2001 V70 Front Oxygen Sensor Removal Advice?

skaupert · Post by **skaupert** » 23 Jan 2010, 08:57

I'm looking for advice for removing the front oxygen sensor, the one that sits in the exhaust manifold. It seems pretty well fused into the thread.

The sensor that's in there may or may not be faulty, so I don't want to cut the wires at this point, which means no use of a socket and a long handle. Applied Liquid Wrench, but the hard part has been to apply enough force to break the bond.

Thanks.

JohnInFlorida · Post by **JohnInFlorida** » 23 Jan 2010, 09:13

I bought the upstream sensor for my S70 at Autohaus and had PepBoys put it in for $80. They don't guarantee the part but that is OK for me. My car is running great now. The strong smell at the exhaust pipe is gone and it is running very nicely down the highway.

2000 S70, 200k miles

Post by **JDS60R** » 23 Jan 2010, 11:01

You can buy a oxygen sensor socket at harbor freight for about $4. They have a slot in the side so you do not have to cut the wires.

You have already applied the penetrant so now is the time to turn it. If it comes out easily then you are set. If it is not turning out and the corners are begining to round over just stop and take it to a shop.

I remove them with a long 6 sided closed end wrench and a 3 lb hammer to impact the wrench. Do not use a 12 sided wrench as it will just round off the corners. If it won't move with the closed end wrench (22mm or 7/8 in is the standard) then its best to go to a shop.

If you are a home mechanic then break out the torch and get the bung orange -then cool down with the wet rag and penetrant. In the worst cases I sometimes have to turn them out while the bung is still hot. If that doesnt get it then replace the pipe or bung. Always use enough antisieze to cover the threads but do not allow it on the sensor itself.

Amazon sells the Bosch direct fit pretty cheap but make sure you verify that you have the right part before you order. Some of the AMazon fitment search engines are wrong but most order sites are correct. Best to know the part number of what you have.

At 100k miles the sensor may still be working but it is doubtfull the reading is actually correct. They do wear and 100K on a good running motor seems to be when the accuracy falls off. I have taken them out of cars with 300K and they still function timely but are not accurate. The MPG increase is worth the trouble of getting them out.

skaupert · Post by **skaupert** » 23 Jan 2010, 17:59

Done.

I had already bought the Denso OEM replacement sensor on Amazon (148.71 plus tax and shipping). Bosch was around 125, but I followed ipd's indication that the Denso is the proper one. It sure matched the old one that I pulled out.

I had unscrewed the cross brace left and right (but not in the middle), and turned it ccw just enough to increase access to the area behind the engine, which made it a lot easier to work.

I used a regular 7/8" open wrench (didn't have a 22mm), and applied Liquid Wrench again just before (first application was almost a week ago).

After trying to concoct some scheme to increase leverage, I decided to give it another try just using the wrench. Note that there isn't really room for any extension. This time it worked. The thread looked pretty good. I used a wire brush to clean any loose stuff out of the thread.

Then I applied the anti-seize compound that comes with the Denso sensor. I did that very carefully to make sure that a. nothing got on the sensor itself, and b. the thread would be completely covered.

When everything was hooked up again, I disconnected the battery for about 15 minutes to clear out the ECM.

For the moment the check engine light is off.