GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

  1. Make a visual inspection of the cooling system.
  2. Inspect the ground under the vehicle.

Is there coolant visible on the ground?

--

--

Go to Step 2

2

Inspect the radiator for stains and wetness.

Are there any stains or is there any wetness on the radiator?

--

Go to Step 3

Go to Step 4

3

Repair as necessary.

Is there still a coolant loss?

--

Go to Step 4

--

4

Inspect the coolant hoses for stains and wetness.

Are there any stains or is there any wetness on the coolant hoses?

--

Go to Step 5

Go to Step 6

5

Repair as necessary.

Is there still a loss of coolant?

--

Go to Step 6

--

6

Inspect the water pump for stains and wetness.

Are there any stains or is there any wetness on the water pump?

--

Go to Step 7

Go to Step 8

7

Repair as necessary.

Is there still a loss of coolant?

--

Go to Step 10

--

8

Inspect the heater core for stains or wetness .

Are there any stains or wetness on the heater core?

--

Go to Step 9

Go to Step 10

9

Repair as neccessary.

Is there still a loss of coolant?

--

Go to Step 10

System OK

10

Inspect the coolant recovery reservoir or surge tank for leakage.

Does the coolant overflow from the reservoir with the engine off?

--

Go to Step 11

--

11

Inspect the radiator cap for proper pressure retention.

Does the radiator cap maintain the correct pressure?

103 kPa (15 psi)

Go to Step 12

Go to Step 13

12

Inspect the temperature reading of the thermostat. Refer to Thermostat Diagnosis .

Is the temperature too high?

--

Go to Engine Overheating

Go to Step 14

13

Replace the radiator cap.

Is there still a coolant loss?

--

Go to Step 14

System OK

14

Inspect the coolant concentration.

Is the coolant concentration too low?

--

Go to Step 15

System OK

15

Replace the coolant with the proper mixture of DEX-COOLâ„¢. Refer to

Notice: When adding coolant, use DEX-COOL® coolant. If silicated coolant is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolant will require change sooner-at 50 000 km (30,000 mi) or 24 months.

in Cautions and Notices.

Is there still a coolant loss?

--

--

System OK