Crankcase Contamination Due To Coolant In The Engine Oil - Reseal Casting Plug - keywords 1.6L contaminated galley gallery in into L91 loss no sludge

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

On rare occasions, a loss of coolant may be experienced with no external coolant leaks. This may be the result of coolant in the crankcase but it may not be obvious by simply removing the oil fill cap or dipstick for inspection.

If the SI diagnostics do not isolate the cause of this concern, follow SI procedures to remove the valve rocker cover and inspect the area around the casting plugs that are between the spark plug holes for signs of coolant or sludge build up as shown below. If necessary, pressure test the cooling system while inspecting the casting plugs for signs of coolant. If coolant or sludge is present, reseal the casting plugs for evaluation by following the procedure below:

1. Remove the casting plugs and thoroughly clean the threads.
2. Apply Pipe Sealant w/Teflon® to the threads of the plug. GM part number 12346004 or Canadian part number 10953480 is suggested.
3. Install the casting plugs and torque them to 95 N·m (70 lb ft).
4. Install the valve rocker cover by following SI procedures.
5. Change the engine oil and filter.

Here are a couple of examples that show a casting plug that was leaking coolant into the crankcase:

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.