02 sensor: plenum removal 100% necessary? ATTN: Q451990

[masshead87]

I know I've roughly asked this question already but since my last post on it got sort of convoluted and felll by the wayside, I'm trying again.

Is it absolutely necessary to take the plenum off to change the O2 sensors in my 96 Q? There's an article on Q45.org saying he got two off without needing to, and referenced Q451990 who said he got all four off without needing to. But there are no pictures, and the article is actually fairly discouraging, a rare miss for that site...
A link that that post by q451990 would be mighty fine.

I may not be keeping this car much longer. It still runs fine but we're headed to $4/gal again and I just can't see myself paying 0.30 and up a mile to drive a car that I already own outright. So with that in mind, if I can just change the sensors to get the MIL to shut off, I'd really rather do that than put another $12-1500 in maintenance into a car that I'll likely just be selling or trading in before the end of the year.

[maxnix]

Then why worry?

You might so the math and figure how much you "save" by buying a new car that gets better gas mileage.

If you find $1,500 per annum cost of maintenance daunting for an imported V8 luxury car, you own the wrong car.

Plenum does not need to be removed for O2 sensors. They are in front and behind each converter.

[masshead87]

Then why worry?

You might so the math and figure how much you "save" by buying a new car that gets better gas mileage.

If you find $1,500 per annum cost of maintenance daunting for an imported V8 luxury car, you own the wrong car.

Plenum does not need to be removed for O2 sensors. They are in front and behind each converter.

I worry, since I haven't totally made up my mind yet. And I've already put roughly $2k into the car so far. And I really love it. You're right, in the short term I won't be saving by buying something new and more efficient. 33k for a new Taurus? No thanks.

Maintenance costs are not what's bothering me, although frankly my Mom's BMW was markedly cheaper to maintain than this. It's projected running costs that are daunting, when the bigwigs say we'll be paying $5 a gal for prison-grade 87 octane before too long.

I was just worried that I would have to take the plenum off, and if that were the case I might as well do the whole set of BS that's underneath it. Seeing as how that doesn't have to happen every year, I figure the work would be well worth it, unless of course I couldn't afford to put gas in the thing to move it!

Thanks for your input. I'd still like to find Q451990's post on his experience switching them. I've been searching for an hour.

[Q451990]

I have replaced them on both cars using a method that's probably not the best - but met what I have on hand for tools. I have been able to snake a couple of extensions with an O2 sensor socket (the kind with a notch on one side to accomodate the wire) between the firewall and engine and get to them that way. I'm pretty sure one extension had a wobble head. The second time I did this (on my current Q) the sensor was seized in a bushing that screws in to the header, and stripped it out, so I had some extra work replacing that spacer.

The FSM recommended way is to use a crow's foot style wrench - but I have never done it that way. The rears are non existant on the earlier Q, but should be very easy. I wouldn't replace them unless they're throwing a code... rear sensors are more of a check, and don't do any actual engine control. www.sparkplugs.com is a good source for the sensors. The NTK "OEM equivalent" live up to their name...

I would recommend putting some liquid wrench/wd-40/etc. on them a day before you start. That should make your life a little easier.

Good luck!

Heath

[maxnix]

PB Blaster 24 hrs. ahead of loosening.

The crow's foot wrench does help, as does a lift.

[elwesso]

Ive replaced o2 sensors a couple times, I'm not sure what kind of o2 sensor socket you guys are using but I could never even get an extension to engage on the passenger side...

The article on Q45.org is pretty scant because theres not much to it... Maybe 3 hours first time you do it, then 1.5 every time after.. It really helps to have a helper, even if its just your kid or your wife to hold the extensions from the top while you fish it out from the bottom. Once they break free they're pretty easy to get out.



The drivers side o2 sensor is angled toward the middle of the car, so I use a series of extensions with an o2 sensor socket so that I am actually loosening it somewhere behind the middle of the plenum, on the top.. Its kinda tricky but you'll figure it out.. I do the passenger side with a 7/8" crows foot socket (i bought a whole set from the hardware store for like $15).. I think last time I did it I did it from the bottom, but I cant remember for sure..

[OwnerCS]

I must admit - I dreaded changing O2 sensors like it was a root canal..

Almost by accident, I purchased two types of O2 sensor tools from Harbor Freight. I figured one or the other tool types would work. As it turned out one was better for the left side than the other.

On the left (drivers side) I used this one:

http://www.harborfreight.com/3-8-eighth ... 95045.html



On the right (passenger side) this one worked better.

http://www.harborfreight.com/3-8-eighth ... 97177.html



So for less than $14, I bought the tools I needed.



I've got some pictures of these tools in action that I will add to my photobucket and post in a few here today.

After it was over, I felt kind of stupid about procrastinating about doing it for so long..

But my 91 model only has two O2 sensors and I can't speak for how involved it may be to change the other two on a 96.

[OwnerCS]

Some pictures from the O2 sensor job..

Note: I crawled up into the engine compartment and stretched out over the engine to take these pictures. I used a couple of layers poly foam as padding so I could stretch out over the engine and radiator fan shroud. The need to crawl into the engine compartment will depend on your physical size, along with arm and leg length. Personally I found it easier than trying to reach across the fenders and engine – but it just depends on your preference. Also, I had many components already removed from the engine that facilitated the O2 sensor pictures. Experiences from other members can help determine your final approach.

Helpful tools.



New O2 sensors. Other members have sources for the best deal.



The driver side (left) O2 sensor.



Using the longer O2 sensor tool on the driver side.



Positioning the extension along the firewall and bell housing to loosen the driver side O2 sensor.



An unsuccessful attempt to remove the passenger (right) side O2 sensor with a straight extension.



A look at the passenger side O2 sensor with universal joint extension and angled removal tool.



Running the passenger side (right) socket extensions along the firewall and down to the universal joint and and tool in the previous picture.

[masshead87]

COOOOOOOOOOOOL , thanks a ton you guys!

You've helped me, and every other marginally mechanically inclined person who will attempt this job in the future!

[masshead87]

OK, well now that I'm done digging myself out for the whatever time this month, I've finally got to strap it down and replace this thing. I'm going to be making a longer commute coming up shortly, so no more putting it off.

It's P0136: Bank 1 sensor 2.
So that's the driver's side post cat, right?

NGK OE identical O2 sensor 24681 24681 After Catalyst Left $95.85
is what sparkplugs.com is giving me.

Just want to confirm this is what I need before I click checkout. Also going to be getting a new airfilter to put in at the same time.

[OwnerCS]

I just went to that web site and followed the menu selections for my year model and the rest went according to plan..

Our member named Qship96 is our resident expert on sensors and plugs for the 96 model..

Qship are you online today?

[maxnix]

Sparkplugs.com has in the past not listed the correct sensor on their website.

Always best to call.

Bank 1, Sensor 2 is DS. Best to replace in pairs for similar duty cycling. Less critical on the post converter sensors.