# Catalytic Converter Problem - O2 Sensor broke off



## pj94z (Jan 11, 2009)

My 04 Sentra 2.5 failed emissions. Check engine light was also on for a few weeks.

I took it to a local shop - they said it needs a new O2 sensor. They said it will run $270 to install an aftermarket one...i said ok...do it.

They call me back and say, well now, the catalytic converter is broken and I need to pay $1,300 for a new one. So, I went to see the car.

I saw that there is a hole on top of the Cat converter where the O2 sensor screws into. According to the shop, the O2 sensor started pulling out of the Cat Conv, making a circular hole in the Cat Converter. 

So, they said they can JB weld the new O2 sensor on there, so it stays in place...since there is no way to thread in the new one.

They are charging me $75 in labor for the weld...so about $350 total for everything. My car should be ready tomorrow morning.


Question:

will JB welding this hold it for the life of the car?

is there anything I should be aware of when I go pickup my car tomorrow?


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## rogoman (Dec 16, 2004)

Supposedly "JB weld " will withstand temperatures up 500 degrees F. CATs do get very hot. Hopefully it'll work OK for you.

$270 is very high for an O2 sensor for your car. They generally sell for $50.


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## pj94z (Jan 11, 2009)

rogoman said:


> Supposedly "JB weld " will withstand temperatures up 500 degrees F. CATs do get very hot. Hopefully it'll work OK for you.
> 
> $270 is very high for an O2 sensor for your car. They generally sell for $50.



Shop called me this morning and said JB weld did not hold - sensor popped out after driving car for 2 mins.

They are now going to do a "metal braid" weld which is supposed to be stronger.


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## metro273 (Sep 16, 2005)

rogoman said:


> They generally sell for $50.


For cheap aftermarket junk O2s.


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## vrefron (Dec 18, 2007)

Robo, JB weld will not hold because Cats DO get extremely hot...The hottest to the touch part on a warm car by a mile. The outside shell can reach 500 F easily. Trust me, I've burned myself on them many a time.

Edit: My brain read Robo's comment as "do _not_ get very hot", making me think him a moron. Oops.


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## sentraracer487 (Oct 14, 2008)

The whole point of a cat is to get very very hot the element of a cat is supposed to retain heat and cause any excess gas to burn off instead of going into the atmosphere. Im wondering however, what type of shop are you going to, i think you should find a more reputible shop, and possibly someone that specializes in exhausts. any other shop would just reweld a new bung in (you know welding, with a welder).


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