Cooling system problem

looneyluden · 10-20-2000, 08:10 PM

Hello,
I'm new to the board and have a problem. I have a '97 SCII with 44k on it. The Coolant level low and coolant light recently started flashing. I added some coolant as this had fixed the problem twice before in the last year or so. The lights don't flash anymore, but now they come on and stay on steady. And whats even weirder is the temperature gauge has since started to peg out in the red. The engine can't be overheated can it? It's got full coolant, and the coolant was flushed and replaced about 10 months ago. Even if the car has sat for hours or over-night, and I even just turn the key without starting the engine, the temp-needle will start jumping around. Every few seconds it moves up or down. This with a completely cold engine(I live in alaska)! One more symptom is that when I turn the engine off, the engine fan stays on. Also, sometimes if i just go out and turn the key without starting the engine, then turn the key all the way off again, the fan will come on.

I am not informed at all about cars. But from this info, it seems to me my car is thinking it is overheated. (coolant lights on,temp gauge in the red,fan running) But it can't be overheated because the coolant level is good and all of these symptoms happen with even a cold engine. Any ideas?

MrBigglesworth · 10-21-2000, 01:43 PM

It sounds like you may have a bad coolant temperature sensor. If the sensor is sending the computer a bad signal, the computer may think that your car is overheating when it really is ok. If this is the case the computer would tell the fan to kick on even if the car isnt running along with warning lights and the gauge in the red zone.

looneyluden · 10-21-2000, 02:09 PM

Thanks for the help. I went out this morning to see what it would do and it immediately showed all the signs of overheating again. Funny thing is its 20 degrees out there. But more bad news, my battery is too weak to start the car at all now. I new I would need a new one this winter because last year once or twice i needed to get a jump on a cold morning. I guess the fan running everytime I turned the engine off the past two days didn't help the battery much.

Once this is all done, I'm getting one of those block or battery heaters. Is the coolant temp sens. easy to change? Is it cheap? I'm going to have friend run me by saturn to ask them about it.

ssicarman · 10-21-2000, 02:36 PM

Sounds like you could have an overheating problem due to a bad temperature sensor. Your symptoms are very typical of a bad temperature sensor. But with your last posting I would suggest that you also get your charging system checked out as well as a low voltage situation can also cause some very strange things to happen to the cars electrical system.

looneyluden · 10-21-2000, 06:25 PM

Hey I think there is some other problems too. I went and got a new battery(man whats up with that battery heatshield, that is not fun to take off when it is cold outside!) When I went to start it, it would try to start, but wouldn't kick in. Finally after many tries it did. It would then idle ok. Then when I would give it gas, it would rev up, but when I let off the gas it would sputter out and the engine would stop. Finally after warming up some, it would let me rev it without it stalling out when i let off.

I talked to a few people today. Someone I met today who rebuilds saturns suggested that maybe i had an air-lock somewhere in the coolant system. I thought this made sense because the whole "overheat" problem occured after i had added some coolant when it got low. He said an airlock can cause weird things like that. So I followed his advice and jacked the front of the car up, then removed the resevior cap, and let it run for a few minutes. He said if there was an airlock, that should bleed it out. No such luck though. I may try it again later.

sattech · 10-21-2000, 08:16 PM

A bad coolant sensor will give you the same symptoms as you described. The sensor is located at the back of the cylinder head. Remove the 2 wire conn. and replace with a 13mm deep socket. Make sure the engine is cold and remove then resecure the coolant res. cap to remove any pressure. reinstalling the cap helps keep the coolant in

looneyluden · 10-25-2000, 07:41 PM

You guys were right. It was the coolant temp sensor. Also the connector was corroded. I let Saturn do it. Glad to have my Saturn back to normal again. They even gave the car a bath and left me some mints on the dash!

