Loss of Coolant (M 35)

Step	Action	Yes	No
DEFINITION: The cooling system is losing coolant either internally or externally.
1	Were you sent here from Symptoms or another diagnostic?	Go to Step 2	Go to Symptoms - Engine Cooling
2	Repair any present DTCs. Refer to Diagnostic System Check - Engine Cooling . Is the action complete?	Go to Step 3	-
3	Inspect the coolant level. Is the coolant at the proper level?	Go to Step 6	Go to Step 4
4	Fill the cooling system to the proper level. Refer to Draining and Filling Cooling System (LA3, LY9) or Draining and Filling Cooling System (LY7) or Draining and Filling Cooling System (LS6) . Is the action complete?	Go to Step 5	-
5	If the engine is suspected to have a coolant leak into a cylinder, the coolant can hydraulically lock the engine. Does the engine crankshaft rotate?	Go to Step 6	Go to Step 22
6	Engine overheating can cause a loss of coolant. Is the engine overheating?	Go to Step 23	Go to Step 7
7	Extended operation with a low coolant level can cause engine internal component failure. Is the engine knocking?	Go to Step 25	Go to Step 8
8	Idle the engine at normal operating temperature. Inspect for heavy white smoke coming out of the exhaust pipe. Is a heavy white smoke present from the exhaust pipe?	Go to Step 9	Go to Step 10
9	Coolant in the exhaust system creates a distinctive, burning coolant odor in the exhaust. Condensation in the exhaust system can cause an odorless white smoke during engine warm up. Does the white smoke have a burning coolant type odor?	Go to Step 24	Go to Step 10
10	With the engine idling, inspect the surge tank. Does the coolant recovery system discharge coolant while the engine is idling?	Go to Step 15	Go to Step 11
11	Visually inspect the hoses, pipes and hose clamps at the following locations: Coolant bypass Coolant reservoir Heater core Coolant bypass valve Radiator Are any of the hoses, clamps or pipes leaking?	Go to Step 19	Go to Step 12
12	Visually inspect the following components: Coolant pressure cap Core plugs Cylinder head gaskets Engine block Hot water shut off valve Intake manifold Radiator Thermostat housing Water pump Are any of the listed components leaking?	Go to Step 19	Go to Step 13
13	Pressure test the cooling system. Refer to Cooling System Leak Testing . With the cooling system pressurized, visually inspect the components listed in steps 11 and 12. Are any leaks present?	Go to Step 19	Go to Step 14
14	Pressure test the coolant pressure cap. Refer to Pressure Cap Testing . Does the coolant pressure cap hold pressure?	Go to Step 16	Go to Step 20
15	Pressure test the coolant pressure cap. Refer to Pressure Cap Testing . Does the coolant pressure cap hold pressure?	Go to Step 26	Go to Step 20
16	Inspect for the following conditions: A coolant smell inside of the vehicle. Coolant in the HVAC module drain tube. Coolant on the vehicle floor covering near the HVAC module. Is coolant present?	Go to Step 21	Go to Step 17
17	Inspect the underside of the engine oil fill cap for a gray/white milky substance. Is there a milky substance on under the oil fill cap?	Go to Step 18	Go to Step 19
18	Inspect the engine oil fluid level indicator for a gray/white milky substance. Is there a milky substance on the engine oil fluid level indicator?	Go to Step 24	Go to Step 19
19	Repair or replace the leaking component. Refer to the appropriate repair. Is the repair complete?	Go to Step 27	-
20	Replace the coolant pressure cap. Is the repair complete?	Go to Step 27	-
21	Replace the heater core. Refer to Heater Core Replacement in Heating, Ventilation and Air Conditioning. Is the repair complete?	Go to Step 27	-
22	Repair the engine no crank condition. Refer to Engine Will Not Crank - Crankshaft Will Not Rotate in Engine Mechanical - 2.6L and 3.2L. Is the repair complete?	Go to Step 27	-
23	Repair the engine overheating condition. Refer to Engine Overheating (LY7) or Engine Overheating (LA3, LY9) or Engine Overheating (LS6) . Is the repair complete?	Go to Step 27	-
24	Repair the engine internal coolant leak. Refer to Coolant in Combustion Chamber or Coolant in Engine Oil in Engine Mechanical - 2.6L and 3.2L. Is the repair complete?	Go to Step 27	-
25	Repair the engine knock. Refer to Lower Engine Noise, Regardless of Engine Speed in Engine Mechanical - 2.6L and 3.2L. Is the repair complete?	Go to Step 27	-
26	Repair the combustion pressure in the cooling system problem. Refer to Cylinder Leakage Test in Engine Mechanical - 2.6L and 3.2L. Is the repair complete?	Go to Step 27	-
27	Operate the system in order to verify the repair. Did you find and correct the condition?	System OK	Go to Step 2