Would the front oxygen sensor be easier to change with the engine out? I'm getting the head gaskets and clutch done on my 2000 OBW with 157,000. The oxygen sensors have never been replaced and I know that at least the front one needs is overdue to go out at any time. I have an OEM sensor. Should I give it the mechanic to change? Or should I save the labor $ and do it myself? It's pretty easy and and 20-30 min job isn't it?

mmm...I don't think it would be any easier with the engine out. The engine really isn't in the way of changing the front o2 sensor.

 

Make sure to get an OEM sensor for the front; no aftermarket on this one. This is a 5 wire sensor on a 6 position connector. Some '00obws had the front o2 sensor replaced or replacable under recall; so you might want to check that out.

Changing the front O2 sensor is very easy. But you definitely need to get the OEM sensor. It is just PnP simple! I got my front sensor from the dealer for about $78.

For the 2000 OBW with manual transmission though the OEM front o2 sensor is going to run more like $130. I see the OP has already procured the OEM sensor...excellent!

 

22641AA00A OXYGEN SENSOR FRONT, A/F FOR 2000-2001 MANUAL TRANS LEGACY OUTBACK (non-H6)(only for vehicles with 2 sensors, this one is in the front cat)

 

The one for auto trans is about $74; I think it's so much less because there was the recall on the front o2 sensors for auto trans tip cracking off and getting lodged in the cat, so Subaru probably got a good deal on the huge quantity of that particular sensor needed to handle the replacements.