Well that was fun...

While I found some videos on the procedure, none from Atlantic British actually did the work. Just a walk-through. I knew going in that the driver side would be hell and it sure was. I think in total it took me about 5 hours with the vast majority of time wasted on figuring out how to do it. Like most things, the next time will go much quicker. The passenger side, 30 minutes tops. The best part? I think they may have been replaced already. I can not be certain unless I can find a date code on the Denso sensors. But they looked to be in excellent shape. Much like the excellent looking spark plugs I replaced that certainly were factory - worn, but very clean.s

So some tips that may help those in the future.

Remove the trans shield. Gives you just a little more needed room.

Unbolt the front drive shaft at the transfer case (rear end of shaft). Just do it and save the time I wasted. There is just no easy way to get that connector apart unless you hav tiny little hands. There are six TORX bolts to remove. So you will want a proper 10mm torx socket. Rover likes to use these so you may as well spend the $15 and get a set from Harbor Freight. They are in pairs with a small metal bracket. Someone correct me, but I dont think you have to mark the position. I did but in the end when free, driveline tension spun things out of sync anyway. Once you have the bolt out you need to free the shaft. Get a good sized hammer and something to help hammer on the shaft base. There is a grease cap, try all you can to not pop it off. And if it rotates, have fun getting it lined up again and not getting black grease all over the place. But the drive shaft is bonded a bit to the input shaft. A few good sold whacks should break it free. Once free you can compress the shaft little. Then you may find that the O2 sensor bracket for the downstream is in the way. I bent mine to give the shaft as much room to move around as possible. Going forward you may be moving that shaft side to side as you find the best way to get to the sensor.

The connector is a squeeze type. You press down in the aft portion of the connector at the main harness side. The tricky part is to pull on the O2 sensor wire at the same time to pull the plug out. No way to get two hands up there. So take a few cables ties, or whatever, and secure them to the O2 sensor wires. Now with one hand pressing on the plug use your other to pull down and separate the connector.

With any luck the sensors will not be hard to remove. For some odd reason shops love to crank them down. First, that can break the ceramic inside. Second, its just not needed. Treat these like spark plugs. Use a breaker or such with an O2 sensor tool and find your method to break the initial bond. Once done, they should come out easily. I actually went up into the engine bay, knees on hood lip/fender and reached down behind the engine/under the cowl with a short ratchet and deep O2 tool. Once your elbow is under the cowl there is actually a lot of working room. You *may* be able to use a deep O2 socket, u-joint and extensions and break the bond/loosen the sensor completely from top. But I dont think you can really get to the connector. With my shorty I did just a couple turns then the rest by hand. And since you are up there, install the new sensor. I can not imagine installing it from below. But from up top, its really easy to thread it it in. I used my shorty to tighten it up before going below with the breaker for a final snug.

Now you just need to get the shaft back together, install the trans shield and bend the downstream bracket back. The passenger side, no tricks. Easy as can be.

 

Hi guys here goes my second attempt I have a 2005 LR3 v8 and some how while offroading the o2 sensor left side downstream plug got ripped of now I don't know what wire goes where is there anyone that might have had the same problem or might have any info on thisany help would be greatly appreciated

 

Next on my list - sounds dreadful. Thanks for posting.

 

I understand that my question is probably a dumb one, but I am a reasonably new owner (about 6 months) of a 2007 LR3 and I follow all you more experienced guys daily...How do you know when you need to replace an oxygen sensor?

 

You can get codes but generally I go by milage. I prefer not to run upstream plugs more than 60,000 miles. Downstream, double that usually. Upstream have a direct impact on fuel economy, downstream pretty much just make sure the cats are working and being post-cat they hold up longer.

 

Thanks.

 

Is that part of any factory recommend maintenance interval?

 

Not with the LR3, there is nothing listed for O2 replacement at all. I go by the widely accepted interval of 60k for all my vehicles, some say 100k for newer vehicles. And with mine, purchased at 105k miles, replaced them for good measure. Its not like they are terribly expensive - which is why I also go 60k not 100k miles.

 

....what's the shop time?

 

@houm_wa I figure that is directed at me?