help -- overheating or busted sensor?

93GTDIN · 08-30-2002, 06:02 PM

an hour ago on my way to the bank I looked down at my temperature gauge as I often do, and It was at the top right below the red mark. I pulled over and saw no steam under the hood, and the engine didn't seem overly hot (i dont know if it even would if it is overheating or not). I squeezed the hose going to the thermostat housing and it was full. Radiator has water in it. I let the car cool down and I drive it home (about a mile). The car seems to run fine, and the gauge once again goes to the top. Once it gets there, it fluctuated one full notch (35 degrees) up and down in the span of about 10 seconds, probably less. It did this twice, and overall was erratic. The car heated almoast all the way up before I was out of the parkinglot at the bank (small parking lot)

So as far as I know, it was impossible for water to heat, cool, heat, and cool so quickly, especially in a motor.

My initial thought were that my thermostat was stuck closed... but now I think I might have a busted gauge. What do you guys think?

Thanks a heap
dino

bigblockcoupe · 08-30-2002, 06:07 PM

sounds like the sender is bad to check it get you one of those long thermometers like you use for a/c and pull the sender and stick the thermometer in the hole to see what the real temp is be careful to remove the sender slowly if the motor is hot just in case the temp really is up there.

93GTDIN · 08-30-2002, 07:42 PM

I went ahead and changed the temperature sender, and no water was in the intake. Of course the car had time to cool down. At any rate, that was not the problem. I changed it, and same thing. So I parked it and checked the thermostat hose and the thermostat had not opened b/c there was no water in the hose. Now I assume if the temp of the water had gotten to 250ish as the gauge read, the thermostat would have opened. I'm confused... could my water pump be busted? how can I check that?

bigblockcoupe · 08-30-2002, 08:26 PM

well either your gauge took a dump or you have some other problem if you are absolutely sure the cooling system is full ie you pulled one of the heater core hoses off at the firewall and filled it until coolant was coming out of it (this gets all the air out of the system) it could be a thermostat sticking. but first feel the top radiator hose when the thermostat opens it will get hot then check the temp like i said in my first post. my gauge recently went out and was jumping around alot it would alternate 10-15 degrees rapidly then it started reading low all the time it would hardly get on the bottom line so i checked it by pulling out the sender after i drove home from work the gauge wasn't even showing 130 degrees but my thermometer said 190 degrees so i knew the gauge took a crap i had already tried the sender now i have a manual gauge.

08-30-2002, 06:02 PM	#1
93GTDIN Registered Member Join Date: Jan 2001 Location: Live music capital of the world, TX Posts: 324	help -- overheating or busted sensor? an hour ago on my way to the bank I looked down at my temperature gauge as I often do, and It was at the top right below the red mark. I pulled over and saw no steam under the hood, and the engine didn't seem overly hot (i dont know if it even would if it is overheating or not). I squeezed the hose going to the thermostat housing and it was full. Radiator has water in it. I let the car cool down and I drive it home (about a mile). The car seems to run fine, and the gauge once again goes to the top. Once it gets there, it fluctuated one full notch (35 degrees) up and down in the span of about 10 seconds, probably less. It did this twice, and overall was erratic. The car heated almoast all the way up before I was out of the parkinglot at the bank (small parking lot) So as far as I know, it was impossible for water to heat, cool, heat, and cool so quickly, especially in a motor. My initial thought were that my thermostat was stuck closed... but now I think I might have a busted gauge. What do you guys think? Thanks a heap dino __________________ 96 Cobra - a bit too stock. 14.0 @ 101

08-30-2002, 07:42 PM	#3
93GTDIN Registered Member Join Date: Jan 2001 Location: Live music capital of the world, TX Posts: 324	I went ahead and changed the temperature sender, and no water was in the intake. Of course the car had time to cool down. At any rate, that was not the problem. I changed it, and same thing. So I parked it and checked the thermostat hose and the thermostat had not opened b/c there was no water in the hose. Now I assume if the temp of the water had gotten to 250ish as the gauge read, the thermostat would have opened. I'm confused... could my water pump be busted? how can I check that? __________________ 96 Cobra - a bit too stock. 14.0 @ 101

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08-30-2002, 06:07 PM	#2
bigblockcoupe Registered Member Join Date: Aug 2002 Location: broken arrow Posts: 212	sounds like the sender is bad to check it get you one of those long thermometers like you use for a/c and pull the sender and stick the thermometer in the hole to see what the real temp is be careful to remove the sender slowly if the motor is hot just in case the temp really is up there.

08-30-2002, 08:26 PM	#4
bigblockcoupe Registered Member Join Date: Aug 2002 Location: broken arrow Posts: 212	well either your gauge took a dump or you have some other problem if you are absolutely sure the cooling system is full ie you pulled one of the heater core hoses off at the firewall and filled it until coolant was coming out of it (this gets all the air out of the system) it could be a thermostat sticking. but first feel the top radiator hose when the thermostat opens it will get hot then check the temp like i said in my first post. my gauge recently went out and was jumping around alot it would alternate 10-15 degrees rapidly then it started reading low all the time it would hardly get on the bottom line so i checked it by pulling out the sender after i drove home from work the gauge wasn't even showing 130 degrees but my thermometer said 190 degrees so i knew the gauge took a crap i had already tried the sender now i have a manual gauge.