Oil choice for warranty

[Lonnie]

I just went through our warranty claims for engine failures last year. Out of 8k vehicles we had six. All had extensive investigation because of the facilities we draw on to do maintenance and repair work. The used oil analysis were problems at best but the factory reps we most concerned about maintenance tasks and intervals as evidensed in our record keeping. The used oil analysis were done as a screening step to look for problems. One vehicle, a new Honda had a head gasket leak that lead to overheating and loss of coolant. The oil in the sample was a 10w30 instead of the required 5w-20. Turns out the operator had the oil changed at a garage that we do not have under contract and they know more than Honda about the evil 5w-20 oil, and supplied the 10w30 oil. Honda stated that the oil had nothing to do with the failure and paid the claim. The Honda rep said he has never seen a case in his experience where the oil was the cause of the problem. He said that in this case, the thicker oil does not mean that the engine lasted a little bet longer because it's thicker than the 20 weight oil, and that the opposite might be true. He said in the end, this engine was doomed. The real gremlin was the operator that kept on driving when there was a problem.