Temp gauge

[240sxnewbie]

I've noticed for the past couple weeks, when i'm driving (around in the city or on the highway) my temp needle goes up to hot, however, i know i'm not overheating...is there any reason why it does this?? oh, i have a 95 240 SX...thanks!

[Kreator]

Most likely thermostat or the tempreature sensor are bad... I believe thermostat is about $20, temp sensor is even cheaper..... But it might be something else. I'd say get it to a mechanic, or just replace those two and see what happens.

[HippoSleek]

If your temp gauge is going up above the normal range, you are overheating. You don't need steam coming from the radiator and for the gauge to totally be pegged.

Anyway, I don't think your problem is a thermostat. A therm. goes bad when the rubber gets too hard and it no longer closes. B/c it doesn't close, the engine is cooled too well and the temp remains low. *edit* Misnomer, below, knows of a stuck closed therm. so it can happen.

I'd bet your problem is low coolant or a bubble in the system. There is a bleed valve to get out bubbles. Find it, open it, run the motor, add coolant. If that doesn't work, a thermostat is a $5, 10 minute job.  If that doesn't work, take it in - it might be something else. Unfortunately, this is not the type of problem you want to screw up w/ b/c an overheated engine is bad!

*edit* - somebody's always gotta know the exception to the rule &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/blush.gif" border="0" valign="absmiddle" alt=':blush:'>

[silviase]

hey hipposlik I don't think you should be so definitive on the subject when there are so many varibles as to what may be causing the car to over heat. My suggestion is to change
the thermostat and then if that's not the problem test the radiator to see if it's cooling properly. (could be clogged)
check to see if you have optimal water flow by taking the cap off the radiator and have someone rev the engine, if you can see the water rush through the the coil system then. you may have a water pump that's going bad.

[misnomer]

Thermostats can get stuck closed, happened in my mom's truck back in the day.

Another basic thing to check while you're at it is the radiator cap. If it's not holding pressure, the coolant could be boiling, losing effectiveness, and causing your overheating. Does it look like any coolant has been splashing out of your coolant tank?

[Kreator]

Hrm, why are u guys so sure that the engine IS overheating? I had this problem on an s14 before, my sensor has gone bad and the needle constantly showed engine overheating. Changed the sensor, the problem disappeared... Now my ford has overheated sometime in october last year due to the leaky heater core (damn it was a pain to replace). And on that car you could see it overheating. Like if you hold your hand 20cm away from the hood closed, you could feel air being hot.... So if he says there is nothing suspicious about the engine then there might not be something necessarily wrong with the car.... I personally believe in that sensors go bad faster than hardware.... that's debatable though <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>

[ca18guy]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (silviase @ Mar. 27 2002,07:36)</td></tr><tr><td id="QUOTE">hey hipposlik I don't think you should be so definitive on the subject when there are so many varibles as to what may be causing the car to over heat. My suggestion is to change
the thermostat and then if that's not the problem test the radiator to see if it's cooling properly. (could be clogged)
check to see if you have optimal water flow by taking the cap off the radiator and have someone rev the engine, if you can see the water rush through the the coil system then. you may have a water pump that's going bad.</td></tr></table><span id='postcolor'>
And what makes your answer the definitive answer, if you notice Hippo's suggestion is the cheapest and easiest to try first, which is were I would start (you have to trust your gauges, if it say's your engine is heating up you trust it) If that did'nt work move on to the thermostat, then sensor then radiator, then just say screw it and drive the car over a cliff if you can't find the problem.

[HippoSleek]

I'm with ca18guy on the "trust your gauges" tip. &nbsp;s14 temp gauges are notoriously inaccurate b/c there is too wide an area of temperature that is in the middle, but when they rise it's usually really bad. &nbsp;I hadn't thought of the cap - just b/c I've never had one go bad - but it is a cheapie item to check out.

As for the sensor - it could be. &nbsp;Ditto a clogged radiator or heat exchanger. &nbsp;Or the water pump (although, those usually make noise). &nbsp;

At any rate and FWIW, my advice is to look at the cheapest most obvious things first - coolant level, bubble, therm., cap. &nbsp;Then, if you still have a problem and are no closer to finding it, it may be worth taking in unless you just want to start randomly replacing some expensive and harder to install parts. &nbsp;Then find a cliff <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'>

[Kreator]

On my s14 it tended to go up all the way to the top like 10 minutes after i started the engine, but the engine wasn't overheating (at least u couldn't notice it)... The thing that scared me at first was that the radiator was cool, so i thought thermostat was bad or something wrong with the pump.. Turned it in to the dealer (good thing i still was under warranty), they changed thermo, but then the problem was still there so they changed the sensor as well.... and i got a free thermostat &nbsp;even though it's only $20 <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'> I agree with checking out the coolant first though

[geeaj]

Yes, our temp gauges can become grossly inadequete. The reading you see may not be correct!

Some of the things the other posters suggested do have merit, you may want to get your coolant system pressure checked. This can help identify the pieces of the coolant system that may not be operating correctly.

Changing out the water pump, hoses, and thermostat is pretty easy. It took me about 1.5hours and that includes removing the fan shroud, clutch, being super meticoulous too.

If you radiator is all good, and you replaced your waterpump, thermostat, and flush n fill your coolant correctly (no air pockets), then its your temp gauge.