Shall one replace o2 sensors?

[dashhho]

my '05 B4000 has 140k miles on it. It runs okay, alot better now that I put in motorcraft plugs and wires as the previous owner used NGK!!

How do the ranger gurus feel on o2 sensor replacements. Do they need to be done if no codes are thrown? Is it really preventative maintenance or will they last a long time? Will I be mashing my knucles for nothing

My old dog has ~140k miles on it. Is it worth replacing them? I do intend to keep the vehicle for a long time but I was thinking of a 5.0L v8 swap sometime possibly...

 

[RonD]

100k miles or 12 years which ever comes first

O2 sensors use a chemical reaction to detect Oxygen in the exhaust, over time, and use, the coating gets used up and they start to show "false lean" so computer runs engine richer and richer without knowing any better, until you start to get Lean Codes
So by the time you get a code you could have replaced O2 sensor 3 times over in fuel savings by doing it earlier

O2 sensors are the only sensors that can actually wear out

 

[dashhho]

100k miles or 12 years which ever comes first

O2 sensors use a chemical reaction to detect Oxygen in the exhaust, over time, and use, the coating gets used up and they start to show "false lean" so computer runs engine richer and richer without knowing any better, until you start to get Lean Codes
So by the time you get a code you could have replaced O2 sensor 3 times over in fuel savings by doing it earlier

O2 sensors are the only sensors that can actually wear out

Wish I knew this before I put my wheel well plastic back in! Think I can still get at the upstream ones tho, just will be tight.

Rockauto only sells motorcraft upper sensors, any recommended brand for the downstream?

 

[DILLARD000]

My 2001 ExST V6~4.0L~SOHC with single exhaust has 3 OxygenSensors as shown below;
not sure if your 2005 B4000 V6~4.0L~SOHC has single\dual exhaust & 3\4 Sensors?
Left upstream & rear Sensors are easily gotten at from below;
right upstream is more inconvenient thru the fender skirt with the 4wirePlug between engine+firewall.
I'd just go with Bosch. More info & list of makers at
https://2001fordexplorersporttrac.fandom.com/Engine_Exhaust_OxygenSensors

 

[RonD]

The difference in Ranger O2 sensors is the length of the Lead wires that come attached to them
i.e. 6", 10", 1ft ect..............

They are the same internally and have Ford O2 connectors attached, so you can use any Ranger O2 sensor in any position as long as the wires are long enough to reach the truck's harness connector

The rear O2 often plugs into driver's side transmission harness, so wires go over the top of the transmission to passenger side

 

[Dirtman]

If yours is anything like mine just buy the rear ones even for the front. The one for the front of my truck came with a wire about 3 inches too short so I ended up buying a downstream sensor just to have enough wire to plug it in properly. Cheap bastards at Bosch...

 

[19Walt93]

Try looking up cat monitors instead of downstream O2's. That's what Ford calls them.

 

[Roert42]

I believe the length of the rear sensor wiring is also dependent on the transmission type.

I think the winning for the manual trans is longer then the auto, but it could be the other way around.