how to locate and replace my oxygen sensor?

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skittishsynapses
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how to locate and replace my oxygen sensor?

Post by skittishsynapses »

I'm rather new to the idea of working on a car. My girlfriend grew up where everything is diy, so she's been the driving force for doing work on my '87 cabby. We've purchased the Bentley manual and we've been doing work on the car whenever necessary. As a student, I don't have much to spend so I've had to work on Betsy (the cabby came with a name from a previous owner) in bits and pieces.

We've been planning on changing out the oxygen sensor for a while, but it wasn't quite a priority until recently where my poor car worked itself going up into a mountain area and the oil pan bolt loosened, dripping out half of the engine's oil in a few hour's time.

(The bolt had loosened because a friend of ours overtightened the bolt, stripping the threading on the oil pan a few oil changes ago. Replacing the pan, gasket and bolt on friday.)

The oil smelled heavily of gas. nothing cloudy, creamy or off colored. It's smelled that way for an couple oil changes now. We're guessing there's too much fuel in the fuel to air mixture. Now, where's the question in all this? haha.

Okay, so after looking at the Bentley, we can't quite pinpoint where the oxygen sensor is located. I found some photos on this site:

http://www.geocities.com/jonnyguru/vw/o2.html

but don't know if that applies to my car's year. Even then we're fuzzy as to where the oxygen sensor is. would anyone have any photos up we can look at? Oh, and would anyone know of any installation guides online?

I'm sure we'll have more questions about the senor later but for now, these are the important ones! thank you!

- Jonathan
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Re: how to locate and replace my oxygen sensor?

Post by CalAltaDubber »

Hello Johnathan, and welcome to TRF.

I realize that some of these things are a little scary at first, but the nice thing about VWs is that they are pretty common.

The pictures in the link you gave are good, but the author didn't explain whare to look very well.

The connector he shows in the first picture is a little hidden but facing the front of the car look at the side of the engine on your left hand side. There you will see an electrical connector attached to the engine (it should be blue). That is the cold start valve. Under the valve and a bit closer to the fire wall you should find a bunch of wires. That is where you will find the connector for the O2 Sensor.

This picture shows both the Cold Start Valve (the blue thing) and the O2 Sensor connector.

Image

The sensor itself is located on the exaust manifol on the back of the engine.

Again standing in front of the car, you will see a long black plastic tube, that has a couple of bends in it. It runs from the fuel distributer (on your right hand side) to the throttle body on the intake manifold. If you remove the tube, you should be able to see (and access) the sensor by looking below the intake manifold. It is the thing sticking out of the exaust manifold that you see in the middle of this picture.

Image

Feel free to ask questions here any time. All we ask is that you post some pictures of your car from time to time.
Phil

'87 Cabriolet, "Topless Bunny"
'88 Cabriolet, "Posh Bunny"
'04 Golf
'12 Golf Wagon TDI
'69 Manx type Dune Buggy (New Toy)

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Re: how to locate and replace my oxygen sensor?

Post by sixsracing »

A little smell of fuel in the crankcase oil is fairly normal with high mileage. (100k plus)

If it's very noticeable then I would be taking a closer look at the fuel injectors too.
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Re: how to locate and replace my oxygen sensor?

Post by kamzcab86 »

After replacing the OXS, be sure to check the duty cycle and adjust the air-fuel mixture and/or idle as need be: http://cabby-info.com/cis . :beer:

And welcome to TRF! 8)

Edit: And don't forget the oil pan drain plug/bolt washer (you didn't list it, so just being cautious for ya).
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skittishsynapses
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Re: how to locate and replace my oxygen sensor?

Post by skittishsynapses »

Okay, I tried to remove the oxygen sensor, to no avail. I'm doing this from below with the cabby on stands. As far as I can tell, there's no way for me to try this from the top. I have managed a few creaks but otherwise that sucker is stuck good and tight. Tried spraying pb a few times, and while that helped with a couple of the creaks, I have managed little progress. I can't seem to get any leverage to pull down and turn the wretch left. Though I am wondering if I am turning the correct way. Is it left from the top or from the bottom?

I am hoping the PB will help loosen things up by the morning. I've done a few searches and so far the alternatives are warm up the car and spray it in pb, heat the area up with a blowtorch and tap (which I do not have), and use a breaker bar (doesn't appear to be any room, and even if there was, don't have that either).

I've spent a few hours at it and this is looking rather futile. Help?
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Briano1234
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Re: how to locate and replace my oxygen sensor?

Post by Briano1234 »

My trick starts 3 days before.
Spray that sucker with pb blaster every time you think about it.
The day before keep spraying that sucker.
20 minutes before spray that sucker.
Start the car allow to run 2 minutes then shut it off.
Now working your o2 sensor socket on from the top
You use a rachet from the left side as you are looking at it

Lefty, loosy-righty,tighty from the top.
From the bottom it is reversed when you are looking at it.

Another good product is CRC Freeze-off. Spray the crap outta that, wait 20 minutes start the car 2 minutes, then Spray it again (only the o2 sensor keep it off the manifold). Shock the o2 with a wrench and a hammer then use the o2 sensor wrench to remove.

Never had either one fail at all.
Briano

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tolusina
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Re: how to locate and replace my oxygen sensor?

Post by tolusina »

skittishsynapses wrote:........As far as I can tell, there's no way for me to try this from the top. I have managed a few creaks but otherwise that sucker is stuck good and tight. Tried spraying pb a few times, and while that helped with a couple of the creaks,....

Sometimes, when they've been in there way too long, they just will not come out.
For sure I'd recommend an Oxygen Sensor specific socket, several styles should be available at any auto parts store. Top side access is reasonable from the driver's side.

