Engine Sending Units (oil & temp)

Discussion in 'Chevy C/K Truck Forum' started by K15 Blazer Guy, May 25, 2012.

  1. K15 Blazer Guy

    K15 Blazer Guy Member 2 Years 100 Posts

    How commin is it for these sensors/sening units to fail on our trucks?

    'cause my oil temp gets lower and lower as the motor warms up.... and i dont think the water temp reflects the engine's water temp... cause you touch that upper hose & its HOT.
    but i figure the guage only reads...160?

    and it the sensor tells the computer the temp is 160, its gonna be a little less economical on gas. cause these motors are engineered to run hot...

    wish i had a point and click lazer thermometer lol! but theyre like....$300
  2. Big6ft6

    Big6ft6 Rockstar 100 Posts

    The sensor for the water temperature gauge is not the same as the sending unit for the water temp to the computer. They are two different sending units. Just because your gauge is showing 160 doesn't mean that is the signal that the computer is getting.

    But to answer your questions, both can go bad. The one that send the coolant temp the computer is called the "coolant temperature sensor" or CTS and if it gets out of expected range it will light up your check engine light. It is possible that if is only off a little bit and it would cause your fuel to run just a tad bit richer because this is what the fuel injected engines do instead of having a choke.

    But I think when they fail, they fail badly and go out of range, they don't just go off a little bit. For example, when my CTS failed, my truck ran really rich, so rich that it wouldn't start if I shut the engine off after it was warmed up because the fuel mixture would be rich it would flood. The signal it was sending would've been the equivalent to -160F (or something crazy I can't remember exactly).

    I'm not familiar with oil temp gauges, but all the senders can go bad, and so can the gauges themselves.

    You can get a laser point and click thermometer at Harbor Freight for $29 when they're on sale. And they work great for exactly what you're think to use it for. I have one.
  3. K15 Blazer Guy

    K15 Blazer Guy Member 2 Years 100 Posts

    oh wow, only $30? thats awesome!

    yeah that makes sence then. im sure the water in just fine, cause it starts and drives great. but that oil one is done.
    there is no way i have 5psi of hot engine oil... i think i wouldve noticed that by now...
    also, when i had my flashers on yesturday, both the volt needle and oil needle were pulsing... so yeah... gotta be a bad sensor

    thanks dude!

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