10-20-2000, 08:10 PM	#1
looneyluden New Member Join Date: Oct 2000 Posts: 8	Cooling system problem Hello, I'm new to the board and have a problem. I have a '97 SCII with 44k on it. The Coolant level low and coolant light recently started flashing. I added some coolant as this had fixed the problem twice before in the last year or so. The lights don't flash anymore, but now they come on and stay on steady. And whats even weirder is the temperature gauge has since started to peg out in the red. The engine can't be overheated can it? It's got full coolant, and the coolant was flushed and replaced about 10 months ago. Even if the car has sat for hours or over-night, and I even just turn the key without starting the engine, the temp-needle will start jumping around. Every few seconds it moves up or down. This with a completely cold engine(I live in alaska)! One more symptom is that when I turn the engine off, the engine fan stays on. Also, sometimes if i just go out and turn the key without starting the engine, then turn the key all the way off again, the fan will come on. I am not informed at all about cars. But from this info, it seems to me my car is thinking it is overheated. (coolant lights on,temp gauge in the red,fan running) But it can't be overheated because the coolant level is good and all of these symptoms happen with even a cold engine. Any ideas?

10-21-2000, 06:25 PM	#5
looneyluden New Member Join Date: Oct 2000 Posts: 8	Cooling system problem(UPDATE) Hey I think there is some other problems too. I went and got a new battery(man whats up with that battery heatshield, that is not fun to take off when it is cold outside!) When I went to start it, it would try to start, but wouldn't kick in. Finally after many tries it did. It would then idle ok. Then when I would give it gas, it would rev up, but when I let off the gas it would sputter out and the engine would stop. Finally after warming up some, it would let me rev it without it stalling out when i let off. I talked to a few people today. Someone I met today who rebuilds saturns suggested that maybe i had an air-lock somewhere in the coolant system. I thought this made sense because the whole "overheat" problem occured after i had added some coolant when it got low. He said an airlock can cause weird things like that. So I followed his advice and jacked the front of the car up, then removed the resevior cap, and let it run for a few minutes. He said if there was an airlock, that should bleed it out. No such luck though. I may try it again later.

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10-21-2000, 01:43 PM	#2
MrBigglesworth Member Join Date: Jun 2000 Posts: 73	It sounds like you may have a bad coolant temperature sensor. If the sensor is sending the computer a bad signal, the computer may think that your car is overheating when it really is ok. If this is the case the computer would tell the fan to kick on even if the car isnt running along with warning lights and the gauge in the red zone.

10-21-2000, 02:09 PM	#3
looneyluden New Member Join Date: Oct 2000 Posts: 8	Thanks for the help. I went out this morning to see what it would do and it immediately showed all the signs of overheating again. Funny thing is its 20 degrees out there. But more bad news, my battery is too weak to start the car at all now. I new I would need a new one this winter because last year once or twice i needed to get a jump on a cold morning. I guess the fan running everytime I turned the engine off the past two days didn't help the battery much. Once this is all done, I'm getting one of those block or battery heaters. Is the coolant temp sens. easy to change? Is it cheap? I'm going to have friend run me by saturn to ask them about it.

10-21-2000, 02:36 PM	#4
ssicarman Super Member Join Date: Oct 2000 Location: Western Canada Posts: 10,470 ssicarman's Photos	Sounds like you could have an overheating problem due to a bad temperature sensor. Your symptoms are very typical of a bad temperature sensor. But with your last posting I would suggest that you also get your charging system checked out as well as a low voltage situation can also cause some very strange things to happen to the cars electrical system.

10-21-2000, 08:16 PM	#6
sattech Senior Member Join Date: Feb 2000 Location: Saturn of Norwood, Ma Posts: 1,466	A bad coolant sensor will give you the same symptoms as you described. The sensor is located at the back of the cylinder head. Remove the 2 wire conn. and replace with a 13mm deep socket. Make sure the engine is cold and remove then resecure the coolant res. cap to remove any pressure. reinstalling the cap helps keep the coolant in

10-25-2000, 07:41 PM	#7
looneyluden New Member Join Date: Oct 2000 Posts: 8	You guys were right. It was the coolant temp sensor. Also the connector was corroded. I let Saturn do it. Glad to have my Saturn back to normal again. They even gave the car a bath and left me some mints on the dash!

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