Downstream o2 sensor replacement

I need to replace the downstream o2 sensors on my 03 tundra. The upstream ones were done 30000 miles ago. Any tips or suggestions..I'm mechanically familiar with the truck, but I'm wondering if I will need to put heat on them to break them loose ( I don't have a torch). They are original 160,000.

 

I’d say not likely. I’m at about 130k and just flipped mine from side to side yesterday due to low voltage on one side. Two 12mm nuts per side and the sensor clip that you’ll have to undo. The clips were more of a pain than anything. Hopefully this won’t be too big of a deal for you.

 

Whether you need heat/penetrant really is a matter of where you live and how many miles on the truck.

I know it's not in everyone's budget, but I always recommend replacing them in upstream/downstream pairs. This is one of those parts you want to use Denso brand (OEM off-market), and be careful to look up your part numbers for "exact fit" sensors at www.densoautoparts.com, noting that RWD and 4WD trucks sometimes use different sensors.

 

Thank you

 

Pics? If the nuts look half disolved from corrosion, a nut splitter might be a better idea. That’s what I did with my first set.

The 2nd set still had plenty of the nut left, so I spun them off with an impact gun and a universal wobble extension to get the socket in there.

 

I need to do this on my last remaining original downstream. I'm worried that the "shield" around the sensor would be in the way of a splitter. Do you remember what yours looked like/still have it?

 

IIRC, I did what I could with a nut splitter and cold chiseled the rest. Most of it was dissolved already. Didn't even resemble a nut IMO.

The 2nd time around, I got rid of those "shields" as they only get in the way. Hasn't caused any issues yet, but I don't go off-roading regularly where a rock might hit them. BTW, if you mangle the threads, you can get another stud to put in it's place. I had to do that the first time. It doesn't have a part number but the dealership is generally able to match it if you bring in the old one.

 

Hmm I suppose I could just go old school with a sharp chisel. There isn't much left on the one that's holding me back. The other nut on that sensor had dissolved completely. I got the ones on the other sensor with needle nose vise grips but haven't had any luck with the other side.

I got 3 sensors done and have no check engine light so I've just been letting it ride.

 

When I had to do this, the nuts on the downstream sensors had pretty much disintegrated. In fact, the reason it was throwing a code at all was because of a leak between the sensor and gasket that opened up after the nut was gone. I used a small Dremel cut off wheel to remove the remaining bit of nuts. Miraculously, the studs were still good, although I did have to chase the threads a bit.

 

same here on my 2002. Ran a die down the studs to clear any other debrizzle, and then put stainless hardware (Nut, lock washer, and flat washer) where mild steel had only gone before