Overheating...

[dragon240sx]

Okay, well this seems to be my problem week. Not only is my fuel gauge needle going up and down randomly while I'm driving down the road, but the car is now wanting to overheat at random times. &nbsp;I was having this problem about 6 months back so I replaced both the temperature sensor and the thermostat and that seemed to solve the issue, but now, it's doing it again. The needle will go up to almost the H, freeze there for a moment, and then come back down. I also *think* it seems to do the overheating when I'm at lower RPM's (around 2200) but if shift down to a lower gear and bring the RPM's up, the needle seems to start coming back down quicker...of course that could just be some wierd coincidence. So what's going on...water pump trying to die...the fan not wanting to come on...any clues? &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>

[Jeff240sx]

Yea... I was gonna mention that since it was rpm related, to check your water pump and fan. &nbsp;But you already mentioned those, so I think you're right. &nbsp;
-Jeff

[dragon240sx]

Is there any way to "analyze" the problem or just go ahead and be safe and by a waterpump and put it on...oh I did leave out, the car has 150,000 miles on it and it's a 96

[Tyler Durdan]

Another thing it could be is you are low on oil. &nbsp;This could be caused from an unknown oil leak. &nbsp;When you downshift, you are uping the rev's causing the mechancial fan to turn faster. &nbsp;Check the waterpump, oil, and possibly the coil.

[dragon240sx]

Well the oil is fine, I made sure the antifreeze was full, and I started the car up just to make sure the fan was running at all and all three are o.k. Question 1, is there a "clutch" on the fan that could go bad and make it stop spinning while I'm driving down the road, and question 2, can water pumps slowly die because any experience I've had with them is they just go bad suddenly and without warning. Could the "blades" or whatever inside the water pump that push the water out wear down and stop pushing as much water at the lower RPM's?

[mrmephistopheles]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (dragon240sx @ Nov. 26 2002,9:22)</td></tr><tr><td id="QUOTE">Well the oil is fine, I made sure the antifreeze was full, and I started the car up just to make sure the fan was running at all and all three are o.k. Question 1, is there a "clutch" on the fan that could go bad and make it stop spinning while I'm driving down the road, and question 2, can water pumps slowly die because any experience I've had with them is they just go bad suddenly and without warning. Could the "blades" or whatever inside the water pump that push the water out wear down and stop pushing as much water at the lower RPM's?</td></tr></table><span id='postcolor'>
1. Yes.
2. Yes. Mine died at 153k miles. Replaced with an OEM Nissan pump. Next water pump change should be ~306k miles. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>

Kevin

[95Blue240sx]

i notice my car does the same thing too. &nbsp;but i removed my fan clutch, the one connected to the engine. &nbsp;my elec fan comes on when it needs to and i also have a manual switch to turn it on when i want. &nbsp;i changed my thermostat, but not my temp sensor. &nbsp;i just hit 100k. &nbsp;another possibility is that there might be corrosion in the radiator. &nbsp;id go with that before changing waterpump. &nbsp;i havent done so because my car has gone back to normal. &nbsp;i changed the thermostat at about 80k. &nbsp;thats my 2 cents on it. &nbsp;let me know if you figure it out. &nbsp;

one more thing, did you get an oem nissan temp sensor? &nbsp;or something from like kragens?(i hate kragens!!!<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt=';)'>

[dragon240sx]

Yeah i got both the temp. sensor and thermostat from Nissan...I'm just keeping an eye on things right now. I drove an hour home from college today and didn't have any problems but if it does it again I guess I'll start with replacing the fan and then if that doesn't work I'll just replace the waterpump. When I changed the parts before I flushed the radiator and put new coolant in it so it "should" be clean, haha. Thanks for the tips though!