crunkGP96 Posted February 14, 2020 Report Share Posted February 14, 2020 Hey all, it’s been a while since I’ve posted much. Still have my 95 GTP running strong. I’ve got sort of an issue with it though. My coolant temp gauge goes all wacky when I drive it on the highway in colder temperatures. I’ve been told twice by two different shops that the car isn’t overheating. I just replaced the thermostat and it’s doing the same thing. Both coolant hoses have pressure and no air is in the system. Car runs fine but that gauge freaks me out when I drive on the highway and it skyrockets to 3/4 temp or even to full sometimes with the heater on. What’s goofy is that it’ll all of a sudden come down when I’m stopped or slow down lol Heat works good, car isn’t overheating from what I see and have been told. Fans are working from what I can tell as well. What could it possibly be? Temp sensor maybe? Bad wire? Most recent pic of my car still looking decent [emoji846] Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Amanita Posted February 14, 2020 Report Share Posted February 14, 2020 (edited) I wish my '96 looked as good as yours. If your car was a '96 as well it might be easy to diagnose with an obd2 scanner monitoring the coolant temperature, but my best guess is the gauge is starting to become faulty. How high does the coolant get in the overflow tank after you've driven it for a while? That might be the easiest way to check if you're overheating. Edited February 14, 2020 by Amanita crunkGP96 1 Quote Link to comment Share on other sites More sharing options...
Psych0matt Posted February 14, 2020 Report Share Posted February 14, 2020 Sounds like a temp sensor or the gauge (though less likely), and since the sensor is cheap and easy, probably start there. Amanita and crunkGP96 2 Quote Link to comment Share on other sites More sharing options...
digitaloutsider Posted February 14, 2020 Report Share Posted February 14, 2020 The only thing concerns me is that it's directly related to whether or not there's load on the engine. Either way, the coolant temp sensor is cheap; replace it and see where it gets you. Looks like the actual GM one is only $15 on RockAuto. Psych0matt and crunkGP96 2 Quote Link to comment Share on other sites More sharing options...
crunkGP96 Posted February 15, 2020 Author Report Share Posted February 15, 2020 Thanks for the replies guys, going to buy the sensor tomorrow and take it from there. Were exactly is the sensor located? Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Psych0matt Posted February 15, 2020 Report Share Posted February 15, 2020 Should be on the side of the radiator, drivers side. It has a clip and a plug. crunkGP96 1 Quote Link to comment Share on other sites More sharing options...
crunkGP96 Posted February 15, 2020 Author Report Share Posted February 15, 2020 Ahhh I remember the radiator one now. Is there one on the block as well? Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Cutlass350 Posted February 15, 2020 Report Share Posted February 15, 2020 (edited) Does your car have OBD-II or is it GM OBD-1 (1-1/2)? You need to look at the real time data. You have one coolant temperature sensor. If the temperature sensor (or the wiring) is flaky/bad, it would/will effect the EFI. It could be also be the gauge, any wire to the ECM or gauge, etc. On my 2000 Intrigue, my temperature gauge is controlled by a dash-boad cluster controller, which gets CAN/OBD-II info from the ECM. Like a number of Intrigues/etc, my temperature gauge has a tendency to "flake out". It does it maybe once a month in warmer temperatures. I keep a blue-tooth OBD-II dongle in the car, and I have the paid version($5) of Torque Pro (OBD 2 & Car) on my phone. I also keep a cheap/small OBD-II scanner that shows real-time data. That's faster and quicker, for me to verify that the engine temperature is fine. For what it's worth, the engine temperature can't change "very quickly". So, if you see the needle "moving" or jumping around, it's likely not the actual engine temperature. Fwiw, below is an old screen capture of live data, using the dongle, and app running on my old tablet: Good Luck! Edited February 15, 2020 by Cutlass350 Quote Link to comment Share on other sites More sharing options...
55trucker Posted February 15, 2020 Report Share Posted February 15, 2020 (edited) 8 hours ago, Psych0matt said: Should be on the side of the radiator, drivers side. It has a clip and a plug. ???????? The gauge sensor is mounted into the forward cylinder head, it's behind the engine lifting eye casting, to get it out one needs to remove the exhaust crossover/slacken it off to drop it, then the lifting eye, now one can get at it to screw it out. The rad sensor is the coolant low level sensor. Edited February 15, 2020 by 55trucker Quote Link to comment Share on other sites More sharing options...
Psych0matt Posted February 15, 2020 Report Share Posted February 15, 2020 Ahh my bad, it’s been a few years since I’ve Messed with the sensors Quote Link to comment Share on other sites More sharing options...
crunkGP96 Posted February 15, 2020 Author Report Share Posted February 15, 2020 It’s a 95 so it’s obd 1.5. Wish it was a 96 for these reasons but for a long time I no longer had to pass emissions tests because of it lol I can actually get antique plates for it this year. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
crunkGP96 Posted February 15, 2020 Author Report Share Posted February 15, 2020 ???????? The gauge sensor is mounted into the forward cylinder head, it's behind the engine lifting eye casting, to get it out one needs to remove the exhaust crossover/slacken it off to drop it, then the lifting eye, now one can get at it to screw it out. The rad sensor is the coolant low level sensor.I figured it was somewhere else. Thanks! Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
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