Thread: Overheating?

1991, JDM highport motor, pretty much stock.

Person who installed the motor can't remember if he used the JDM temperature sensor for the gauge or swapped over the sensor from the old motor. The gauge generally reads around the "C" mark most of the time, but while sitting at a stop light it climbs up to around normal temperature. Start driving again, and it drops down to just above "C".

Now, I'm having a hard time trying to determine if the gauge is all wonky or if the car is overheating. The fan kicks on like it should.

Not sure what ratio of antifreeze/water is in there either, but I may flush it out this weekend and put a 30/70 mix in with a bottle of water wetter. Also plan on purchasing a used A/C fan from a Sentra E at the junk yard so that I have two fans kicking on when needed.

Opinions?

the engine coolant temperature gauge and the dash gauge are two seperate sensors.

I know...

But since the fan is working like it should, (I believe) then the gauge sensor is off? Maybe the gauge itself?

in short: yes.

the sensor is uber easy to change and costs about $15. It's called a coolant thermistor, I'm sure you can source it at rockauto - replace that first, then if that doesn't work, tackle the gauge replacement.

You can see the photo of what the thermister looks like in my ect thread in the 'how to' section. It's the smaller one with one wire going to it, a spade connector. Lost of people have had their wire go funky before the thermister, so take it off carefully, clean the contacts, and reconnect. No sense spending money you don't have to.

Yah, that spade connector goes bad all the time on Nissans. I rip them off leaving a nice stub that an alligator clip will grip nicely for centuries.

who told gram he was wrong ?

lol wtf?

how the hell did that get posted in this thread ? weird...........

canx2k is right -- the temp gauge sensor is cheap and easy to replace. Do that first. If that doesn't fix it, here are a couple of ideas for diagnosing.

1. If you have a Consult cable and laptop you can monitor engine temp according to the coolant sensor that the ECU reads (not the gauge sensor) to try and make sense of what the temp gauge is doing.
2. You could use a thermometer (or IR gun) to read the actual temperature of the coolant at the radiator (or hoses with the IR gun). BE CAREFUL if you open the radiator when the engine is hot.
3. Check/replace thermostat.

more like DONT open the rad with the engine hot - scalding green stuff sucks.