My friend just went through this with his daughter's Equinox. Her's snuck in under the extended warranty by 127 miles. The dealer replaced the pistons and the piston rings.
From my time at a very nice family-owned Chrysler dealership, I can offer a couple of suggestions. GM has more customer-unfriendly business practices than most other manufacturers, but there are some policies they all have in common. One of the things the Chrysler dealers don't advertise is they have an account they can use to pay for things that are technically out-of-warranty, but really shouldn't have happened. In our case there still was a mileage limit, and those funds were limited to $100,000.00 per year. They had to limit that to good or repeat customers, but it was at the discretion of the dealer. Chrysler would accept those warranty claims as one of their "customer-friendly" business practices. Be aware the dealer has to be careful to not use this fund up before the end of the year, so he is going to use it for cooperative or appreciative customers. When someone comes through the door yelling and angry, no one is going to be in a mood to help.
Chances are your vehicle is too far beyond the mileage warranty, which has already been extended, but a cooperative dealer might be able to offer some help, especially if you bought the vehicle from them.
The next option is to ask for a meeting with the district representative. Ours visited each dealership about once per month to address issues the dealer was unable to due to franchise restrictions. Most his day was spent drinking coffee and visiting with the sales people, but we all knew if the dealership owner's office door was closed, they were to be left alone. In those meetings, the dealer is the customer's advocate and will help make the case and keep the facts straight. This district rep. Even offered to warranty the battery in my Dynasty even though it was seven years old. He said, "he has the authority to warranty anything". Don't waste a lot of his time telling him how this has inconvenienced you. Just state your case why this is not what you expect out of their product.
The things to keep in mind is this is a common failure GM knows all about, but historically, they emphasize short-term profits right now vs. Long-term customer satisfaction and repeat business. This is one of the major differences in the corporate culture between GM and Chrysler. Chrysler wants to keep customers happy so they'll come back for their next car, but that really cuts into their profits. GM is less likely to worry about your word-of-mouth advertising. They have a lot of other tricks figured out to sell new cars. You need to include in your argument the number of people who are going to be aware of the outcome and how it was handled. One of the famous sayings in our dealership was "it takes more advertising dollars to get one new customer than it takes to keep ten current customers happy". The dealer knows they have to keep you happy to get you back, and if they don't, they could lose ten prospective buyers. Their district rep. Is only concerned with saving GM money. He doesn't get paid according to how many cars they sell.
Also be aware of the differences in dealerships. In my city we have the Chrysler dealer, the GMC dealer down the road, the Cadillac dealer across town, and the Toyota dealer that are all very reputable. They will borrow service manuals and special tools back and forth, and often repair each others' trade-ins. The one notable exception is the Chevy dealer. He has more ways figured out to separate you from your money after the sale than even GM came up with. His reputation is so bad, they laid off the majority of their service department for lack of work, and people drive 30 miles to a different town if they have to have a Chevy.
We used to have a really good Ford, Saturn, and especially an import dealer too, but the owner of the Chevy dealership bought them all up, and now they too have equally bad reputations. If your dealer is of this mentality, consider looking for help from a Chevy dealer in a nearby town.
As a last resort, consider trading your vehicle in at the dealer who won't give you any help. Now he is going to be forced to admit your trade-in has very low value because of their engine design. This could end up being a sale for one of his competitors. GM dealers are also well-known to have "secret warranties" they don't want you to know about. If they can get the manufacturer to pay for the repairs to your vehicle after you trade it in, they will be able to offer you closer to what it really should be worth. They'll tell you they're doing that to help you out, but they always know ahead of time what they're going to have to put into a vehicle before they can sell it. This might be a way to get the value out of it without forcing them to admit anything.
Also be aware when you're standing at the service desk trying to get this handled, there's a real good chance there will be a new-car salesman standing nearby, "killing time". One of their favorite tricks to finding new customers is to overhear about your car's problem, then suggest it would be a better value to put the repair money toward a new car instead. There's nothing illegal or unethical about that practice, but it is one of their many high-pressure tactics they use to make sales. This time that might work in your favor.
Tuesday, January 28th, 2020 AT 5:47 PM