97 saturn overheating

i have replaced the fan motor,ects,the ects connector, fan relay,and i get the same outcome.i have my 5 volts at the ects connector from pcm,fan will not come on.the fan comes on only if i remove ects connector from sensor.the a/c doesnt kick fan on because i believe it has no charge in system.i also have no trouble codes.when my temp gauge gets to a little after middle it starts to overheat and water spues from res.this is a 1997 sc2 with the only one ects.the crazy thing is when it overheats my temp gauge is not in the red nor does the flashing warning lights come on.any ideas anybody?thx

I'm thinking bad reservoir cap. Not allowing the proper pressure to build up before it vents.

should the fan come on when the ects sensor connector is taken off the sensor?because mine does and another tech said that it shouldnt come on and he thought there was a short somewhere giving the pcm the full 5 volts.but there is no short going back to pcm on the return.i even replace the connector to make sure there wasnt a short in connector.ive replace sensor twice to make sure i didnt get a bad one out of box and i tested in hot water and when there cool and they are fine.my new fan motor has a good ground and she starts up fine when i jump it out .relay is good its all good.and no pcm codes.aaaaaaaahhhhhhhhhhhhhhhhhhhhhhh!!!!!!!!!!!!! !!!!!!!!
could it be possible that the pcm has a memory loss and it wont show up on a scan tool?

Let's fix one problem at a time. Did you replace the reservoir cap? Your car is not overheating, it's not allowing proper cooling system pressure to build up before it bleeds it off. The reservoir cap is the pressure regulator. It's defective.

ok,i been working on this car and testing stuff and didnt relize that i just had water in it.pure water will never get any higher than 212 degrees no matter how much heat you put to it,it will only boil faster.so i drained block and rad and put coolant in a 50/50 mix.this coolant should boil at 265 in normal conditons,or 225 if its not coming to pressure like your talking about.ive been told that my fan should come on after 220 degrees.not sure how much more but tank did steam and vent yesterday and fan didnt come on,but i got a new cap to try again today.im guessing that the coolant was at least 225 yesterday and the fan still didnt come on.

Water boils at 212F at sea level. If the water is under pressure, the boiling point rises above that. Adding coolant further increases the boiling point but only if the system is under pressure. No pressure, lower boiling point.

thats what im saying,water should boil at 250 degrees in a 15psi system.your probably right about the cap and my water was boiling at 212 or somewhere around there,with the new cap i should get my pressure with the correct boiling point.where do you think my gauge reading should be for the fan to kick on?when i put coolant in ,the gauge did go to almost 3/4 of the way before it started to steam but no coolant overflow this time and the fan still wouldnt come on ,this seams a little high for me and i dont want to burn it up.

around 3/4 is when it turns on but if the a/c does not turn it on then you have a problem.

your the man,it was the cap,thx again

your the man,it was the cap,thx again


Cool, glad I could help.

I just bought a 93 SC2. It was having the issue where it wouldn't warm up and then was all over the map temp wise. I replaced the thermostat, both ects sensors, the connector for the 2 wire one (the 1 wire replacement was an accident tapped the connector reaching in and it decided to crack off on me... I swear those things look like land mines to me when I look under a saturn hood now). I also ended up having to replace the radiator. After all that work a crack showed up in the radiator.

Anyways I thought this solved everything. The car heats up normally seems better under control UNLESS I am idling. The temp gauge likes to go up to the 3/4 mark still... Is this normal. I usually freak out and turn on the A/C and consequently the fan because I don't want to find out what happens the hard way. But is this normal for a Saturn to just let the engine get this hot before the fan turns on? Obviously the fan works if the A/C trick fixes it. It seems like I got everything else that would cause this phenomenon....

Yes.. it is normal for the temperature gauge to go up to the red before the ects sends signal to turn on the fan. It is hard to get familiar with this however as you know that the temperature gauge and the coolant sensor have no attachment like in the '97.. The in car gauge is more of an indicator than an accurate temperature gauge.

Just make sure the fan comes on by testing it. The fan should come on as it approaches the red on the temperature gauge.

my fan comes on to almost 3/4,then cools it to about center or more.if mine goes to the red it would be overheating.

I have a 94 SL1 and I have the same problem. When I am idled, the temp gauge goes up and I freak out and turn on the AC. I'm afraid to let it get to red. But this is 100% normal? That would be great to hear because a Saturn dealership said the whole cooling system or something needed to be replaced.

It is normal for the gauge to indicate above average "up to" the red.

Your 1994 car is getting up there in age. You must make sure the engine coolant temperature sensor has been replaced with the brass tipped one available for about $15 and easy to change with a 13mm deep 6 point socket. As the car gets older, the radiator and thermostat do not operate as efficiently. It is important that they do. These parts are common replacements within the service life of the car like water pump, coolant change, hoses and belts

The good thing about the S series car is it is very easy to work on and parts are generally cheap. The bad thing about the car is if you do not repair or maintain your car and you "let it go", one major repair need costs you more than the value of the car. Hence, the weekend DIYer with minimal tools can have an efficient and decent looking car for a long time.

I have no idea whats been changed in the car. It was my mom's and she gave it to me when I left for college and she has no idea what was done to it when she took it in for work. Also, I have taken it to a shop to see if they could figure out why it looked like it was overheating, and they said there was no record on the ECU of the car ever overheating. Then they said I needed a new cooling fan. I'm a poor, confused college student who knows nothing about this stuff. Is there some way I can look for the sensor you mentioned to see if it is brass tipped? And put things in very simple terms for I am a girl.

Here is the info on the engine coolant temperature sensor:

http://www.saturnfans.com/forums/showthread.php?t=37884

Buy the cooling fan motor. It is also easy to install.

http://autozone.com/selectedZip,12831/initialAction,partProductDetail/initialpartType,00150/initialR,APP275515/initialvehicleId,1968401/shopping/selectZip.htm