Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Engine Runs Hot &/Or Oil Mixed W/Coolant (96-T-65B)
Reference number: 96-T-65B
ENGINE RUNS HOT &/OR OIL MIXED W/COOLANT
TECHNICAL SERVICE BULLETIN
Superceded Bulletin(s): 96-T-65A
ENGINE RUNS HOT AND/OR ENGINE OIL MIXED WITH ENGINE COOLANT IN ENGINE COOLANT RECOVERY RESERVOIR (REPLACE CYLINDER HEAD ASSEMBLY)
Model(s): 1991-1997 Saturn Vehicles
Group/Seq. No.: 99-06-01-009
Corporation No.: Engine-15
Bulletin No.: 96-T-65B
Date: May, 1999
VEHICLES AFFECTED
1991-1997 Saturn vehicles equipped with SOHC (LK0- 1991 - 1994, L24- 1995 - 1997) engines.
CONDITION
Engine may run hot and/or have engine oil mixed with engine coolant. This condition may be noticeable when checking coolant recovery reservoir level.
CAUSE
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.
CORRECTION
Refer to the following procedure to locate the area where the engine oil is leaking into engine coolant passages.
PROCEDURES
- Remove camshaft from cylinder head.
- Pressure test cooling system.
- 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. (See Fig 1
for examples of areas where cracks may appear.)NOTE: Air pressure may drop slowly, depending on the severity of the crack(s).
- 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.
- Remove cylinder head and gasket.
- Proceed to step 6 and flush engine block and cooling system before installing new cylinder head and new cylinder head gasket.NOTE: Engine block, radiator and heater core must be flushed before installing new cylinder head and new cylinder head gasket.
- 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.NOTE: 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 block for cracks in the oil and engine coolant passages in the cylinder liner area. If cracks are detected, replace engine block.
- If cylinder head gasket is damaged, remove and discard cylinder head gasket, and proceed to step 6.
- Leave upper radiator hose connected to the radiator.
- Remove and discard lower radiator hose.
- Open radiator drain plug. See Fig 2 .
- Insert a hose in the upper radiator hose and flush radiator with clean water until clean water flows from the lower radiator hose connection.
- Remove and discard upper radiator hose.
- Remove water inlet housing and thermostat and discard thermostat. See Fig 3 .
- Remove engine cooling system drain plug, located at the right front of the engine block below the thermostat. See Fig 2 .
- Remove and discard water pump.
- Place shop rags in the exposed cylinder bores.
- Using a hose, fill the exposed water jacket surrounding the cylinders with clean water until clean water comes out of the thermostat location.
- 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.NOTE: Do not install thermostat at this time.
- Install water inlet housing to engine.
- Install engine cooling system drain plug.
- Install new water pump.
- Leave inlet heater hose connected to heater core.
- Remove and discard outlet heater hose.
- Insert hose into inlet heater hose and flush with clean water until clean water comes out of heater core outlet.
- Remove and discard inlet heater core hose.
- Remove and discard coolant recovery hose.
- Remove coolant recovery reservoir and flush thoroughly with clean water.
- Install remanufactured or previously removed cylinder head and new cylinder head gasket.
- Install new radiator, heater and coolant recovery hoses.
- Change engine oil and engine oil filter.
- Prepare a mixture of Calgon(R) or equivalent (automatic dishwasher 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.
- Fill the cooling system with the mixture.
- Run the engine for five minutes.
- Drain the cooling system.
- Repeat Steps 29 through 32 until all oil residue is remove from system.
- Fill the cooling system with clean water.
- Let the engine run five minutes.
- Drain the cooling system completely. See Fig 4 .
- Install new engine thermostat.
- Install cylinder block drain plug. Torque: 35 N-m (26 ft-lbs)
- Close radiator drain plug.NOTE: The vehicle must be level when filling with coolant.
- Fill the system with coolant.
- 1991 - 1996 early vehicles 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).
- Start engine and check for leaks.
- Fill the coolant recovery reservoir to the full cold line after the engine has run for two to three minutes. Install and tighten cap.
PARTS INFORMATION
21015109 Head Asm-Cyl (Remanufactured) (1991-1994)
21015110 Head Asm-Cyl (Remanufactured) (1995)
21015111 Head Asm-Cyl (Remanufactured) (1996-1997)
21000867 Plug-Cyl Hd Oil Gal (1 required, 2 in package)
21006560 Plug-Cm/Shf Brg Hole
21008324 Gasket Kit-Cyl Hd (1991-1994)
21007332 Gasket Kit-Cyl Hd (1995-1997)
21007656 Pump Asm-Water (1991-1994)
21007655 Pump Asm-Water (1995-1997)
21006335 Thermostat Kit-Eng Cool
21030305 Hose Kit-Cool Rcvy Rsvr (1991)
21031098 Hose Kit-Cool Rcvy Rsvr (1992-1997)
21031143 Hose-Htr Rtn Pipe (1991-1997)
21031148 Hose-Cool Rcvy Rsvr Vent (1991-1997)
21031144 Hose-Htr Inl (1991 - 1994)
21031156 Hose-Htr Inl (1995-1997)
21031248 Hose Rad Otlt (1991-1997)
21031146 Hose-Rad Inl (1991-1997)
21030217 Pipe Asm-Htr Otlt (1991)
21031141 Pipe Asm-Htr Otlt (1992-1997)
21030365 Coolant-Eng (1991-1996 Interim, 1 Gallon)
21031164 Coolant-Eng Extended Life (1996 Interim-1997, 1 Gallon)
21000953 Block Asm-Eng (1991-1997)
WARRANTY INFORMATION
To receive credit for this repair during the warranty coverage period, submit a claim through the Saturn Dealer System as follows:
Case Type: VW
Labor Operation No.: Replace Cylinder Head Assembly Remanufactured Cylinder Head
Labor Op. Code: T9715
Time: 9.2 hrs
Add: with A/C 0.5 hrs
Add: with power steering 0.3 hrs
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.