Roly Baldwin

I spent some time today attempting to remove the O2 sensor on a 90 C2. I think it must be the original since it REALLY doesn't want to come out.

I have:

- soaked with penetrating oil for several hours
- tried using a ring spanner
- tried using a blunt chisel and hammer
- tried using stilsons (pipe wrench)

...but it doesn't want to know.

Any suggestions? Please don't tell me it's a left hand thread.

The 'nut' is now very round so I doubt a socket will fit on any more (if I cut the top off)...

Bill Gregory

They can be quite stubborn. At this point, I'd file the nut so you can get a wrench on it, and use heat (propane or other gas torch) at the juncture where the O2 sensor screws in. When good and hot, put the wrench on it to break it's grip.

Roly Baldwin

Bill,

Thanks - do you think one of those throw-away torches with a small gas canistor will do the trick?

horst

How about jacking it up, removing the left rear wheel, and running the engine a few minutes, and then trying? As a last resort, take the whole damn thing off, and take it to a machine shop.

Richard Talbot

Hi,
change one on ours 3 months ago, blow torch did the trick to remove, but when you have removed it take a flashlight and look into hole, I needed to clean out thread with a piece of wire as some of old sensors thread was left in hole

cheers

Ade - C4 91

Yep, needs to be cherry red before it will remove cleanly, please don't try to chisel it off as you may damage the Cat. The thread may need cleaning as Richard suggests.

The newer sensor should come with some anti-seize compound on the thread, so don't use any additional lubricants (especially silicone grease) and don't get the tip contaminated as it will stop the sensor working.

Ade.

964porschedude

DON"T USE LEAD PASTE! If you do it will contaminate the O2 Sensor and CAT. Try some copper brake paste or some Graphite Sparkplug anti-sieze.

Keith

Kahdmus

Where is the O2 sensor? I realize "where" in terms of exhaust and what its function is, but more toward literally how do you access it?( Picture a bonus!)


OH, and BTW, I've read Adrians book pages 142-164 (or whichever address it) and done a couple of searches!

Richard Curtis

In my experience, removing O2 sensors in any car is difficult. After much soaking in penetrating oil (some are much, much better than others. I've found a product called FreeAll to be superior), try working the sensor both forward (tightening) and then backward (loosening). Alternate these efforts. You might consider using a long breaker bar on the socket (assuming you can now get a socket on it) or an extension on your ratchet. Sometimes this works. I've also been successful using a boxed-end wrench (spanner), again doing the back and forth movement. Hope this helps.

Kahdmus

Richard. This is a year old thread, hopefully the initial question got answered and if I have to do this I will certainly use the tips! Thanks!

What I am trying to find out here is where is the O2 sensor? (I realize "where" in terms of exhaust and what its function is) but more toward literally how do you access it?

Thanks

rsa

Hi Howard,

The O2 sensor screws into the top of the catalytic converter (right hand thread). Access at left side rear wheel. Easier to get at if you remove the wheel.

I tried like hell this spring to remove mine from a bypass pipe so I could reinstall my cat for smog check. Tried lubes, heating to white hot with blow torch etc. Ultimately had to have a shop cut it out and install a new sensor.

JasonAndreas

Here's one way of accessing the O2 sensor, removing the rear tire would have been a little easier.

Kahdmus

PERFECT!!!! Thank you sir!!!

BGLeduc

Not having looked yet, is getting to the connector in the engine bay any particular problem?

My current sensor is the Bosch unit spliced to the Porsche harness. In heavy rain (fortunately rare where I live), I have had some severe stumbling, and Adrian (and others) have suggested that the Bosch is not properly waterproof, and prone to causing that sort of problem. So, I have a new Genuine Porsche O2 sensor ready to go.

I have my fingers crossed that the current sensor, having only been in place for a couple years, may come out without drastic measures, but I am concerned about access to the plug connection.

BGL

Johan K

The o2 connector is easy to reach on the left side inside the engine bay, with one hand that is. In order to be able to connect/disconnect the o2 sensor you need to use both hands. Best way to achieve this is to remove the rear blower fan. Then it´s easy-peacy. The rear blower fan is mounted with two bolts only. You will also have to disconnect the heating ducts. The job is a 10 min effort, tops. I however managed to reach the o2 connector with both hands without removing the rear blower fan. Do not ask me how, but it worked.