ISFFUN

iTrader: (4)

I'm trying to replace my sub-o2 sensor that is connected to the cat. The problem is I can't get any sockets on it, or I'm not sure how to even get it off. It's a bit rusted, but it also looks like it's one of those nuts that is welded on. I don't know. See the picture below. I also tried spraying rust-remover/unfreezer etc.

MrBrock

Try to knock off as much rust as you can with a wire brush or something and then heat em up with a torch. MAP gas works great, burns hotter than propane and canisters fit on propane torches, comes in a yellow canister. PB Blaster is about the best penetrating oil I've used, that'll help too. Good luck

ISFFUN

iTrader: (4)

Thank you.

If these weren't covered in rust, are they normal 10mm nuts? Better yet, does anyone had a picture of this area from their own car?

Ali SC3

iTrader: (10)

they will be like 10mm or 12mm but they are sort of tapered and the rust will basically make the bigger socket feel snug until you put some force on it and strip it.
best bet it using pb-blaster, getting it as clean as possible with a brush, heat the bolt up either with a torch or if you are lazy just run the car for like 20 minutes and then get under there and wrench it off. Be careful if you use the engine running method as everything will be hot. the torch is better if you have it but either way should work.

if all else fails get a dremel or sawzall and cut the bolts right off. Im not sure how easy it will be to put another one back in though.

ISFFUN

iTrader: (4)

Well! After spraying and brushing the sh* out of the nuts I got them off using a 11mm socket and it coupled (dunno what to call the contact point) at the back of the nut. The front of the nut (the smaller part) was nearly rusted away, only little fragments of it remained. When I replace the sensor I'll need to repalce the gasket and the nuts.

Bad news: I bought the wrong O2 sensor. It was for a SC400, non-flange type.

I tested the other two sensors with a multimeter based on the repair manual specs and both #2 and #3 read 5 ohm, which is almost in line with specification (5.1 - 6) but #1 was close to 5.7 ohm so I figured #2 was bad as well and replaced it. I hope the O2 sensor works the same.

I got the #2 O2 sensor out with a 7/8 wrench and put in the new Denso one with the provided anti-seize compound.

So thanks for all the input, it helped! If you have any knowledge about using the sensor with the SC400 part number in the SC300 please advise. It seems to be fine and the socket and wire colors/layout are the same.