I've been through a week of spraying PB Blaster cold, hot, at the start of a drive, at the end of a drive, all I accomplished was wasting PB Blaster and learning to hate the stench of burning PB Blaster. All that and a variety of serious, professional grade sockets failed to budge it at all.

The solution is an oxygen sensor bung welded into the downpipe, bungs run $5 to $10, a LOCAL (not Mc Chain) muffler shop can hole saw the pipe and weld in the bung in 10 minutes or less.
I've found a decent location on the passenger side, high up and pointing to the passenger side.

---
Bung story.
Bung, there's a word huh? Sounds like something NSFW nasty.
Anyway, I was phoning around locally to shops I do business frequently, most of the guys know me. I'd ask for a bung, I could tell by the tone of their replies they were looking at the phone wondering why I was talking all nashty like that. And no, they didn't have any bungs.
Finally, I called the local muffler shop, decided to ask for an oxygen sensor fitting, the guy replied, "oh, you mean a bung!".
I went and bought his $5 bung, asked him if he'd drill and weld, he waffled, telling me it was possible the VW downpipe was a double wall affair, he declined not wanting to booger things up if it as a double wall.
A1 downpipes are single wall, his concern was well meaning but wrong. Unfortunately, should you run into a similar situation, telling the muffler guy you read on a forum post that the downpipe is single wall isn't going to convince him.
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Re: how to locate and replace my oxygen sensor?

Post by gull »

Here's a trick I sometimes use for those bolts that just seem impossible: I put a box-end wrench on it, or a socket and breaker bar. (I try to use a six-point socket for this when I can.) Then I hammer the wrench in the loosening direction with a mallet. Sort of a poor man's impact wrench. The stiffer the wrench the better it works. I don't usually have to really whale on it, just steady, moderate blows. Often nothing will seem to happen for the first twenty taps or so and then it will suddenly break loose. As a side benefit, this seems to be less likely to shear off bolts than using a long cheater bar, although in the case of an O2 sensor you're not likely to have that problem.
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skittishsynapses
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Re: how to locate and replace my oxygen sensor?

Post by skittishsynapses »

unfortunately for me, 2 weeks after I posted this, I've had no luck getting the oxygen sensor off. sprayed pb blaster liberally day before, 20 minutes before, during, after, etc. I have only succeeded in making my car smoke while driving. I can't seem to break that seal. I've tried giving it a few shocks with a rubber mallet. nothing. Sigh. Not to mention some of the other problems that have arisen lately with my car which I will put in a separate post. I'll take any more suggestions seeing as if I cannot get this off I'll need to have a mechanic proper remove it for me. thanks everyone for all the help so far!
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Briano1234
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Re: how to locate and replace my oxygen sensor?

Post by Briano1234 »

skittishsynapses wrote:unfortunately for me, 2 weeks after I posted this, I've had no luck getting the oxygen sensor off. sprayed pb blaster liberally day before, 20 minutes before, during, after, etc. I have only succeeded in making my car smoke while driving. I can't seem to break that seal. I've tried giving it a few shocks with a rubber mallet. nothing. Sigh. Not to mention some of the other problems that have arisen lately with my car which I will put in a separate post. I'll take any more suggestions seeing as if I cannot get this off I'll need to have a mechanic proper remove it for me. thanks everyone for all the help so far!

No, take it to a mom and pop muffler shop and have them weld a new o2 bung on the down pipe. :) cheaper and they will be done in 30 minutes or less.
Briano

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Re: how to locate and replace my oxygen sensor?

Post by gull »

Yeah, that's a good idea. It doesn't matter that much exactly where in the downpipe it is, especially if you use a heated sensor.
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Re: how to locate and replace my oxygen sensor?

Post by kamzcab86 »

skittishsynapses wrote:unfortunately for me, 2 weeks after I posted this, I've had no luck getting the oxygen sensor off. sprayed pb blaster liberally day before, 20 minutes before, during, after, etc. I have only succeeded in making my car smoke while driving. I can't seem to break that seal. I've tried giving it a few shocks with a rubber mallet. nothing. Sigh. Not to mention some of the other problems that have arisen lately with my car which I will put in a separate post. I'll take any more suggestions seeing as if I cannot get this off I'll need to have a mechanic proper remove it for me. thanks everyone for all the help so far!
This may sound like a stupid thought, but it happens to the best of us at times: Are you turning the wrench in the right direction?

What I usually do when something is stuck: I hit the wrench with a rubber mallet. It breaks the nut, bolt, etc. free 99% of the time. :thumbup:
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skittishsynapses
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Re: how to locate and replace my oxygen sensor?

Post by skittishsynapses »

I've followed someone else's directions from this post about which direction to turn the wretch - lefty loosely-tighty righty from the top, reverse that if working from below. Which I assume would be turn right to loosen, turn left to tighten. Is this correct?

I'm attacking the o2 sensor from below seeing as I can't for the life of me figure out how I would do it from the top. I've removed a black plastic pipe (name escapes me) to try to get at the o2 sensor, but it seems like there isn't a way to do it. If anyone can run through how they get at it from the top, that would be helpful.

Otherwise, I'm stuck getting at this from below. Which is problematic as I can't get a whole lot of leverage or torsion. But it's the option I have atm.

Where would I get an o2 bung from? I've also asked this in another post but, what exactly do I tell a mom and pop muffler place I want done? How much does this generally run?
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Re: how to locate and replace my oxygen sensor?

Post by gull »

Go counter-clockwise to loosen, clockwise to tighten.
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skittishsynapses
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Re: how to locate and replace my oxygen sensor?

Post by skittishsynapses »

clockwise to tighten, counter clockwise to loosen - this applies to working on the car from the top, as well the bottom? I am working from below...
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