Help with O2 sensor removal

**chriskohtc** · 01-23-2010, 10:01 PM

This is kinda an odd place for maintenance issues, but I'll try my luck anyway.

I drive a 2002 Toyota Corolla, and I'm removing the pre-cat O2 sensor.

Here's a picture below.

The oxygen sensor is attached to the diamond-shaped flange below. However, I cannot simply pull it out because the vertical bolt is in the way. I also cannot remove the vertical bolt because the O2 sensor is in the way. Its a chicken and egg problem and I've no idea how to proceed.

I tried tightening the vertical bolt, but it has run out of threads. My only idea remaining is to buy additional nuts, and place it on the top part of the vertical bolt and hope to compress the spring, and hopefully give enough room for the O2 sensor to be removed.

Any ideas? The new O2 sensor comes attached to a new diamond-shaped flange.

Thanks in advance!

EDIT: The vertical bolt cannot be tightened anymore as that is the way it was designed. Its already pressing its maximum against the exhaust manifold due to the bolt shape.

**chriskohtc** · 01-24-2010, 06:13 AM

I have no idea what I did. Placebo or not, I think the cold weather shrunk the bolt enough that I managed to pull the O2 sensor out!!! HURRAAYYY!!!

**languy99** · 01-24-2010, 06:55 AM

I was about to say that another way to do it is the pry between the pipes, because the bottom pipe is held in by the spring pressure it would move enough in a downward position to let you pop it out.

**chriskohtc** · 01-24-2010, 07:10 AM

Originally Posted by languy99

I was about to say that another way to do it is the pry between the pipes, because the bottom pipe is held in by the spring pressure it would move enough in a downward position to let you pop it out.

Yeah, that would be the last option.

I didn't HAVE to replace the O2 sensor, I just WANTED to. To run that risk of damaging the exhaust manifold, or put myself under my car, or breaking anything wasn't worth the gain.

I'm curious, you have a similar car right? Is the pre-cat O2 sensor on your Prizm a flange-type, or the screw-in type? I'm just somewhat disgruntled that Toyota made such a dumb (in my opinion) design choice--where the O2 sensor blocks the exhaust manifold bolt and vice versa.

**languy99** · 01-24-2010, 07:21 AM

it is pre-cat flange type but I don't have spring bolts I have regular bolts and also the flange is nowhere near the bolts. In my opinion the flange type is better then the screw in type because it is much easier to remove after many miles, the screw type rusts in place but it is cheaper to make so most cars are doing that now.

**taylormade** · 01-25-2010, 07:27 PM

Glad you got it. I stripped the threads on one a couple months ago. A simple job got expensive quick.

**chriskohtc** · 01-25-2010, 08:44 PM

Originally Posted by taylormade

Glad you got it. I stripped the threads on one a couple months ago. A simple job got expensive quick.

I know exactly what you mean. Its times like that (when bad stuff happens) when I really wonder why I spent all this time trying to save money, only to end up costing more money.

On a separate note, whenever you install a new O2 sensor, expect to have white smoke and a burning smell when the engine is first started. I totally did NOT expect that and thought I had an extreme exhaust leak which instantly made me regret my actions....