Looking for Tips for O2 Sensor Removal
 

I'm trying to replace the O2 sensor on my '87. :mad:

Half hour job my butt.

I was able to grind off all the bolts that hold the heat shield on, so it's just me against this sensor. With a 22 mm open end wrench, this thing doesn't budge. I can actually feel the wrench flexing.

I sprayed some PB blaster on there last night and will probably give it a few more shots again before trying again.

I don't have access to a torch. What other tips can anyone offer me?

Should I drive the car first to heat up the manifold?

Would I be better off using an O2 sensor socket like this one from HF along with a breaker bar? Or will that just flex the socket and end up stripping the points on the sensor?

I don't want to cut the wires if I don't have to, because I'm afraid even if I do I still won't be able to get the darn thing off, and then I can't drive the car. Drilling seems out of the question...

Any advice you can offer me is appreciated.

Matt

Cut the wire and get a closed wrench or full socket on it with a breaker bar. You will need to replace the sensor but the best is to cut the wire.

PB Blast it and also try removing it when hot after letting motor warm up. You may even need to heat the bung that the sensor is threaded into with a torch.

The sockets for removing these sensors don't work well if the sensor is that tight. I have these tools and they simply will slip at more than 100 foot lbs.

Matt,

Sorry, but my experience is that if it is stuck, heat is the only answer. A minute and a half with a $15 propane torch will usually do it. You need one.

+1

Yep. Heat, and an impact hammer, is what it took. And the threads were pretty buggered up...

Bo

You don't need to cut the wire. Unplug the wire inside the engine bay, push the rubber grommet out of the engine sheetmetal. Then you can slip the pigtail connector and grommet thru the closed end wrench. Shock is your friend here because you need to break the rusty bond. Hammer on the free end of your wrench with a heavy hammer.

I had this same idea, Kevin. I think this weekend I'll have some time to revisit. PB Blaster + shock hopefully = :). If not, then I'll have to get a torch and try some heat, too.

Thanks for the ideas. I'll report back what happens.

BTW, your car will run pretty well with the O2 sensor disconnected, so don't let that get in the way of your efforts to remove the sensor.

The Cap'n

Are you trying to save the sensor? If not, cut the wires or get a special O2 socket.

Success!!!!

Got it out. However, the threads in the manifold bung are pretty knackered up. What thread size is the sensor, anyone know? Gonna need to chase them or retap them...

M18x1.5. Old Fords used this thread for spark plugs, so thread chasers are pretty available. Here's a tool number from Google: Lisle LIS12230 Oxygen Sensor Thread Chaser. I'm guessing you'll find it at your FLAPS, but it might be WAY cheaper online.

The Cap'n

+1 - You will find it at O'Riellys or NAPA. Auto zone / Advance Auto, doubt it.

FWIW, Called Advance Auto for an 8MM triple square bit. Response was, "Huh"?

NAPA had it in stock.

Thanks, guys! Found it at O'Reilly and got the job done.

Tip for anyone in the future who uses one of these things: don't use the 3/8" drive. Rather, use a 3/4" socket. It distributes the load better. I broke mine using the 3/8" drive.

So, what did I learn/how did I do it?

1. I brought the car up to operating temperature first.

2. I used a pick and small screwdriver and scraped under the actual sensor where the crush washer meets the manifold to remove as much rust as possible. Then I took a small screwdriver, put it under the sensor against the crush washer, and smacked it a few dozen times with a hammer to hopefully loosen the rust.

3. I then sprayed some PB Blaster, let it sit for about 20 mins.

4. I didn't cut the wire. Per Kevin's suggestion above, I disconnected the sensor, pushed the grommet out of the sheetmetal, and fed the dongle and grommet through a 22mm box end wrench. Then I reefed the piss out of it.

5. I bought an M18 x 1.5 thread chaser from O'Reilly Auto parts and, using some cutting oil, chased the threads, which were pretty beat up. If/when I do it again, I'll use a 3/4" socket with the chaser, rather than a 3/8" drive.

Sweet.

For the future, in these types of situations, I like to use Mapp gas and a standard propane torch.

If I have a "special" POS, MF'ing, PITA fastener I have the Bernz-o-matic Oxy/Mapp(Propane) torch setup. It will turn everything a nice dull red but it will not pull off a cherry glowing red like oxy/acetylene.

Bummer is the red oxy tanks run out after about two jobs.

BERNZOMATIC Welding and Brazing Torch Kit - G4720204 at Zoro

Well said! :D

Some general techniques for dealing with rusted fasteners in an exhaust system:

- PB Blaster or other penetrating oil (not WD40) multiple times over a week leading up to the job.
- If fastener is in good shape (points not rotted away) and it won't come out just use a MAPP torch straight off (assuming you won't destroy anything nearby that you need).
- Use a *good* 6 pointed socket or box wrench. Snapon, for example, has sides that are slightly convex so grab the flats on a bolt well. For an O2 sensor, get the special socket.

The heat is key IMO. For something like an old O2 sensor that I didn't care about, if I knew it were frozen, I'd be temped to cut the top off so a socket would fit over it, heat it so it's glowing and then odds are it'll come out. Put anti seize on the new one.

O2
 

Since we are in this topic...how does one know that an O2 sensor is bad? What symptoms will be evident? I have an 89 Targa.

Good question. In general terms, if you're getting bad gas mileage and/or the engine is low on power, simply replacing the sensor isn't a bad idea. Also, I had the bouncing idle problem and replacing the O2 sensor on mine helped but didn't cure it.

Here's a good test otherwise.

https://www.youtube.com/watch?v=QM2jO0_Cah0

How do you know the O2 sensor is bad? In my case on my 87 Targa 3.2 I had a nasty case of the "herky jerkies" when it was cold in lower gears. As it warmed it became less jerky at low RPM. I suffered with it for a couple years, pulled the connecting wire, it got way better. I couldn't get the O2 sensor out (but have a nice 22mm open end wrench in the tool box now!) so I took it to my servicing place who managed to get it out and installed the new O2 sensor. It's been fine ever since.

this made me laugh. I can't tell you how many "easy" "30 minute jobs" took me forever because of one damn stuck bolt or something. Cars would be easy to work on if not for unexpected hangups. Instead I end up swearing and occasionally throwing things. I find nothing beats shear rage for dislodging something.

My DIY rule is if someone says it will take X amount of time... they are lying so triple it. Double the DIY cost. It is like asking a woman how many men she slept with in her life; she will lie and minimize the number. Same for men reporting diy times/cost on an internet forum.