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Thread: engine temp issue maybe

  1. #1
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    engine temp issue maybe

    i have my coolant temp gauge sensor in the intake and the gauge read exactly 180 as per the thermostat and the comuters sensor is in the cylinder head and on tunerpro it reads between 192 and 195 is that normal or should they read the same and i need to search for a problem.can headers make a differance in what the readings are?

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    I'd think it's OK. The gauge could be a little low and the heads right at the exhaust ports can be hotter than at the thermostat.

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    Quote Originally Posted by bonnieclyde100 View Post
    i have my coolant temp gauge sensor in the intake and the gauge read exactly 180 as per the thermostat and the comuters sensor is in the cylinder head and on tunerpro it reads between 192 and 195 is that normal or should they read the same and i need to search for a problem.can headers make a differance in what the readings are?
    What engine is it? 1994 LT1? OR LS? Or?

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    its a 1993 chevy 350 out of a pickup truck put in a 1969 chevy truck
    Quote Originally Posted by billygraves View Post
    What engine is it? 1994 LT1? OR LS? Or?

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    considering how accurate the average dash guage is, i'm much more inclined to believe what the ECM is spitting out.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


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    cylinder head coolant temp is a function of both coolant temperature and combustion temperature, as the heads are a fairly direct heat sink for combustion heat.

    just 'cause your coolant sensor is in coolant doesn't mean it doesn't measure the heat of what it's threaded into as well.

    the intake is not a direct heat sink for combustion temperature. as such, coolant temperature in the intake is much more consistent with coolant temperature.

    so these results are not suprising.

    headers shouldn't make a difference, nothing bakes a sensor like tightly fit cast iron manifolds

    having the ECM's temp sensor in the head is weird to me, most of the time in a factory configuration it's in the waterpump or intake or something, and your gauge sensor is in the head (not that it really matters where your gauge sensor is, it's just a gauge)

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    Quote Originally Posted by steveo View Post
    cylinder head coolant temp is a function of both coolant temperature and combustion temperature, as the heads are a fairly direct heat sink for combustion heat.

    just 'cause your coolant sensor is in coolant doesn't mean it doesn't measure the heat of what it's threaded into as well.

    the intake is not a direct heat sink for combustion temperature. as such, coolant temperature in the intake is much more consistent with coolant temperature.

    so these results are not suprising.

    headers shouldn't make a difference, nothing bakes a sensor like tightly fit cast iron manifolds

    having the ECM's temp sensor in the head is weird to me, most of the time in a factory configuration it's in the waterpump or intake or something, and your gauge sensor is in the head (not that it really matters where your gauge sensor is, it's just a gauge)
    the factory 93 chevy has the ecm sensor in the intake and the gauge sensor is in the head. i have an edelbrock intake and the hole is a little larger than the factory intake and rthe sensor i have for the gauage fits that hole that why i have the ecm sensor in the head. i wish therewas a way to put bothe sensors in the intake.

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    haven't you ever heard of brass pipe thread reducers?

    they're like $0.50 at any good hardware store.

    you can always put a small sensor in a bigger hole.

    you can always use a pipe thread T fitting to accomidate both sensors.

    or tap a new hole in a coolant passage.

    or get a different thread size GM temp sender (most are the same specification)

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    Quote Originally Posted by steveo View Post
    haven't you ever heard of brass pipe thread reducers?

    they're like $0.50 at any good hardware store.

    you can always put a small sensor in a bigger hole.

    you can always use a pipe thread T fitting to accomidate both sensors.

    or tap a new hole in a coolant passage.

    or get a different thread size GM temp sender (most are the same specification)
    yes i have heard of reducers but the gauge i have is aftermarket and the sensor is to big to screw into the head where the factory put them. i may have a solution the picture below shows a spot on my intake i think i can drill and tap for a sensor. what do you think?
    Attached Images Attached Images

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    Ya, that's a perfect spot to tap for a sensor.

    But why bother? If it's working fine then leave it like it is.

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    Quote Originally Posted by bonnieclyde100 View Post
    the factory 93 chevy has the ecm sensor in the intake and the gauge sensor is in the head. i have an edelbrock intake and the hole is a little larger than the factory intake and rthe sensor i have for the gauage fits that hole that why i have the ecm sensor in the head. i wish therewas a way to put both sensors in the intake.
    Easy problem to solve, just use a LT1 sensor. It has 3 pins, 2 for the ECM and 1 for the gauge. Uses a later model T shaped TPS connector.

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    the LT1 uses no such sensor, lt1 temperature sensor config is as follows, two wire on waterpump (ground/signal), one wire in head (for gauge), two wire IAT in intake elbow, and oil temp on y-body only. must be thinking of a different engine.

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    Quote Originally Posted by steveo View Post
    the LT1 uses no such sensor, lt1 temperature sensor config is as follows, two wire on waterpump (ground/signal), one wire in head (for gauge), two wire IAT in intake elbow, and oil temp on y-body only. must be thinking of a different engine.
    It was a mid 90s D car I first saw it on. Fleetwood or Roadmaster, can't remember which.

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    well i drilled and tapped the new hole for the sensor it worked great . i really wanted to do this because i want to use a 195 degree stat and with that stat the computer thought the engine was well over 200 degrees now it is showing the same as the gauge.

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