problem with O2 sensor and manifold

Hi guys,

I have a 2011 aveo LS hatchback and recently I had a leak in one of the pipes that connect to the radiator. I took the car to the shop and they fixed that problem easily. However, in the process, they found out that my O2 sensors needed replacement.
I would change them but the mechanic also said that the manifold is very rusted and could break in the process of changing the O2 sensor. According to him, if that broke, just the part alone would cost me $1700, not counting labor. So I decided not to change it, as it did not give me any problems before, like sputtering or low mileage.
As soon as I take the car out of the shop, it starts giving out signs of a bad O2 sensor.
I will get a new car and wanted to use my aveo as a part of the trade, but I think they wouldn't take it as it is, or would just gave me a very low quote on the car.

So, my question is: Does it take really all that money to change the manifold if it breaks, while changing the O2 sensors?
Should I really worry about it, since I am getting a new car?

Thank you very much for your help.
Pedro

Yeah this is a case of and other mechanic calling BS. Get a code scanner ODBII blue tooth and clear the codes before your trade in.

I am a little skeptical of this mechanic's story. If the manifold was rusty, I would use an acetylene torch to heat up the manifold around the sensor. As the sensor was suspected of being bad, it is expendable, cut off the back of the sensor and use a regular 6-point socket on it after the manifold is cherry red. Not the "split" sensor socket, a 6-point and some good leather gloves.

All 20/20 hindsight, but a manifold would have to be pretty rusty to be weakened. Aren't they made of cast iron? But anyhow, if the mechanic's warning there might be a problem says steps should be taken to not have a problem.

chuck / just my $0.02

ps: And "part alone would cost me $1700" ... really?