03 v70 non-turbo catalytic converter

[RickHaleParker]

Thanks for all the suggestions. Been reading that the rear O2 sesnor is a pain to remove. Any recommendations on how to remove?

Brush off rust and long soak in penetrating oil. Remove with a Oxygen Sensor Socket so that you do not round off the corners of the hexagon.

[amblerman]

Thanks for all the suggestions. Been reading that the rear O2 sesnor is a pain to remove. Any recommendations on how to remove?

Brush off rust and long soak in penetrating oil. Remove with a Oxygen Sensor Socket so that you do not round off the corners of the hexagon.

And use a proper O2 sensor wrench/socket.
There are many types, but I have settled on this type:
Note, I am fairly sure all O2 sensors are the same size (ie 22 mm). But I can't claim to know this for sure. The reason I like this style is the offset of the socket attachment allows for more flexibility when trying to maneuver around things that might be in your way. The fact that this style is open on top deals better with the O2 sensor cable vs the other style which looks like a regular socket with a slit up one side.

O2socket.png (80.21 KiB) Viewed 788 times

[RickHaleParker]

Note, I am fairly sure all O2 sensors are the same size (ie 22 mm). But I can't claim to know this for sure.

They are all 7/8" (22mm).

[- Pete -]

Thanks for all the suggestions. Been reading that the rear O2 sensor is a pain to remove. Any recommendations on how to remove?

Biggertuna - Is your rear O2 still working? I'm assuming it probably is, if your cat is the thing in question.
Might want to be careful with penetrating oils around a still-good O2. I've had bad experiences with O2 sensors being ruined from using penetrants. Not refuting Rick, but if it was me, I would try it dry & hopefully save yourself the possible cost of a downstream O2.

Also, you will be happiest with the offset O2 socket like Amblerman shared. In fact, I don't think the regular socket-with-slit-up-the-side will even work, unless its a very deep socket. I have both sockets & the offset was the only one that would accommodate the O2 sensors used in these.

I've done about 8 O2 sensors in the last month and I would have to say that both upstream & downstream are about equal. Not difficult, but for each you will need to remove some stuff to gain better access. Granted, your N/A is different, but still will have 2 O2's. For the downstream one (cat mounted), It'll be easiest if you separate the cat-back section of the exhaust from your downpipe. This may require you to cut the old crusty flange fasteners & maybe drill out any remnants stuck in the flange holes. Then, with the downpipe still attached up top, let the cat sag down & use your O2 socket, 3/8-1/2 adapter & a breaker bar or big 1/2 ratchet & bust it loose. For this part I usually have the handle end of the ratchet/breaker bar pointing down the tunnel, towards the rear of the car. Hold the cat flange with your left hand & give the ratchet handle hell with your right. It'll break loose right about the time you're about to let off.

On all the P2 O2's I've done it's been 3.5 turns counterclockwise and the sensor is free from the bung. You'll want to be cognizant of this turn count. When you go to reinstall the O2, get it ready by spinning it 3.5 turns CCW before threading it into the bung. CCW vantage point being the top/wire end of the O2 sensor. This way your wires aren't all bunched up & spiraled once the O2 sensor is tight. You will probably also want to have some gasket material ready to make a new DP/catback exhaust gasket, or get one online. IPD has them for $5 - LINK HERE. When I was digging up the IPD link I came across this one, says it fits pretty much all P2's & way cheaper (buy a few) - https://www.eeuroparts.com/Parts/52984/ ... -25439056/
On turbo models there's a gasket up top (type depends on year) where the DP meets the turbo. I'd check to see what your 2.4 N/A need's.

[Biggertuna]

Took off the catalytic converter this afternoon. Not too bad of a job. After taking off the downstream O2 sensor, I tilted the cat like a seesaw and sure enough, I saw a honeycomb/mesh piece move back and forth. Seems like there are several rows of these and from what I can tell, there are a couple that are not attached and moving around the chamber (based on sound).

Sounds like it's time for a new cat.

[abscate]

Late to this job but I did a front OXS over weekend. Three cycles of 60 second beating and cooling won propane and it pulled out easily with the Tekton socket

[oragex]

Look up Ebay, but try not buying the cheapest because many of these have fitment problems - were not welded in the correct position. I'm also looking for one so if you find a seller with a good part, let me know here. Magnaflow should be good but it's $700

[RickHaleParker]

Magnaflow should be good but it's $700

Two weeks ago there where MagnaFlow 51660 on eBay for just under $500.00 ( Direct fit OEM grade for 03 V70 NA ). How they are threading at $669.78.

[SuperHerman]

Sounds like your cat is past its useful life. As mentioned in my prior post, on my 2001 XC70 I used an Eastern. Fit and performed without issues. Rockauto has the Eastern for about $305 plus shipping. I tried a Bosal on an Audi a few years back and didn't find the quality better than the Eastern - although it worked just fine.

If you have time and any welding skill - you can by a generic and weld it in. It will take some research to find the right one, but it is by far the cheapest way to go.

[oragex]

The 51660 got more expensive 4 some reason indeed
There's a 24133 ULEV for $420 but the secondary O2 sensor is not at the right location
For turbo it's cheaper 23199 at $470

They also sell the catalytic converter alone for well under $200, just need to find out the O2 hole dia (18mm?) and the pipe size (I "think" the exhaust for non turbo is about 2.3in OD so "perhaps" a 2.5in ID cat would do). But like you said, it takes serious welding fitment skills to position it perfectly so it won't stress the flex downpipe otherwise the flex will start leaking (had this problem). So it's better to bring it to a good exhaust shop. But since one may also want to replace the flex while there because it's old, it's better to go with the whole section and no fitment worries (cheap ones all have fitment issues)