Engine Runs Hot and/or Engine Oil Mixed with Engine Coolant In Engine Coolant Recovery Reservoir

Engine may run hot and/or have engine oil mixed with engine coolant. This condition may be noticeable when checking coolant recovery reservoir level.

Some 1991-1997 SOHC engines may develop a crack on or near the camshaft journals and surrounding casting areas allowing engine oil to mix with engine coolant.

Refer to the following procedure to locate the area where the engine oil is leaking into engine coolant passages.

Important: When required, refer to the appropriate year service manuals when performing the following procedures.

1. Remove camshaft from cylinder head.
2. Pressure test cooling system.





3. While monitoring the pressure gauge for air pressure drop, inspect all hose connections and visible joints for engine coolant leaks. Inspect the camshaft journals and surrounding areas using a bright light, to help locate hairline cracks. (Refer to illustrations for examples of area where cracks may appear.)

Important: Air pressure may drop slowly, depending on the severity of the crack(s).

4. If a crack is detected in one or more of the areas shown, cylinder head assembly must be replaced. If no crack is detected, proceed to step 5.

4.1.	Remove cylinder head and gasket.

4.2.	Proceed to step 6 and flush engine block and cooling system before installing new cylinder head and new cylinder head gasket.

Important: Engine block, radiator and heater core must be flushed before installing new cylinder head and new cylinder head gasket.

5. If pressure bleeds down, but no leaks or cracks are detected, remove cylinder head assembly and inspect the cylinder head gasket for damage between the oil and engine coolant passages.

•	If cylinder head gasket is damaged, remove and discard cylinder head gasket, and proceed to step 6.

Important: Engine block, radiator and heater core must be flushed before installing cylinder head and new cylinder head gasket.

•	If cylinder head gasket is not damaged, inspect engine blocks for cracks in the oil and engine coolant passages in the cylinder liner area. If cracks are detected, replace engine block.

6. Leave upper radiator hose connected to the radiator.
7. Remove and discard lower radiator hose.
8. Open radiator drain plug.
9. Insert a hose in the upper radiator hose and flush radiator with clean water until clean water flows from the lower radiator hose connection.
10. Remove and discard upper radiator hose.
11. Remove water inlet housing and thermostat and discard thermostat.
12. Remove engine cooling system drain plug, located at the right front of the engine block below the thermostat.
13. Remove and discard water pump.
14. Place shop rags in the exposed cylinder bores.
15. Using a hose, fill the exposed water jacket surrounding the cylinders with clean water until clean water comes out of the thermostat location.
16. Remove shop rags from cylinder head bores and apply a liberal amount of 5W - 30 engine oil to the cylinder liners to help prevent corrosion.

Important: Do not install thermostat at this time.

17. Install water inlet housing to engine.
18. Install engine cooling system drain plug.
19. Install new water pump.
20. Leave inlet heater hose connected to heater core.
21. Remove and discard outlet heater hose.
22. Insert hose into inlet heater hose and flush with clean water until clean water comes out of heater core outlet.
23. Remove and discard inlet heater core hose.
24. Remove and discard coolant recovery hose.
25. Remove coolant recovery reservoir and flush thoroughly with clean water.
26. Install remanufactured or previously removed cylinder head and new cylinder head gasket.
27. Install new radiator, heater and coolant recovery hoses.
28. Change engine oil engine oil filter.



29. Prepare a mixture of Calgon ® or equivalent (automatic dishwater detergent), and water at the rate of 59 milliliters (two ounces) (dry measure) to 3.8 Liters (1 gallon) of water. The cooling system holds approximately 7.6 liters (two gallons) of coolant.



30. Fill the cooling system with the mixture.
31. Run the engine for five minutes.



32. Drain the cooling system.
33. Repeat Step 29 through 32 until all oil residue is remove from system.
34. Fill the cooling system with clean water.
35. Let the engine run five minutes.
36. Drain the cooling system completely.
37. Install new engine thermostat.
38. Install cylinder block drain plug.
39. Close radiator drain plug.

Important: The vehicle must be level when filling with coolant.

40. Fill the system with coolant.

•	1991-1996 early vehicle equipped with "Green" Saturn non-phosphate ethylene glycol-base coolant, fill the cooling system with a 50/50 mixture of new Saturn non-phosphate ethylene glycol-base coolant (P/N 21030365, 3.8 Liter [one gallon] container).

•	1996 interim and 1997 vehicles equipped with "Orange" Saturn DEX-COOL ™ extended-life engine coolant, fill the cooling system with a 50/50 mixture of new Saturn DEX-COOL ™ extended-life engine coolant (P/N 21031164, 3.8 Liter [one gallon] container).

41. Start engine and check for leaks.
42. Fill the coolant recovery reservoir to the full cold line after the engine has run for two or three minutes. Install and tighten cap.

To receive credit for this repair during the warranty coverage period, submit a claim through the Saturn Dealer System as follows: