So i replaced my coolant temp sensor (ej251) with a Intermotor part (#tx85) from RockAuto,

 

well. the car seems to be running fine far as i can tell, but after the replacement, my ea dash gauge is pegged to the top! i removed the resistor i had in parrallel with the circuit to the gauge to see if it would make a difference, and nope, no change as i kinda thought.

 

only way i can get the gauge down is by putting a resistor in series with the gauge.

 

i havent experimented at all what resistance is needed to make it work properly. but i find this pretty odd.

 

Do you think I got the wrong part? or maybe the parts bad? (or is that just the way it is with this replacement part.. for those that may have used it. )

Hmmm......

 

aren't those the triangle ones int he later years with both Gauge and ECU signal built into one sender? Perhaps you got the triangle rotated? Hard to imagine but just a thought.

 

Otherwise, I'd say bad or incorrect sensor.

weird indeed. I'd be tempted to say bad ground connection, but....how could that happen? is one of the wires ground and it's open inside the insulation? Or, if it grounds through the block, was it installed with teflon tape?

F'in a.

 

I did put Teflon tape on it, went back and forth on to do so or not.. Its a triangle sensor, However it only fits one way by design. There is a notch that prevents putting it wrong unless you mangle/force it.. However I would have thought that the coolant tune was Aluminum so it wouldn't ground thru it?? Ill take the Teflon tape off and try it.

F'in a.

 

I did put Teflon tape on it, went back and forth on to do so or not.. Its a triangle sensor, However it only fits one way by design. There is a notch that prevents putting it wrong unless you mangle/force it.. However I would have thought that the coolant tune was Aluminum so it wouldn't ground thru it?? Ill take the Teflon tape off and try it.

 

 

let us know OK? I've never changed one and am having a hard time imagining how it fits. It probably uses the wires for ground so, the teflon may not be the issue - as far as electrical connection anyway.

 

aluminum is a great conductor. and while it does create a layer of oxide on exposure to air (sapphire actually!), that layer is quite thin and typically won't insulate terribly well. .

theres 2 wires and 1 gnd on the sensor, i bet you that the gauge is grounded thru the coolant tube, not the gnd in the connector. that makes sense to why the car is driving as it did previously. and the gauge just doesnt work right.

 

i'll try removing the teflon tape and then will report back.

removed the teflon tape and there was no change in the way the sensor was reacting, so fortunately it was monday today and went to the dealer (open til 8pm on mondays) and got a new sensor, cost 2x as much, but its much easier to return if needed. i can probably still return this one to rock auto

 

the new sensor worked out just fine. i wish i would have just accepted the fact i could have a bad sensor right off the bat! LOL.

 

Had to be that i got a wrong part, or rockauto listed the part for the wrong year.

 

looking closer the subaru part vs the Intermotor part were slightly different, the intermotor part was larger in general as far as the temperature probe.

removed the teflon tape and there was no change in the way the sensor was reacting, so fortunately it was monday today and went to the dealer (open til 8pm on mondays) and got a new sensor, cost 2x as much, but its much easier to return if needed. i can probably still return this one to rock auto

 

the new sensor worked out just fine. i wish i would have just accepted the fact i could have a bad sensor right off the bat! LOL.

 

Had to be that i got a wrong part, or rockauto listed the part for the wrong year.

 

looking closer the subaru part vs the Intermotor part were slightly different, the intermotor part was larger in general as far as the temperature probe.

 

weird, glad it's working though.