Confused on O2 Sensor Replacement

[DeathCruiser]

Hi Everyone,

Just a bit confused. I finally got a new set of O2 sensors for my rig. I figured they would help with gas mileage and overally performance. When I got under my truck tonight I couldn't figure out exactly how they are attached. I see that there are two bolt studs protruding through the sensor mounting flange, but there were no nuts on either of the studs on either sensor. I'm guessing someone was messing around with the sensors in the past and never put the nuts back on. In any case the only thing that appears to be fastening the sensors is rust build-up where the stud meets the flange. Any guesses on this one? Any suggestions. Am I missing something? I figure that I need to clean the rust from the threads and buy some new nuts to put on with the new sensors. Just seemed extremely odd to me that there appears to be nothing holding on the sensors.

I would appreciate any HELP or COMMENTS.

-Andrew

 

[Koffer]

Well your rust buildup is whats left of the nuts
I just used a small cold chisel to more or less crack whats left off and installed the new O2s
One of mine blew out of the hole while driving as the nuts rotted all the way off but the studs were fine

 

[DeathCruiser]

Well your rust buildup is whats left of the nuts
I just used a small cold chisel to more or less crack whats left off and installed the new O2s
One of mine blew out of the hole while driving as the nuts rotted all the way off but the studs were fine

That's crazy! Thanks for the reply. I'll have to go to a hardware store and get some new nuts, but at least I know what happened to the old ones. That heat must really speed up oxidation. How did your truck run after the swap?

 

[Koffer]

That's crazy! Thanks for the reply. I'll have to go to a hardware store and get some new nuts, but at least I know what happened to the old ones. That heat must really speed up oxidation. How did your truck run after the swap?

It ran like I added almost 100hp ( I added a SC and full blown tuneup at the same time I changed the O2s )

:whoops:

 

[Skillet]

mine were rotted as well. I used some of those damaged nut remover things I bought from sears. Very tight area to work in and they worked well.

 

[L8Shift]

I believe the nuts are metric "8mm x 1.25" thread, I used flanged, stainless, serrated nuts...

Sensor cover p/n 89437-60030 in case you need that too.

It appears to accelerate a tad bit quicker ... no mpg #'s yet..

 

[landtank]

I just did my front one a few weeks back. The nuts were almost totally gone. Be sure to run a die down the stud before using new nuts.

 

[DeathCruiser]

Thanks for all of the replies. I did replace the sensors and put new nuts on. Two of the nuts had completely rusted away. Unfortunately, after getting the two remaining withered nuts off I discoverd that the bolt studs under them were pretty well corroded too. One of them I was able to salvage by breaking the stud just below the rusted area, leaving enough room to put a nut on. The other, however, could only be broken off too low to put a nut back on. So, one of the O2 sensors is missing a nut. Both are held on pretty tight, but I hate the idea of the system being messed up.

I think that my exhaust system is almost shot the way it is. It is basically hanging by the manifold, because the factory welded mounts broke about 10,000 ago. I put a set of aftermarket mounts (the kind that clamp on to the exhaust pipe and can be hung from the frame) to replace the factory ones, but the high heat weakened the rubber in the hangars in no time. My exhaust is now hanging from the manifold and resting on one of the frame's cross bars (creates the most annoying vibrating noises during low RPM idling). I think it is time for a new exhaust.

Any suggestions on this situation? Where would be the best place to look into getting a replacement exhaust? I certainly don't want anything much different than the factory put on. Do I need to go to Toyota for a new system? Is it unusual for these exhausts to break after 10 years, 155,000 miles?

Thanks again!

-Andrew

 

[GXO]

You are lucky you made it this far if you are in the salt belt.

There are a LOT of write ups about aftermarket systems. The mounts for the 02s are a bit custom so I am unsure I know how that would work.

I know I have seen posts about this...may want to search a bit.

 

[MTBGUY]

IMO, the stock Toyota exhaust has lasted longer on my LandCruiser than any of my previous cars. The factory exhaust would be pretty expensive, I think, to replace but maybe Cdan can get you a deal.

