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208D (OM601.940) coolant sensor location

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by jospanner, Sep 15, 2020.

  1. jospanner

    jospanner New Member

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    Your Mercedes:
    208D, 1991, OM601
    Hi, I'm trying to find the coolant sensor on this engine. That might sound like a silly thing to have trouble with, but I can see two things that look like the candidate, and neither are it.

    The actual problem I am having is that there is no heat and the temp gauge doesn't move. To me that says "thermostat", so of course I want to do that, but I also wanted to replace the sensor at the same time. That made sense until I tried to find it, and couldn't, and now I'm annoyed.

    I have found one sensor mounted on the thermostat housing - the wire routing and colour suggests this one is to do with the glow plugs. It has no continuity to the sense wire on the temperature gauge. This sensor has a single connector on it (some of the ones that pop up online have multiple connectors).

    The only other thing that looked like a sensor was towards the rear of the engine, which appears to be an oil pressure switch. No continuity.

    According to my wiring diagram (and the gauge), I am looking for a blue/lilac wire. I really thought it was on the thermostat housing, but there is only one sensor there that I can see, and that doesn't seem to be it. Can anyone help?
     
  2. clarkmichigan55b

    clarkmichigan55b Senior Member

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    Location:
    sunny Surrey on a sunny day
    Your Mercedes:
    Mercedes 208D T1 van 1989
    Hello,

    Just had a quick look on my van and internet parts look up and it would appear to be on the inlet manifold side on the cylinder head just behind the injection pump. I will have a look at my workshop manual tonight to confirm this and let you know tomorrow.
    Adrian.
     
  3. clarkmichigan55b

    clarkmichigan55b Senior Member

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    Your Mercedes:
    Mercedes 208D T1 van 1989
    This my be of help to your sensor location number 149
    Adrian.
    208D.png
     
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  4. OP
    jospanner

    jospanner New Member

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    Your Mercedes:
    208D, 1991, OM601
    Aha, thank you! I'll have a look tomorrow and report back. That would explain why I couldn't find it.
     
  5. OP
    jospanner

    jospanner New Member

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    That's the job, I found it just fine!
    A question though, where do you find diagrams like that, for these engines? It would be really useful to have later on.
     
  6. clarkmichigan55b

    clarkmichigan55b Senior Member

    Messages:
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    Location:
    sunny Surrey on a sunny day
    Your Mercedes:
    Mercedes 208D T1 van 1989

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