I would just add - there is probably no need to remove the Y pipe or the top half of the air box.

Just remove the covers, the MAF and associated flexable pipe and the auxiliary air hose.

The whole job should only take about 1 hour for both - once have done them a couple of times!

 

Thank you so much for creating this tutorial - it's going to save me a ton of frustration! You rock!

 

lol you're welcome my friend

 

Great tutorial. I got mine done in about two hours and no more check engine light!

Thanks
Mike

 

Wow, this seriously will come in handy when I need it. A job well done. I also like the fact that it's a TIP as well. Some things are different from the TIP to the Manual as you guys already know.

 

I got everything done but installing the new O2 sensor on the pre-cat driver side.. wow PITA is a wild understatement. I can't even get the new one in there. Theres no wiggle room whatsoever and even for a guy with smaller wrists it seems impossible. You guys had to have removed some more parts/hoses to do that part, didnt you???!?

 

Thanks for doing this write up, came in handy today as I changed my pre cat sensors. Passenger side took like 15 minutes to remove and replace. The drivers side about 15 minutes to remove, but I will be damned if I can't get the new one back in! Not much room in there to get a grip on the sensor to get any turns on it. I event tried using a 2 foot piece of rubber hose with the sensor stuck in the end but couldn't get it started. Any tips out there? I have a 2001 A6 2.7T just like this thready. I walked away after an hour and figured would get back at it in the morning.

 

Well, I went back at it fresh this morning and was able to get it started by hand after stretching my arm down as far as I could possibly go. Once the threads got started, the O2 sensor tool made short work of getting it tightened up.

 

Just wanted to say thanks! Did the passenger side pre-cat today.

Attacking it from the right angle makes all the difference.

 

I have performed this operation twice now, specifically Bank 2 sensor 1 drivers side pre cat. Neither time did I remove the Y pipe or some of the other parts you removed.

I remove the screws for the coolant reservoir and move it out of the way but leaving all the hoses attached. I pull the O2 connector and the wire/connector next to it on the fire wall out of the bracket and move them aside. Unsnap the heat wrap around the wires so you can remove the O2 sensor/wire. This gives ME (if you have bigger forearms you may be hampered) enough space to reach down and slide the crows foot over the sensor. I then use a combination of extensions with a u joint and wobbler on the end, you can almost get a straight shot from the passenger side if you put the extensions between the two hoses just above the sensor and in the line of site from the passenger side. Follow the instructions to douse with PB break (I have yet to find anything better) I also start with a cold car but run it for about two minutes to put some heat into the manifold to help free the sensor. Once free, I use the wire itslf to spin the sensor out of the bung with a little help from my hand.

I have also used the universal Bosch O2 sensor which you have to splice into the oem plug of the old sensor, it is both simple and robust and will save you in the neighborhood of $50.

Hope this helps.