If you bought it used, might be worth a CarFax on it's title and see if you can trace it back to a flood state it was moved out of. However the damage you describe sounds like "crankcase explosion" may have caused it. That's when Pollution Control Valve or System isn't getting all the fumes/vapors from the crankcase and a bit of fire passing a piston causes an explosion in the crankcase.
I'd trade it in for a different GM product, since they probably will not even check it, just give you book credit on it, and I suspect they may be to blame for it's condition anyway.
Hi,
I have a 2007 Pontiac G6 Convertible 3.9L engine, 47K miles. I have been doing regular oil changes at the dealership.
It started leaking oil recently.
After the diagnostic, dealership found oil leaking from
-Front crank seal
-Lower intake gaskets
-Upper intake gaskets
-Coolant crossover pipe
-Sealant
-Thermostat with gasket
Repair quote: $1950
I took it to a local mechanic thinking it might be cheaper, but he diagnosed it as
the problem with your car is:
rear main seal leaking
oil pan leaking
rear head gasket leaking
i have to remove the engine outside the car
remove both cylinders head and send them to machine shop to re service flat head , we will put new bolts and new head gasket
parts and labor 2000-2200
I am down $170 dealer diagnostic and $140 mechanic diagnostic and getting very different diagnosis.
KBB says the car is worth 5-6K for private party sale and 4K for trade-in.
Any advice? Should I go to a third mechanic? Is it worth spending so much on repairs when the car's value isn't much?
Is it better off selling this one? I'm OK buying a new one but would like to get the most value out of my dollar.

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