[emperus]

Trying to replace the Bank1 Sensor 1 O2 sensor on the 2.5L. I can see one if I'm looking from the top in the middle part of the enginge near the firewall. Is the the front 02 sensor?

Thanks

 

[yel-low]

Bank 1 sensor 1 is the one by the firewall. The uppermost one closest to your hood.

 

[emperus]

Bank 1 sensor 1 is the one by the firewall. The uppermost one closest to your hood.

Thanks. I can't seem to find one there. Could you give me a landmark on the engine where it would be near? Thanks.

 

[yel-low]

Trace your rear exhaust manifold down. The first O2 sensor you find it the one you are looking for.

 

[keninn]

the japanese follow the germans. since german cars are rhd, bank 1 is the driver's side. on a transverse engine, if you stand BEHIND the engine, then bank 1 is the right bank. which, in this case, would be the side closest to the firewall. the side closest to the radiator is bank 2. cyl 1 is always on bank 1.

 

[T2T]

the japanese follow the germans. since german cars are rhd, bank 1 is the driver's side. on a transverse engine, if you stand BEHIND the engine, then bank 1 is the right bank. which, in this case, would be the side closest to the firewall. the side closest to the radiator is bank 2. cyl 1 is always on bank 1.

Keninn, Thanks for the great information. Now, it will be easy to remember Bank1 and Bank 2 by just looking at the engine from the driver's side fender area ... and thinking in reverse, or right to left.

 

[emperus]

So, I had the manual, and kinda new where it was supposed to be. Couldn't see it, but traced the wire down. It was hidden behind a hose about 6 inches above the downstream (Sensor 2) sensor. Anyhow, tried removing it; tough going. Sprayed a lot of WD-40. Going to pick up a breaker bar some PB blaster and a 22 inch socket. The 02 socket I rented broke the wire part off the sensor. Anyhow, for those who replaced it, did you tackle it from the top or under the engine? And this was supposed to be an easy task. Thanks.

 

[T2T]

Do you have access to an Advance Auto Parts or Autozone? Both of those stores should have "loaner tools" for removing the O2 sensors. Usually, their tools are made of torque socket grade materials ... and not that chrome vanadium garbage as regular sockets are.

 

[emperus]

That's what I got. The problem is that the 02 sensor is in an odd positon and in an odd angle and I'm worried about stripping it in the process. Just going to pick up a lot of things and see what works best.

 

[keninn]

That's what I got. The problem is that the 02 sensor is in an odd positon and in an odd angle and I'm worried about stripping it in the process. Just going to pick up a lot of things and see what works best.

torch

 

[T2T]

When it comes time to installing the new O2 sensor, ensure you have some anti-seize compound to put on those threads.

 

[emperus]

Got it all sorted out. I thought I had the wrong O2 sensor orignially because the connection was different than the connections I saw online for the Bank1 Sensor 1 02 sensors. It had the same conection for the Bank 1 Sensor 2 sensors. Luckily I got the Bosch univesal sensor. Anyhow, the WD-40 did the trick and I didn't even need the breaker bar.

The Bosch sensor came with the anti-seize already on it. I added a little more though.

I am still a little confused as to why the connections were different.

Thanks for the all the help.

 

[GG Mazda3]

Removed