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My temp gauge in my 94 dodge ram is reading hot. The gauge climbs slowly like it is actually reading temp all the way up to 260 (redline) but laser shows engine running between 190-210 I have replaced the sensor that sends temp to the computer and the one that sends temp to the gauge and the problem still occurs any suggestions?

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Does the gauge climb if the sensor is disconnected ?

Posted on Jul 12, 2013

  • 12 more comments 
  • Ben Ruth Jul 12, 2013

    No when unplugged gauge is completely bottomed out

  • Ben Ruth Jul 12, 2013

    I have also removed the thermostat flushed the system checked for head gasket leak replaced both sensors and made sure water pump and fans are operating correctly before I checked temp with laser and the laser shows temp going into the radiator at the top hose at 190-210 and coming back out at the bottom hose between 120-135

  • Ben Ruth Jul 12, 2013

    And those temps are when gauge is reading 260

  •  Stephen
    Stephen Jul 12, 2013

    Well since you replaced the sending unit, you know the engine is not running hot, and the circuit is not shorted to ground, I would say the gauge on the dash is the problem. The temp gauge and gas gauge get power from the same source, so if the gas gauge reads normally its not a power problem.

  • Ben Ruth Jul 12, 2013

    I just went and got an aftermarket temp gauge and ran it to new ground and power source and it came with new sensor to install that it runs to and the new gauge is doing the same thing but the temp at the radiator is still reading good on two separate lasers I'm completely lost on this problem coolant is not boiling out or making any noises that normally happens with an overheating engine but this is 2 separate gauges and 3 sensors that show its overheating

  •  Stephen
    Stephen Jul 12, 2013

    Interesting. The sensor grounds the old gauge, does it ground the new gauge too ? I wonder if something is going on with the liquid coolant, causing extra electrical current some how. Or something strange going on with the grounding of the engine block to the frame. The sensor is supposed to have a resistor inside and the coolant temp affects the amount of resistance between the gauge and ground at the intake.

  •  Stephen
    Stephen Jul 12, 2013

    You could run a temp ground wire from the block to the frame to make sure that connection is good, but if it was not, the starter and alternator should also have problems.

  •  Stephen
    Stephen Jul 12, 2013

    Using an inferred temp sensor is not 100% accurate since you are not measuring the same thing (coolant) that the temp sensor is, but it should still be close enough to be used as a guide. If the radiator was low on coolant, the sensor usually reads low instead of high since it needs liquid coolant to get the reaction.

  •  Stephen
    Stephen Jul 12, 2013

    And I am assuming you used new wiring that came with the new gauge kit.

  •  Stephen
    Stephen Jul 12, 2013

    Does the new gauge start out at cold, and then start going up after the engine has been running for some time ?

  •  Stephen
    Stephen Jul 12, 2013

    And how long does it take the temp sensor to reach normal temp using the inferred thermometer ? And is the temp of the sensor close to the temp of the upper radiator hose ?

  • Ben Ruth Jul 12, 2013

    I used all new wire that came with the new gauge and the sensor that came with it replaces the stock sensor and then it has a hot wire that runs to the fuse box and a ground wire which I ran to the frame it starts at 0 and slowly climbs this one took about 20-25 minutes to read hot which is about twice as long as the other gauge but the problem is still occurring temp on the engine where the sensor is located read 207 with the laser while the gauge is reading 280

  • Ben Ruth Jul 12, 2013

    I'm at a shop now they are running a machine to make sure there is no air anywhere in the system

  • Ben Ruth Jul 12, 2013

    That didn't work either I'm at a loss



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Posted on Jan 02, 2017

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Probably the temp gauge itself. Most of the time it doesn't have a problem but sometimes they do go bad. Did the car ever overheat prior to changing the solenoid?

Posted on Jul 30, 2009

  • 94 Answers

SOURCE: Temperature gauge almost redlining

What engine does your Ram have? This could be an indicator of a bad head gasket. If the sensor for the gauge is truly bad, the only way test that theory is to install an aftermarket gauge, use an infrared temp sensor on the water outlet hose or replace the coolant temperature sensor. If this doesn't help, you may need to take it to a mechanic and have them do a leakdown test. Failed headgasket can cause bizarre overheating issues. Good luck.

Posted on Jul 07, 2009

  • 13 Answers

SOURCE: 2002 malibu runs hot.

Sounds like you have a faulty head gasket or maybe a cracked head.This can cause overheating and the check engine light to come on.The code for the o2 sensor is probably caused by coolant getting into the exhaust system and coating the sensor.The coolant fan may work but it cannot remove enough heat from the rad to make the engine cool off.Try some engine coolant stop leak to see if it will help.This maybe only a temperary fix.Let me know if you need more.MOE

Posted on Jun 22, 2010

  • 720 Answers

SOURCE: 1990 honda accord temp gauge above hot limit.

Hi there,

Firstly - DO NOT run engine, when guage reads hot, as this will cause costly damage to head gasket & alloy engine head.

The fact that guage takes 1min to read HOT, would confirm the guage IS working properly.

So, other components which are likely to cause hot readings (in this order) are:

- lack of coolant (or leakage somewhere): is there sufficient green coolant at the correct level? Top up mixture to correct level. Repair any leaks.

- collapsed radiator hose: when engine is cold, start engine, then quickly watch both upper & lower radiator hoses to see if either begins to flex inwards (collapse). Replace if either hose is collapsed.

- bad/incorrect thermostat rating : when replacing thermostats, you must ensure it is of the SAME temp rating (they all differ).

- Incorrect Temp sensor rating: the ratings of this sensor must be within manufacturer's spec's.

- bad waterpump: the engine relies on the waterpump to distribute the coolant throughout the entire system. If waterpump is faulty, coolant will not flow quick enough, causing overheating.

If you still believe all of the above components are OK, then have your cooling system "pressure tested". This test should be done, before looking further at other electrical components.


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