: Need Advice: Replacing Rear Bank O2 Sensor 97 Deville



jimbo49
11-20-04, 12:28 PM
For a 97 Deville:

I am getting a P0135 code, therefore I plan to replace the rear bank O2 sensor at the exhaust manfold. I have the GM service manual for this model/year.

It says that I need to support and the lower the rear portion of the Engine Frame 3 inches. Frankly, this scares me.
I have the following tools:

1 hydraulic floor jack
1 hydraulic bottle jack
4 jack stands

Question 1: Is there any way to replace this sensor WITHOUT lowering the rear part of the engine frame 3 inches?

Question 2: Will someone who has lowered the rear part of the engine frame a time or 2 please post your recommended procedure as well as "watch out for this" or "be prepared to do this" advice?

The GM manual says that there may be junk in the cage bolt threads in the body. They therefore say that a tap may be required to clean out the threads to allow reinstalling the frame bolts. Should I be ready to buy a tap set?

:confused:

Pjs
11-27-04, 10:54 AM
The main thing you need to watch for when lowering the back of the cradle is where the steering knuckle from the columm attaches to the rack. You can drop it a good ways before it exerts pressure on the rack and columm but it's something that you need to keep an eye on. Pry up the rubber boot from the steering rack and take out the bolt if you want to sure, just in case your jack slips. As far as the cage bolts go, I've had mine in and out a couple times, no problems except that I crosstreaded one going back in (even starting it by hand). Cad dealers do NOT have those cage nuts listed in their catalogs. In order to replace mine I'm going to have to have a friend weld me a nut to a new washer and feed it into to hole..not a fun time I can tell you

Pjs
11-27-04, 11:01 AM
You may want to look and see if you can't get to it by removing the coil pack and going over the top. I haven't replaced mine that way but in sizing it up I swear there is enough room (95 SLS), however I could be wrong but it won't hurt to check it first.
Lowering the cradle is pretty straight forward and relatively easy. The main thing you need to watch for when lowering the back of the cradle is where the steering knuckle from the columm attaches to the rack. You can drop it a good ways before it exerts pressure on the rack and columm but it's something that you need to keep an eye on. Pry up the rubber boot from the steering rack and take out the bolt if you want to sure, just in case your jack slips. As far as the cage bolts go, I've had mine in and out a couple times, no problems except that I crosstreaded one going back in (even starting it by hand). GM dealers do NOT have those cage nuts listed in their catalogs. In order to replace mine I'm going to have to have a friend weld me a nut to a new washer and feed it into to hole..not a fun time I can tell you.

nitrous1
11-28-04, 03:55 PM
I'm not familiar with the engine bay on a Deville, but I recently changed the rear bank O2 sensor on my 96 Seville. I was able to get to the sensor with a long extension and a 7/8" crowsfoot adapter. This may not work for a Deville, but it might be worth looking into.

Good Luck,

nitrous1

mcowden
11-28-04, 07:43 PM
On my '96 SLS, I was able to remove and replace the B1S1 O2 sensor with only a long 1/2" extension, O2 sensor socket, and 1/2" breaker bar. It wasn't exactly convenient access, especially fishing the new sensor down to the manifold and getting the threads started by twisting the harness gently, but I got it done. Maybe on the DeVille there is less clearance between the engine and firewall, or the O2 sensor is at a funny angle from the space between them so that it wouldn't be easily reachable, but definitely take a look. Maybe it could be done with a u-joint or a swivel extension. For a DIYer, lowering the engine seems like a big PITA. If you can at least get the front end of the car in the air, it might be easier to start the threads from below instead of what I did. (wish I had a video of the entire process for laughs) Unless you can't even see it from above, I think it can be done from there. Maybe one of those ratcheting crescent wrenches would make it possible from below without dropping the cradle?

If you can take a picture from above looking down at the sensor, post it here and I'll bet you get a bunch of suggestions on how to get it done.

Good luck...

Michael :cheers: