Which vendor has the best O2 sensors? It seems that I keep reading about someone buying their sensors from one vendor only to have them go out 3 months later so they buy them from another vendor and they work great. I'm going to need to replace mine soon and just looking to do it once, not over and over in the same year. I searched, but there's too much muck to filter through with everyone's code problems.

 

"I have repurchased the supposedly correct O2 sensors from the British Parts of Utah ...I don't understand how AB can be selling O2 sensors that won't work on my model Disco 2."
I cut this from a recent post of a fellow who was having a lot of problems with 02 sensors.

 

I purchased Bosch O2 Sensors, didn't have any issues. Purchased from a local O'Reilly's who will warranty them in store if I have any issues. You may pay a little more for them locally but the hassle of warranty is worth if for me.

Inspect all the wiring before hand.
Make sure your fuel injectors are clean and functioning properly.
Make sure there are no cracks anywhere in the y-pipe (the exhaust pipe where the O2 sensors are located). Mine cracked at the weld at the exhaust flange.
Make sure no exhaust leak on the exhaust manifold.
Check for vacuum leaks or replace all vacuum hoses.
Finally Torque to RAVE specs - 33lbs. Use anti-seize on the threads. I actually also spray some electrical contact cleaner in each end of the pigtails as well.

Per RAVE:
The HO2S can fail the following ways or supply incorrect signal:
l Sensor open circuit.
l Short circuit to vehicle supply.
l Short circuit to vehicle earth.
l Sensor disconnected.
l Stoichiometric ratio outside the correct operating band.
l Contamination from leaded fuel.
l Air leak into the exhaust system.
l Wiring loom damage.
l Sensors fitted incorrectly or cross wired.
In the event of a HO2S signal failure any of the following symptoms may be observed:
l Default to open loop fuelling on defective bank.
l If the sensors are crossed over (LH bank to RH bank), the engine will run normally after initial start up, but
performance will become progressively worse as the sensors go towards maximum rich for one bank of cylinders
and maximum lean for the other. The ECM will eventually default into open loop fuelling.
l High CO reading.
l Excess emissions.
l Strong hydrogen sulphide (H2S) smell until the ECM defaults to open loop fuelling. .
l MIL illuminated (NAS market only).

 

I bought the Bosch sensors from Advanceautoparts.com when they had a "buy X dollars worth of parts and get Y dollars off" sale. Total cost came out to be $220 - $55 each. One set is more expensive than the other, can't remember which.

I did have an issue where the right rear connector was inaccessible to me. I had wondered why they sold other Bosch sensors with a connector kit as also being "original replacement." Now I know why - wires may have to be cut and another connector installed in line. Sent the original new one back and awaiting delivery of replacement.

Since I replaced the three, the intermittent warning light and O2 related codes are gone and haven't recurred. About 600 miles since replacing.

I guess it depends how strapped you are for cash and how much you intend to shop around. Seems like there's a lot of debate about who makes OEM sensors and which you should buy. I went with Bosch since I know the name and consider them to make quality products. With any luck I'm done with O2 sensors for another 80k miles or so.

DRW