Who manufactures MB original equipment Lambda sensors

[tesla6518]

I have just recently had a problem with my garage whom I have been using for years to carry MOT's and certain work beyond my 71 year old capability. Aug 2019 my CLC180K(2009) failed its MOT on Lambda sensor pre CAT. As it was there I asked them to do it. £300 pounds later I was regreting not doing it myself. Then the dreaded Covid hit and I was unable to leave the house as I have lung cancer, with the 6 month defferment on MOT's due to Covid my new test date was Feb 2021, the car had done 750 miles and yes again it failed on pre Cat lambda sensor. Now last time they stated that a Bosch sensor was fitted ( these are recommended to be changed at 250,000 miles) so what went wrong.
Well I was not going to pay another £300 odd as they said the warranty had run out, So I have done it myself and found that it was not a Bosch sensor fitted but an NTK 92512.
I am really peeved at being lied to and before I proceed I would like to find out who the Mercedes Benz OEM supplier is for this part.
Thanks in advance.

 

[mattkh]

The intense heat affects the wires in the connectors to these oxygen sensors. I feel they should be serviced every 50,000 miles regardless.

 

[tesla6518]

Mattkh, Thank you for the prompt reply, however you have not answered my original question. Who are MB OEM for this part?

Also I find it hard to comprehend the answer you have given. when removed the sensor had no signs of physical heat damage, I have yet to test the sensor for internal faults (but I have requested NGK test it for me). The position of the sensor cable is routed in such a way that it avoids heat sources or is located in a position that has an airflow, removing any heat. in the case of the CLC 180K (W203) the cable runs to the rear of the engine and straight down to the bottom of the automatic gearbox where it is held in place by a slotted bracket. When I removed the connectors from both Lambda sensors I found some oil in them which is another strange one. Why? Both connectors have seals on them to prevent the ingress of oil, water etc, also they are in such a position that oil cannot enter them and to confuse matters even more there was no sign of oil on the connectors or wires. also no oil leaks on car and protection panels completely clean and dry.

 

[mattkh]

Thank you for your detailed reply from which I have learnt a lot. A lot of companies make oxygen sensors. I do not know which one MBenz trust most.
It is nice to know that 'continuous improvement' has resulted in the wires to the extremely hot oxygen sensor being provided thermal insulation and cooling.
I am worried about your mention of oil in that area, a potential fire risk.

 

[tesla6518]

I have the sensors in front of me on the desk, they are straight from the vehicle and have not been cleaned. There is not a drop of oil on them and they are so clean, not a speck of dirt on my hands after handling them. So now my suspicion is towards tampering. Lately I have seen what I call "Covid profiteering" even on amazon. The garage I used to use, I have noticed I have now noticed they have increased their prices from £50 per hour to £60 a 20% increase. also they added 100% on the cost of the part.
I am 71 years old have a pacemaker, COPD, Lung cancer and pre-diabetes, so my life is restricted. But!! I will not let these buggers get the better of me I will now do all the work myself unless it is physically impossible for me.
I have done lots of work on MB's and am willing to pass on the knowledge. I also have the MB WIS software up to 2020 so just ask

 

[Wighty]

I fitted a Bosch O2 sensor last time I changed one on my E class , Bosch are a massive global company , can’t see any issues with them .
If you have an M271 engine , check the two round cam magnets on the top front of the engine , unplug their electrical connections and check for oil in the fitting . Oil can migrate from here to the lowest point which is the O2 sensor (I believe)

 

[Mr Greedy]

Bosch would be my guess, but it is a guess.
Any complex electrical bits, if I wasn't buying Merc direct and didn't know the manufacturer or couldn't find suitable advice, I'd go Bosch every time.

 

[tesla6518]

That,s what I did cheapest place Autodoc based in Germany got both genuine Bosch £112. delivery normally 3-4 days

 

[tesla6518]

Hi Wighty

No there is now way for oil to migrate to these sensor plugs and sockets, also have seals on them to stop ingress if water etc.

 

[Wighty]

Hi Wighty

No there is now way for oil to migrate to these sensor plugs and sockets, also have seals on them to stop ingress if water etc.

I only mention it because the M271 engine (not sure if that’s you , but it is me ) , oil “wicks” along the wire form the leaking cam magnets (the oil travels inside the wires) , and ends up in the front SAM and the O2 sensor .

 

[tesla6518]

I believe that was the C & E classes that happened to, they br5ought out a mod for that.

 

[LostKiwi]

It's all M271 engines.

The issue is not model specific.
The normal work around is to fit oil blockers at the cam sensor end.
The way the oil migrates is by capillary action within the wires. The oil blockers are a section of single strand wire inserted in the loom between the cam magnet and loom connection and these prevent capillary action carrying oil into the wires.