w126 300sel (1988) 02 sensor

[Gito]

Own a 1988 300sel (w126) and need to replace the 02 sensor.

The dealer gave me this part# 007 542 52 17 and is pretty expensive ($200 plus)

AMZon with part#13930 has this 02 sensor for $77.00 and part#13925 for $67.13
Ahauz with part# 13925 has the 02 sensor for $100.00 plus.

All part numbers above seem to be for my car.

I haven't pulled the 02 off the CAT but why is there 2 different part numbers for my w126

Please advise

 

[RooflessVW]

My advice is to use the OEM Mercedes part.

 

[Wolf359]

Rockauto lists the Bosch 13925 as the upstream sensor. Amazon is pretty bad for picking the right part numbers. I don't know about that car, but rockauto is only listing upstream sensors, maybe the second one is the downstream. Usually it's the upstream sensor that goes bad.

 

[Trav]

The Bosch 13925 is the actual OE part for this car, it doesn't use a post (downstream) O2.