My family and I recently took a trip in our 2000 Ford Taurus - it had around 163,000 miles but has been regularly serviced and had a valve job and header replaced. Before leaving town, we had the car serviced, including an oil change. We drove it over 2500 miles - highway and in town at our destination. It started making a clicking noise and the check engine light started flashing. It didn’t sound or feel right. We drove it approximately 20 - 30 miles at a reduced speed to the next town. While driving slowly in town to a stop, the red oil light flickered and stayed on for periods. We checked the oil and it wasn’t registering on the stick. Added 4 quarts and it finally registered in the cross-hatches of the stick (about half-way). Drove to a motel and took it to the local dealer the next day. Service manager listened to the engine. He said the sound was coming from low in the engine, and it was ruined (although drivable). He said it would be too risky to continue our trip under this condition, risking a full breakdown on the road.
There was no evidence of an oil leak anywhere - engine, tail pipe, on the ground. He suspects the mechanic we used in our home town forgot to put oil back in during the oil change - he thinks this is the probable cause.
We left the car at the dealer in another state and returned home. When I spoke to our hometown mechanic, he said it couldn’t have been his shop forgetting to put in oil, because it would have developed problems soon after getting on the highway and driving highway miles (high RPM and operating temperature). He said the likely explanation is faulty oil control rings - this would explain a steady consumption of oil over the miles driven without evidence of leaking or smoking. He said the piston rings could be fine, so we wouldn’t notice smoke out the tail pipe.
I would like opinions about the two scenarios and what the likely explanation is.