[FRS Dad]

Originally Posted by poptart

ATF is likely preferable to thick gear oil, but yeah we still don't know what it was. But I still would not feel good about it, even if the viscosity is similar. ATF has a different application than an engine. It would never be exposed to combustion by-products and gas dilution inside the transmission. I read on bitog forum, ATF typically has seal swelling agents, friction modifiers, and
different additive package than engine oil.

I doubt the engine will grenade tomorrow but their negligence is inexcusable. That dealer owes him compensation. Oil chemistry is a science. They recommend a certain type of oil for a reason. To answer someone's earlier question, I have no doubt if an owner brought a car for service and told the dealer you had accidentally been driving it with pure transmission fluid because some shadetree mechanic messed up the oil change, they'd use that as an excuse to deny warranty coverage if you ever had problems. I've read threads where apparently properly maintained cars have spun main bearings.

Agreed on all points. So the question is, what is reasonable compensation for exposing the customer's engine to operating for twenty miles with the incorrect lubricant.

Sadly, had the shop missed the error and the owner ran the car until it spun a main bearing, he'd be getting a new engine. It's the gray area that's a problem for him.