty circuit.

Is the circuit faulty?

--

Go to Step 4

--

4

Repair the circuit. Refer to Testing for Continuity in Wiring Systems.

Does the lamp stay on?

--

--

System OK

Loss of Coolant Loss of Coolant

Loss of Coolant

Step

Action

Value(s)

Yes

No

1

  1. Inspect for an external coolant leak.
  2. Do a pressure or dye test on the cooling system. Refer to Cooling System Leak Testing Cooling System Leak Testing.

Is the cooling system to the proper pressure?

--

Go to Step 2

Go to Step 3

2

Test for an internal coolant leak. Do a cylinder leak test. Refer to Oil Leak Diagnosis Oil Leak Diagnosis in Engine Mechanical.

Do you notice an internal loss of coolant?

--

Go to Step 3

--

3

Repair the cooling system components as necessary.

Do you notice a continued loss of coolant?

--

--

System OK