GM Service Manual Online
For 1990-2009 cars only

Loss of Coolant 3.5L V6 LX5

Step

Action

Value(s)

Yes

No

1

Check for a leaking radiator. Refer to Cooling System Leak Testing .

Is the radiator leaking?

--

Go to Step 2

Go to Step 3

2

Repair or install new parts as necessary.

Is the repair complete?

--

System OK

--

3

Check for a leaking heater core. Refer to Cooling System Leak Testing .

Is the heater core leaking?

--

Go to Step 4

Go to Step 5

4

Check for a faulty surge pressure cap.

Is the cap operating properly?

--

Go to Step 5

Go to Step 2

5

Check for a leaking surge tank hose(s), a cracked surge tank or a nicked surge tank neck. Refer to Radiator Surge Tank Replacement .

Is the reservoir or the hose leaking?

--

Go to Step 2

Go to Step 6

6

Check for any loose or damaged hoses and connections.

Are any hoses damaged or are any hose connections leaking?

--

Go to Step 2

Go to Step 7

7

Check for a cracked thermostat housing or a leaking thermostat seal. Refer to Engine Coolant Thermostat Replacement .

Is the thermostat housing cracked or is there a seal leak?

--

Go to Step 2

Go to Step 8

8

Check for a cracked water pump or a leaking water pump gasket.

Is the water pump cracked or is there a leaking gasket?

--

Go to Step 2

Go to Step 9

9

Check for a cracked water pump shaft seal.

Is the water pump shaft seal leaking?

--

Go to Step 10

Go to Step 11

10

Replace the water pump. Refer to Water Pump Replacement .

--

System OK

Go to Step 11

11

Check for a leaking engine block coolant drain hole plug or knock sensor.

Are any drain hole plugs or knock sensors leaking?

--

Go to Step 2

Go to Step 12

12

Check for any leaking cylinder head core plugs.

Are the cylinder head core plugs leaking?

--

Go to Step 2

Go to Step 13

13

Check for a leaking cylinder head gasket(s), vent(s) or a cracked cylinder head(s).

Is the cylinder head gasket leaking or is the cylinder head cracked?

--

Go to Step 2

Go to Step 14

14

Check for a cracked throttle body or a gasket leak.

Is the throttle body cracked or is there a gasket leak?

--

Go to Step 2

Go to Step 15

15

Check for a cracked cylinder block. Refer to Engine Replacement .

Is the cylinder block cracked?

--

Go to Step 2

Go to Step 16

16

Check for any porous castings.

Are the castings OK?

--

System OK

--

Loss of Coolant 3800 V6 L36

Step

Action

Value

Yes

No

1

Check for an incorrect or faulty radiator filler cap. Refer to Pressure Cap Testing .

Was an incorrect cap installed, or is the cap faulty?

--

Go to Step 2

Go to Step 3

2

Replace the filler cap.

Is there still a coolant loss?

103 kPa (15 psi)

Go to Step 3

System OK

3

Check for a leaking coolant recovery reservoir or reservoir hose.

Is the coolant recovery reservoir leaking, or is the reservoir hose leaking?

--

Go to Step 4

Go to Step 5

4

Replace the reservoir or the hose. Refer to Coolant Recovery Reservoir Replacement .

Is there still a loss of coolant?

--

Go to Step 5

System OK

5

Check for any loose or damaged radiator hoses and connections.

Are any radiator hoses loose or damaged?

--

Go to Step 6

Go to Step 7

6

Re-seat the hoses and clamps. If necessary, replace the hoses and the clamps. Refer to Radiator Inlet Hose Replacement or Radiator Outlet Hose Replacement .

Is there still a coolant loss?

--

Go to Step 7

System OK

7

Check for a water pump gasket leak.

Is there a leak at the water pump gasket?

--

Go to Step 8

Go to Step 9

8

Replace the water pump gasket. Refer to Water Pump Replacement .

Is there still a coolant loss?

--

Go to Step 9

System OK

9

Check for a seal leak at the water pump.

Is there a leak at the water pump seal?

--

Go to Step 10

Go to Step 11

10

Replace the water pump. Refer to Water Pump Replacement .

Is there still a coolant loss?

--

Go to Step 11

System OK

11

Check if the cylinder head bolts are tightened to specification.

Are the cylinder head bolts tightened to the proper specification?

--

Go to Step 13

Go to Step 12

12

Tighten the cylinder head bolts to the proper specification. If necessary, replace the cylinder head gasket.

Is there still a coolant loss?

--

Go to Step 13

System OK

13

Check for any coolant leaks at the radiator. Refer to Cooling System Leak Testing .

Does the radiator have any leaks?

--

Go to Step 14

Go to Step 15

14

  1. Inspect the radiator.
  2. Replace the radiator as necessary.
  3. Refer to Radiator Replacement .

Is there still a coolant loss?

--

Go to Step 15

System OK

15

Check the following for leaks:

  1. The intake manifold
  2. The engine block coolant drain hole plug or the knock sensor
  3. The heater core

Are any leaks occurring at any of these places?

--

Go to Step 16

System OK

16

Make the necessary repairs or replace the components as necessary in order to repair the leak.

Is there still a coolant loss?

--

--

System OK