Ordered a replacement sensor from Aaron's Subaru parts. Quite a tight spot to get to, to replace this. Anybody remember what tool they used to get in there, or what they had to remove to make the job easiest?

 

Looks like the sensor is 19mm. Thought maybe a crow's foot wrench might work. But before I go buy one thought I'd seek advice. Thanks in advance.

You'll probably need to remove the PCV tree off the block, that's the only way I was able to get a socket in there.

 

Be careful with the connector on the harness end! I snapped off the little latch on mine removing it, now it's just sitting there on the sensor with good grace :-\