Temperature gauge

1998 DODGE NEON
160,123 MILES • 2.0L • 4 CYL • FWD • MANUAL
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GREENCHEVYMALIBU
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Just recently my car Temperature gauge will climb to hot and sometimes it will start to ding. I can shut it off and start it back up and the needle will go back down. When I drive with a scan tool hooked up the Temperature never goes above 164. Voltage does not go down past 2.32 volts. Should I change the Thermostat since it's only reading the coolant at 164 degrees. OE temp for the Thermostat is 195 degrees. Could this be a coolant flow problem, Temp sensor but it seems to be reading fine. Voltage and temp isn't erratic, possibly the Thermostat is opening to soon?
Jan 13, 2017 at 10:05 AM
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HMAC300
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is the coolant full? if not check for a leak possible head gasket.
Jan 13, 2017 at 12:31 PM
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GREENCHEVYMALIBU
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Coolant is full
Jan 13, 2017 at 12:59 PM
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GREENCHEVYMALIBU
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There is no coolant leak and compression is good. All 4 cylinders are within 10 psi.
Jan 13, 2017 at 1:03 PM
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HMAC300
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ok then change the tstat as it's running cool then see what happens. make sure to use a 50/50 mix of dexcool
Jan 13, 2017 at 3:07 PM
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GREENCHEVYMALIBU
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I'll change the tstat and let you know what happens.
Jan 13, 2017 at 4:38 PM
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STRAILER
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Please let me know what happens so it will help others.

Best, Ken
Jan 18, 2017 at 5:57 AM
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GREENCHEVYMALIBU
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Ok I replaced the thermostat and temp sensor. On the scan tool the temp is showing how it should now. I have a check engine light P0118 which is temp sensor voltage too high. I'm assuming I have a short some where. The car is getting hot. It's gets to 325 degrees and higher.
Jan 21, 2017 at 10:18 AM
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HMAC300
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if it gets that hot then have coolant system pressure checked for leaks as it may be head gasket. there is also a chemical for that. also check when hot an dengine off radiator for cold spots if any the rad is bad if system is full
Jan 21, 2017 at 12:27 PM
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GREENCHEVYMALIBU
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Pressured up the cooling system. Held 16 lbs for over an hour then started to bleed down a little. Did a compression test again and still has good compression. When I let it idle and the temp goes up the upper radiator hose stays cold also I notice that the radiator is cold too at least the top part not sure at the bottom. I can hold it with my hand and it's cold. Scanner reads 330 degrees and the upper hose and radiator are cold to the touch
Jan 23, 2017 at 1:14 PM
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HMAC300
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because of the code the temp reading is wrong an dcar seems to be not warming up check resistance of wire to pcm if over 5 ohms it's not doing any good as well as check connections. there is something there that isn't being said that I can see because this should have been broomed a long time ago.
Jan 23, 2017 at 3:26 PM
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GREENCHEVYMALIBU
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So on further inspection I have found the pigtail going to the coolant temp sensor was very corroded. Cleaned the prongs on the sensor and ordered a new pigtail. Comes in today.
Jan 24, 2017 at 1:39 PM
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HMAC300
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ok that may be the problem giving you a false reading then. that happens because sensor leaks coolant and gets on wires
Jan 24, 2017 at 3:05 PM
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GREENCHEVYMALIBU
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Ok so I though I had this fixed. Found a pin hole on the plastic tube that goes in to the back of the water pump. Changed the tube retested the system. Bleed all the air out. Drive it on Saturday for 7 hours no problems at all. Drove it this morning and temp would go up when I would rev higher through gears then go back down up it would go up around 3/4 ok the guarded. Is that normal? I have a mishimoto radiator lying around. Would that help with the temp since it is an aluminum radiator and bigger then the factory radiator?
Mar 13, 2017 at 12:18 PM
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HMAC300
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try a different radiator the only thing I can think of at this point is that the water pump impeller may be slipping on shaft.
Mar 13, 2017 at 12:21 PM
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GREENCHEVYMALIBU
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That's possible I replaced in since it was leaking but it's an autozone water pump so it wouldn't surprise me if it was bad out of the box.
Mar 13, 2017 at 12:24 PM
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GREENCHEVYMALIBU
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What is the normal operating temperature suppose to be? When I check my temp with my scan tool is 320 degrees Fahrenheit. My guage reads that it is normal and not running hot.
Mar 14, 2017 at 11:18 AM
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HMAC300
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pu tone of those cheap infrared hand held digital temp gauges on the top heater hose when hot and see what the temp is if it's around 210 then it ok if you scan tool reads the high temp then get your tool checked its off
Mar 14, 2017 at 11:51 AM
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GREENCHEVYMALIBU
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Checked the temp on my car after work. Car had been sitting for 9 hrs. Temp was reading 188 degrees. When you unplug the pigtail the temp jumps to 290 degrees 5volts. With isn't right. Checked the wire from the pcm harness to the temp sensor and it reads .2 ohms and beeps. No break in that wire. At this point I'm assuming it's electrical. I swapped out the pcm with a known working one and it didn't change the temps. Thought maybe the pcm was sending the wrong reference voltage.
Mar 25, 2017 at 9:24 AM
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HMAC300
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have you used the infra red temp thing like I asked a few replies ago on top hose to see if that reads a different temp? it may be a bad wire leading to the gauge or a grounding problem with dash I really can't think of anything now
Mar 25, 2017 at 9:32 AM
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GREENCHEVYMALIBU
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I'm still planning on using ir temp gun on the top hose. Haven't had a chance to pick up an ir gun. Going to pick one up on my next day off work.
Mar 25, 2017 at 1:27 PM
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STRAILER
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Please let us know what happens.

Best, Ken
Mar 28, 2017 at 1:31 PM
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GREENCHEVYMALIBU
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I fixed it. Sorry for the very late response. It ended up being a ground wire. The bolt that holds it down was broken in half and was arcing cause (causing high resistance) the guage to be irratic. Replaced the bolt and the problem went away.
Jul 2, 2017 at 4:06 PM
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HMAC300
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figured it had to be something like that least you got it fixed.
Jul 2, 2017 at 4:36 PM
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STRAILER
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Nice work, we are here to help, please use 2CarPros anytime.

Cheers, Ken
Jul 2, 2017 at 7:25 PM