I have a 2005 2.5 SL Altima that started missing like my plugs were bad. I had just had them replaced, so I took it to the dealership to see what the problem was. They told me that my Catalytic converter had failed, and that fragments of this had then went into my engine knocking around and tearing the valves, and everything else up inside the engine. The piece's were so big that they were bouncing on the piston and hitting the sparkplug literally bending it to where there was no gap at all on the plug. I have put up pictures, and kept pieces of the the debris the Catalytic converter threw in my engine when it failed. Nissan told me that I would need to get my engine, upper intake, and head rebuilt. Plus the new Catalytic Converter. They wanted $5,300 to rebuild the engine. I ended up finding a guy that would do it for $3,500. Unbelievable that a major car company can get away with knowing about a major problem, and doing nothing about it. I tried claiming with Nissan consumer affairs, and they told me that the Catalytic converter was only warrantied to 80,000 miles, and that they could do nothing for me. I always took my car to the dealership to have it worked on, and had a extended warranty to 108,000 miles. Why didn't they fix the catalytic converter before I had this problem under warranty the times I had taken it in before. There was no check engine light or warning when this happened. How are you supposed to know when to change the converter? If it's supposed to be changed when the 80,000 miles had been reached why didn't one of the Nissan Technicians fix it under my extened warranty. Why was the converter left until it caused thousands in repairs!! I had been in there numerous times before this happened to have engine mounts, tie rods, headlights, break lights, and numerous other things fixed. I had even been in to the Nissan service to have some work done a few months before the engine failure, and not a word about how I should replace the cat. converter. Then when I bring it into the shop when the engine is blown. Nissan Service, all of the sudden know's all about this issue with the converter, and the engine failure it causes. Ridiculous!!! So not only can you not trust Nissan to put out a reliable product in this Altima, you can't trust Nissan Service to warn you about the problem. Or Nissan to admit when they made a mistake, and fix it. This cost me time, and a lot of money!!

I purchased a 05' altima form the dealer in '05 adn my check engine light came on in Oct'08 they told me that it was my catalytic converter. They never told me that they were having problems with this part and now in March'10 I noticed that after receving a oil change 2 weeks ago my car had no oil then I noticed my car started blowing cool air when it was idiling now nissan is telling me that the catalyst converter went again and is now in my engine and I need a new engine at $4,5000. No check engine light came on I mean nothing at all. So how was I supposed to know something was wrong.

I have since contacted a lawyer and wainting to hear back from this because Nissan isn't willing to take owenership for this problem