Oxygen / lambda sensors

Count the wires. One or two wires (unheated, 1980s) is near-worthless; four wires is the 75-cent baseline; five or six wires with an OEM Denso, Bosch or NTK part number is a $20–40 used part, not scrap.

Pt 13 mg per sensor (≈0.05 g/lb)Cu 8–20 g in the leadBase steel body

eBay typical$2–5per lb

Refiner pays$1.8per lb

Metal in it$3.30per lb at 4 Aug 2026 spot

Confidencemedof the yield figures

How to spot it

Steel hex body about 22 mm across the flats, M18×1.5 thread, 3–5 inches long, with a ceramic-and-wire tail exiting a boot. Upstream ones sit on the manifold or downpipe, downstream after the converter. Stamped Bosch, NTK/NGK, Denso or Delphi with a part number. 60–150 g each, 2–8 per modern vehicle.

Metal content

Metal	Quantity	Notes
Platinum	13 mg per sensor (≈0.05 g/lb)	electrode + heater track; wideband may reach 25–60 mg — estimate only
Copper	8–20 g in the lead
Base metal	steel body, zirconia element

At 4 Aug 2026 spot prices that works out to $3.30 per pound of contained metal — Platinum 0.052 g = $2.87, Copper 40 g = $0.43. A refiner paying $1.8 returns about 55% of that, which is normal: refining costs money and the buyer takes a margin.

Safe removal

Working temperature: Cold engine only

Engine stone cold. Exhaust hits 800 °C and the threads gall. Use a slotted 22 mm O2 socket or an offset wrench, with penetrating oil and a heat cycle. Cut the connector at the harness only if you're scrapping; unplug at the connector if you're selling. Never pull on the wire — it snaps the internal platinum leads.

Hazards

🔥 Thermal burns

Don't rush a hot engine. Nothing here is worth a hand.

☠ Hydrogen fluoride from fluoropolymers & lithium

NEVER torch, incinerate or overheat PTFE insulation, and never smoke around PTFE dust — it converts on the cigarette.

🧪 Automotive & battery fluids

NEVER pour any of these down a drain or onto the ground. They are all regulated waste streams.

Before you scrap it

A tested-working Denso or Bosch wideband AFR sensor is $20–40 used against 75 cents as scrap — 25–50×. Narrowband is about 13×. Sell the sensor, not the platinum.

The common trap

The arithmetic kills the hype. Refiners pay about $3/lb and roughly four sensors make a pound — 75 cents a sensor. At 13 mg that's 72 cents of contained platinum, a near-perfect match. The widely repeated "0.1–0.2 g of platinum per sensor" would be $8 of metal; no refiner would buy that at $3/lb. It's wrong by about 10×. There is also no palladium and little or no rhodium in them.

Questions

How much gold is in oxygen / lambda sensors?

Platinum: 13 mg per sensor (≈0.05 g/lb). Copper: 8–20 g in the lead. At current spot that is about $3.30 of contained metal per pound.

How do you identify oxygen / lambda sensors?

Count the wires. One or two wires (unheated, 1980s) is near-worthless; four wires is the 75-cent baseline; five or six wires with an OEM Denso, Bosch or NTK part number is a $20–40 used part, not scrap.

How do you remove oxygen / lambda sensors safely?

Engine stone cold. Exhaust hits 800 °C and the threads gall. Use a slotted 22 mm O2 socket or an offset wrench, with penetrating oil and a heat cycle. Cut the connector at the harness only if you're scrapping; unplug at the connector if you're selling. Never pull on the wire — it snaps the internal platinum leads.

Is oxygen / lambda sensors worth more working than as scrap?

A tested-working Denso or Bosch wideband AFR sensor is $20–40 used against 75 cents as scrap — 25–50× . Narrowband is about 13×. Sell the sensor, not the platinum.

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