found this little guy hanging on for dear life

My 2.4L '95 Tacoma started to make a noise as if the muffler was no longer functioning. When I accelerated it sounded like I had one of those noise amplifier on my exhaust.

This is what I found when I checked around it:



It's located towards the passenger side and I believe that pipe leads to the muffler.

I am pretty sure I've had this issue with it before. I'm going to go through my repair receipts to see what it was. The mechanic had said (this was around 2 years ago) it was either going to need to be replaced or fixed. I'm pretty sure he just put it back together.

So what am I looking at?

Interestingly both times this problem happened it was following a rainstorm. Not sure what if any role that played.

 

O2 sensor.

 

That is an O2 sensors that lost it's bolts and fell out, you can see the flange I the upper left of your picture. Some high temp loctite and new bolts should solve that issue.

 

Ok yea I do see how they would fit together. I'm not an expert when it comes to mechanical work but if I have the tools and a decent youtube guide I do manage my fair share of repairs. Is this an easy enough DIY project?

 

o2 is just a matter of bolting it back on. get a gasket at autoparts store. your hanger is broken off and will need to be welded back on though.

 

Looks like it would not hurt to run a die on the threads. Check if a gasket is required.

 

As always, this place provides great advice and information. Thanks!

Random observation: I had to drive home from work with this issue. I don't know if it's a placebo effect type deal but I could have sworn I was getting better acceleration with the noise.

 

Butt Dyno calibration error. My Rallycross car felt a lot faster with a cat delete too

 

I can see this now those studs are so rusted I have no idea if there was nuts on there how they would come off.

Maybe the pictures make them look worse then they are .

Getting new ones on will be interesting .

If this was mine it would turn into a project.

Is not your check engine light on??

 

Yes, the nuts usually go first (fortunately), leaving the stud. You will need to run a die down over the studs to clean them up before attempting to install new nuts.

 

Yea, the check engine light has been on for a couple years now.

I'm pretty sure what you and a couple of other posters have mentioned here is true, that the studs are probably no good.

What's the best way to attack this? I found the gasket that I will need at advance auto (https://shop.advanceautoparts.com/p/dorman-help-gasket-for-oxygen-sensor-47021/22147944-P?navigationPath=L1*14932|L2*16465|L3*16466)

I am searching for the proper nuts. Are they called O2 sensor bungs? That's a term I've seen and the pics of it look about right.

If the studs are shot, is there any other method I can use to have the O2 sensor stay in place without getting a specialized tool?

 

I would first try to run a thread die down the existing studs. I think you will be surprised how much of the stud (and threads) are intact. The old nuts almost disintegrate over time, which actually makes it easier, since you don't have to get the remnants off the studs. Those nuts are a standard metric size. You can pick them up at Home Depot, Lowes, Tractor Supply, etc. Even if you don't presently have a set of metric taps and dies, it is a great investment to make, for the long haul of doing maintenance. The term bung refers to the whole piece that is welded to the pipe, which would include the studs. Best of Luck!!

 

For my money, a piece of 12 ga copper house wire around the pipe and both hangers on the frame, and twisted tight is a quick, and low cost alternative to trying to get the pipe hanger welded back on the pipe. And the copper wire will last as long as the truck.

 

Just to confirm, the nut size for this is going to be 13mm right?

I searched on here and it seems that rear O2 sensor nut size is 13mm but couldn't find a definitive answer for the 'front' one.

 

^historic license plates

 

M8x1.25 If you get JIS nuts they will be 12mm across the flats ( Japanese Industrial Standard)

DIN nuts will be 13 MM across the Flats

 

Had my O2 sensor nuts rust off on my old '97 TRD. The sensor is probably OK, but your MIL should be lit. Get some nuts , a gasket, and put her back on. Clean up those treads first, and wire up that exhaust pipe.

 

At least your O2 sensor came out easily.