Walker Products 350-33018 oxygen sensor for the 1986-1991 Mercedes-Benz 420SEL V8 4.2L and other vehicles measures the oxygen in the exhaust gas to show how efficiently the engine is burning fuel. This Walker Products oxygen sensor is a 3-wire, direct-fit, narrow-band unit made for its specific application and fitting position.
- Monitors exhaust gases to help reduce pollutants
- Coating protects the electrode surfaces from contamination and erosion by combustion residue and particulates
- Reads exhaust oxygen content to monitor the air-fuel ratio and combustion efficiency
- Electrodes coated with a gas-permeable platinum layer
Quick facts
- Part: Walker Products 350-33018 oxygen sensor
- Fits: 1986-1991 Mercedes-Benz 420SEL V8 4.2L and other vehicles
- Position: Upstream
- Condition: New
A failing sensor can show up as a rough-running engine, higher fuel use, higher exhaust emissions or a lit malfunction indicator light. These signs alone do not prove the sensor is at fault, since an exhaust leak near the sensor can cause some of them too. With the engine off and cool, look over the sensor, wiring harness and connector for damage.
Fits
This upstream sensor also fits the 1986-1991 Mercedes-Benz 560SEC V8 5.6L and the 1986-1991 Mercedes-Benz 560SEL V8 5.6L, and any of these cars takes one sensor.
Specifications
Fit and size
- Position: Upstream
- Quantity per vehicle: 1
- Thread: M18 - 1.5
- Wires: 3
Build and materials
- Type: Narrow-band, direct fit
- Electrodes: gas-permeable platinum layer
- Condition: New
Product information is for general reference and may contain errors. See our Disclaimer.
Frequently Asked Questions
Is this the right Mercedes 420SEL oxygen sensor for a 1986-1991 Mercedes-Benz 420SEL V8 4.2L?
Yes. Walker Products 350-33018 is an upstream sensor for the 1986-1991 Mercedes-Benz 420SEL V8 4.2L and fits other vehicles too. Check your own car in the "Vehicles it fits" section.
What thread and wire count does this narrow-band oxygen sensor have?
The Walker Products 350-33018 has an M18 - 1.5 thread and three wires. It is a narrow-band, direct-fit sensor.
Is this oxygen sensor an upstream or downstream unit?
This oxygen sensor is an upstream unit, and the vehicles it fits take one sensor each.
What signs can a failing oxygen sensor show?
The engine can run poorly, fuel use and exhaust emissions can rise, or the malfunction indicator light can come on. Damaged wiring or a damaged connector can also be seen with the engine off and cool.
What does the coating on this oxygen sensor do?
The coating prevents contamination and erosion of the electrode surfaces by combustion residue and particulates in the exhaust gases. The electrodes carry a gas-permeable platinum layer.
