[FRS Dad]

Okay, I just got off the phone with my kid brother Matt. He's a general mechanic at a dealership but he's familiar with the engine and owns a couple of Subies as winter cars himself.

1) He agrees with the OP that it's impossible to know if depriving the engine of proper lubricant for any period of time started some damage process that could take many years or miles to fully materialize.

2) He would suspect any trouble if it did arise would be in the bearings (crankshaft, camshaft) and not in the cylinder walls or piston.

3) He agrees with the shop that at this point there's nothing to indicate damage provided the engine is running normally and it's not smoking, and a tear down would be way more trouble than it's worth for both parties.

4) His gut instinct is that the car will be fine.

He said, were it his car, he would do the following:

Get a letter from the dealer on letterhead acknowledging the shop's error, date and mileage.

Get the extended warranty in writing with specific language regarding coverage for repair of any problems related to oil, oil starvation and premature engine wear.

Trade the car before the extended warranty lapses.

So now I have to reverse myself because I think in this instance you do want an attorney to handle the wording of the demand to the dealer both for the letter and to write the wording of the warranty. This should run a few hundred dollars and I don't think the dealer is on the hook for it.

Alternately you could start the process with a certified letter (return receipt requested) to the GM along the lines of:

"Dear (GM)

As you're aware, during a recent service at your facility, your technician inadvertently drained my vehicle's engine crankcase of motor oil and replaced it with transmission fluid. I appreciate how quickly the error was discovered and your shop's proactive measures to remedy the error, however the car was released to me and driven for several miles before the mistake was identified.

My concern clearly is that operating the engine with insufficient lubricant could have caused damage to any number of sensitive internal engine components, and that the damage process may not be readily evident at this early stage.

My understanding is that you have offered to become a warrantor of the engine for a period of 100,000 miles to alleviate my concerns. I am prepared to accept your offer and conclude the matter under the following conditions:

-Please provide me in writing a statement on letterhead acknowledging the specific shop error and include the vehicle's VIN, the date and time of the service and the car's mileage.

-Please provide me a copy of the proposed language of the extended warranty.

Lastly, as an act of goodwill, I would appreciate it if the shop would agree to perform future regularly scheduled oil changes at no charge. Thank you for your time, and I look forward to hearing from you.

Best
(OP)"

Now if I'm the dealer here I'm concerned about a letter floating around out there where I admit liability in exchange for no assurance that the owner isn't going to then take my letter, take my warranty and then go ahead and sue me for something anyway, so don't be surprised if he wants some form of a release that limits his exposure to the warranty. A lawyer should be consulted for approval of the wording of any release.

On your side, the warranty needs to have specific language outlining the process for how damage is evaluated and repaired.