VW Beetle Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
89 Posts
Discussion Starter #1
Im trying to replace the o2 sensors in the car, more specifically the one in the front. where is it located? and is there a guide on how to replace it somewhere? i check the forums and google without much luck.

thanks
 

·
No one asked my opinion,
Joined
·
63 Posts
Lot of O2 stuff tonight...

I just did this last weekend. The front O2 sensor is located above the Cat to Manifold connection.

Here's how I did it:

1. Disconnect the front O2 sensor from the pigtail (mid body/passenger side, black box held on with 2 10MM plastic nuts). The front (pre-cat) sensor is the Black connector)

2. Drop the Catalytic Convertor at the Manifold (if $$$ permit, replace it). There are six nuts holding it to the manifold. Soak them in WD40. Back em out a little, shoot them again, back them in and them out again. The middle nut towards the front of the engine can be gotten off by sticking your extension (you WILL need at least 10 inches of extension) through the Cat tubes, then attach your socket to the extension sticking through the tubes. A knuckle makes the job easier.

3. You can now access the O2 sensor. It's a big SOB, I think it may be a 21 or 22. I used a big crescent wrench, it came out easy. The pig tail makes turning it difficult, you can cut the old pig tail off to make removal easier, but installing requires that you twist the pigtail as the O2 sensor backs in. Be patient.

4. Put the cat back on (use a new gasket), hook the O2 sensor back up to the plug and you are back in business.

Note: If you replace the Cat, you'll have to pull the Heat Shield between the Body and Cat to be able to pull the cat.

Good Luck
 

·
Premium Member
Joined
·
324 Posts
I recently replaced my front O2 sensor, but I accessed it from the top:

1. as above
2. Remove windscreen wipers and black plastic rain cover
3. remove the black metal shield
4. remove engine cover
5. Access O2 sensor. I bought a special socket, see attached file. It allows you to use a normal sochet wrench without damaging the cable.
6. Do steps 4 to 1 in reverse order.

it's not too hard, but kinda difficult to access. If accessing from the top please don't forget to either cover the paint or wear clothes without metal parts. You don't want to grind the paint with your belt.
 

Attachments

·
Bug me again!
Joined
·
2,758 Posts
When my b/f did it, no way did he drop the cat. He used some heat to free up the sensor, but other than that it was easy.
 

·
ToD Maiden Voyager
Joined
·
4,916 Posts
Good thread. I need to do this to mine as well and need to do it from the topside. And was also considering buying the removal tool as well. Did anyone per chance take pics they could post?
 

·
.
Joined
·
2,646 Posts
It is NOT necessary to drop the cat. That poster made the job way more difficult than it needed to be. Go to an AutoZone or Advanced Auto, or the like and buy the special O2 sensor socket. I have one slightly different than the picture of the one posted--it is shorter and more like a "crows foot" if you are familiar w/ that tool. I have replaced the front sensor on a 2.0L so I know the job you are in for........Enjoy!;)
 

·
No one asked my opinion,
Joined
·
63 Posts
I chose to drop the cat since I was getting symptoms of a bad cat. Dropping the cat really isn't that hard. I had it out and back in (including splicing the pig tail to the generic Bosch O2 sensor) in less than an hour and a half.

With the Cat out, there is plenty of space to work.
 

·
Registered
Joined
·
105 Posts
I recently replaced my front O2 sensor, but I accessed it from the top:

1. as above
2. Remove windscreen wipers and black plastic rain cover
3. remove the black metal shield
4. remove engine cover
5. Access O2 sensor. I bought a special socket, see attached file. It allows you to use a normal sochet wrench without damaging the cable.
6. Do steps 4 to 1 in reverse order.

it's not too hard, but kinda difficult to access. If accessing from the top please don't forget to either cover the paint or wear clothes without metal parts. You don't want to grind the paint with your belt.
Thanks. Inspired by your steps, I managed to change my pre-cat O2 sensor without dropping the catalytic converter AND without remove the rain cover & black metal shield. Here's my steps:

1. Drive the car onto a ramp.
2. Remove engine cover.
3. Push aside the hose connected to coolant tank.
4. Examine the position of O2 sensor. You need good lighting condition. Put your head around coolant tank position, and you may be able see O2 sensor sits within a metal case. See attached image I borrowed from "montoya 01 2.0".
5. Use a special O2 socket (see attached image, only this works from my 2001 2.0L AVH), an extension, a ratchet to loose the old O2 sensor.
6. Go to the bottom of the car, disconnect the front O2 sensor from the pigtail.
7. Trace along the cable up to the sensor, remember how the cable goes. I encountered 4 clips, open them.
8. Take out the old sensor from the top and put in the new sensor. Tighten it.
9. From the bottom of the car, route the cable as the old cable did. Close those clips as you encounter them.
10. Reconnect the O2 sensor.

Note:
  • step 4 is quite difficult. You need to have a long arm, and should protect you back of left hand as going deep.
  • step 5, a normal ratchet can drive the funny O2 socket which has a 8-tooth star-like female (it's actually is not a star! I took me 2 hours to find a matched male "star"). I think it's just composed of two identical square holes.
  • step 7 appears difficult (so some people may want to unload the underneath protective cover and the catalytic converter, which is not needed), but you can trace the cable by pulling it, and look from various angles. I found that put your head around left wheel will give a good perspective.
 

Attachments

1 - 10 of 10 Posts
Top