Rough Running Conditions and Smoke From Exhaust on Scion tC

The head gasket may fail due to a defect in manufacturing of the cylinder block.

On this vehicle, the head bolts are known to pull the threads out of the engine block, allowing the head to slightly lift, and causing head gasket failure. Symptoms may include:

• Overheating
• White smoke from exhaust
• Rough running conditions and/or inability to start or idle
• White or cream colored oil on dipstick
• Check engine light
• OBD Trouble Codes P2181, P0300

When the head gasket fails, the bolt holes for the head bolts must be repaired before the cylinder head can be remounted.

This issue is not always preventable, but to help avoid it, never run the engine if the engine temperature is ever above the normal range.