You can have an aftermarket exhaust welded on fairly inexpensively at a local shop. But just make sure you do some research on who the good local ones are- I've had good luck with independent specialty shops in the past- but have had ALL SORTS of stuff screwed up by the large chain/franchise stores you see all over the US. On the last (and final) trip to a Meineke muffler they left my O2 sensor loose in the exhaust (not bolted in) and it was hanging on by the wires when I drove in my driveway!

They can weld your old Toyota O2 "bung plates" onto the non-factory exhaust so it wont be a problem to worry about.

Im up by about 2 MPG after getting new O2s.

 

[L8Shift]

...Is it unusual for these exhausts to break after 10 years, 155,000 miles?
Thanks again!
-Andrew

In my case, @151k the exhaust itself was still fine, no holes, and no codes for the sensors...just ALL the Hangers were totally shot, weakest link....it's the longest I've had an original exhaust too. I replaced the exhaust just to be done with it and the sensors in search of better mpg too(TBD) ...

 

[Nay]

I just did my O2's. My fuel level gauge is messed up so it shows empty at about 16 gallons (the low fuel light still works properly, though), and I used to get about 185-190 on 16 gallons and I just got 215 today. Truck is running a LOT smoother.

Nay

 

[Bat Masterson]

Stud Length

Do you need an extended socket for the studs or will a standard one work?

I just received 2 new 02 sensors from CDan with 4 new nuts and sprayed the studs with PB Blaster for this weekend's tuneup project.

Mine looked pretty rusty as well and just don't remember how long they were...

Dave

 

[OGBeno]

The nuts are 12mm...but mine were so rusted and the like that I ended up using the box end of a 11mm wrench and, as you said, blasted it with PB to get them going.

Once they were off, I cleaned the threads of the studs and was able to hand tighten to the nuts and then used a small 3/8" 12mm socket on a ratchet.

No extension. My hands easily fit up in there,

While you are in there, make sure that you check the wiring on the female end of the connectors. I ended up splicing sensor 1 and am still getting a CEL/MIL after the new ones (P0125) which is either due to the sensor splicing or the sensor at the block.

Best.
-o-

 

[Bat Masterson]

Thanks for the information. I'll hit it in the morning and hope those nuts come off easy. I have factory sensors so hopefully it's just a simple plug and play.

Dave

 

[Cruiser804]

Where are all you NOVA cruisers. Are any of you members of CLCC? I am in Herndon.

 

[RavenTai]

Is it unusual for these exhausts to break after 10 years, 155,000 miles?

10 years and 168K or so here and my exhaust is just fine, I was under there yesterday and took a look at the O2 sensors expecting to find Rusted nuts, just a little surface rust in spots on mine, exhaust is good shape also except for some cracking in the rubber on the hangers, I will probably be forced to do something about those at around 200K.

I think exhaust life is very dependant on salt exposure, my 80 has never seen salt,

 

[Bat Masterson]

NOVA

I'm in The Plains and work in Oakton and D.C.

Not a member of the local clubs as I'm a recent LC owner and in the process of fixin' er' up. Mostly on road/commuter vehicle but admire all of those rock crawlers out there. Also just like the fact that I can do some mild 4 wheeling in the Blue Ridge/Piedmont area of VA and just be satisfied that my new vehicle will be able to handle it. There are many unpaved roads out here in Western VA and it helps to have the LC in certain spots.

Dave

 

[Bat Masterson]

Just added my Avatar--cousin of Bat Masterson so thought it would fit.

 

[Bat Masterson]

Bought Bolt Out kit tonight and blasted with PB Blaster again. Tried to use an 11 and 12mm socket and neither worked due to serious rust deformation. I will use Bolt Out tommorow during day time. Saturday is big tune up day.

Also bought thermostat and fuel filter and may elect to postpone those due to excessive labor required. I have a Toy master mechanic that I know so may take it in for him to do. I'll look at the fuel filter anyway to see how difficult it is. I have read up on many posts regarding that issue. Finally--#6 spark plug replacement will be a plug and pray situation. I will definitely take my time on that one.

Dave