Second opinion

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by TrailLeadr, May 22, 2007.

  1. TrailLeadr

    TrailLeadr Epic Member 5+ Years 1000 Posts

    I talked with Jamie about this at length, and he seems to feel he's found an answer. But I'd like a second opinion on what this is. I don't want to say what we think it might be, because I don't want people to simply agree.

    When I sent my heads out for my rebuild, I hadn't pulled the sensors or plugs, since I didn't want the holes to rust up before they were worked.
    Anyway, when I got the heads back all sensors and plugs were pulled. Which would normally not be a problem, but I have no idea what the heck these sensors were.

    I know that they are not coolant temp sensors(hole's too big), knock sensors, or oil sending units (wrong location).
    They thread into the water jacket of the head, and the connector is to a single wire.

    The sensor goes here, as indicated by the arrow in the picture. Both heads have this same hole, and each had a sensor. So any ideas?

    Thanks in advance:great:

    Attached Files:

    Last edited: May 27, 2007
  2. Crawdaddy

    Crawdaddy All hail the Mad King!! Staff Member 5+ Years 1000 Posts Platinum Contributor

    when my uncle got his 454 heads back form the shop, that same hole had nothing in it. There was one head that had a plug in it, and the other one simply had a hole. He eventually found the sensor that he had removed, but forgot about. I think the sensor was a water temp sensor, but I don't think we even figured it out. When I get over to his house, I'll try to take a pic of the hole and the sensor.
  3. TrailLeadr

    TrailLeadr Epic Member 5+ Years 1000 Posts

    If you can get a pic that would be great!:great:
    I won't plug the holes, as I do have wiring that goes to the sensors that used to be there. OBDI is terribly inefficient in my opinion, I don't want to give it a reason to be worse by not installing the sensors. Not to mention the CEL/SES will be on, and that will make me crazy:lol:
  4. TrailLeadr

    TrailLeadr Epic Member 5+ Years 1000 Posts

    That's it then? No one has any other ideas, or knows what it is?
    I guess I'll have to call the dealer on Monday.
  5. unplugged

    unplugged Epic Member 5+ Years 1000 Posts

    Temp sensor location

    If you are talking about the port between the center exhaust ports, it is for a temp sensor, that is used on the driver's side, and plugged on the passenger side.
  6. TrailLeadr

    TrailLeadr Epic Member 5+ Years 1000 Posts

    I am referring to that, but both of the heads had sensors, and I have wiring for both, that and the temp sensors I bought match the sensor on the manifold. There doesn't appear to be a different temp sensor option out there.

    So general consensus is that it's a temp sensor. Now I just need to figure out what the part number is.

    Thanks unplugged, and Crawdaddy!:great:

    Once I get the part#, and relevant info, I'll post it here for future ref.

    One of the things that throws me off, is my schematics do not show these sensors.
  7. unplugged

    unplugged Epic Member 5+ Years 1000 Posts

    There can be only one

    The temperature switch that goes in the drivers side is available from AutoZone pn: TU169 $11 I don't have a BB to look at, but I am not aware of any sensor on the passenger side.
    1 person likes this.
  8. TrailLeadr

    TrailLeadr Epic Member 5+ Years 1000 Posts

    It's probably the same sensor. At least I hope so, since that's what I'm going to buy, is two of them.
    I would gladly save myself the $$ and buy only one, but since I remember a sensor on the pass side, plus the wire is there, I will have to get two.

    Thanks again for the part # that's a huge help!:great:
  9. Cableguy

    Cableguy Epic Member 5+ Years ROTM Winner 1000 Posts

    All these endless truck parts. Patrick we have other expenses you know!...Sound familiar. Ya grab a blanket/pillow and fight the dog for a good spot on the couch. :lol:

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