Hello, I recently purchased a 2012 Nissan Altima from my Dad. It has about 155k miles on it and had the transmission replaced at 142k miles. He has kept up with its regular maintenance (we had the car inspected twice by PA state and a trusted mechanic before the purchase), and the vehicle is in excellent condition; however, I recently got a P0420 code for the Catalytic Converter. When taking it to the dealer, they said the front and rear Oxygen sensors needed replacement and that there was an "internal failure" in the Converter. The repair would cost $4500 from a dealer, which is the price I got the car. I have 3 key questions: Is the Lacquer Thinner method safe on this vehicle, and how much is the proper price (specifically in Jersey)? Can I replace to O2 sensors myself?
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trusted mechanic
Take the car here instead of a dealership. For 4500 you can almost get an entire engine.
Answering your questions:
1. No, can damage your engine and fuel system.
2. Depends what's really wrong, needs a proper diagnoses. Could be O2 sensors (cheap), could be a bad cat (expensive). It also depends how many cats there are.
3. Getting to an O2 sensor is usually simple, the issue is that it can be very difficult to actually get out of the exhaust. Its been in there for 11 years, and gone 150K miles, its almost welded in there. You'll need to pre-soak it with some PB blaster or something. Obviously, only do this when the exhaust is cold.
Don’t try the lacquer thinner. Imho, it can cause more harm than good.
The P0420 code can possibly be upstream or downstream from the cat, or it can be the cat itself. More likely than not, it is the cat (judging from P0420 codes I have had on two cars.)
Obviously, first try to verify the actual problem. If you have trouble accelerating uphill, or trouble accelerating at all, it is most likely the cat.
If it is the cat, it may be more cost effective to go to a muffler shop than a dealer.
