Mechanics

COOLING SYSTEM HELP!

1996 Saturn SL1 • 120,000 miles

Im totally lost on this one. I have a 96 Saturn SL1 1.9 Vin 8, the surge tank will "over flow" before it hits "normal" operating temp. For fun I wanted to see if the radiator fan turns on at operating temp, but it doesnt and the needle keeps rising. Because it is a GM vehicle, I figured that it could need to go up alittle more from middle to turn on. Again, no fan. This point I swapped thermostat and waterpump, swapped a surge tank cap for a dealer one, checked radiator hoses, relays and fuses, checked PSI rating, heater core hoses, ECT Sensor. No leaks, good psi (BTW 18psi), all hoses "luke warm" before the car decides to boil over at me, and no electrical short. Now I can leave the ECT unplugged to get my fan to run constant and my gauge in the dash not to work, but that would suck in the winter.

Plz help, I'm totally lost!
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Phate1606
September 16, 2011.




See Pic for circuit for cooling fan, check the fuse, relay and temp sensor.


Mhpautos
Sep 16, 2011.
Just to add to this one you replaced the coolant temp sensor?Did you inspect the connector to make sure the terminals arent corroded?If they are green or blue you will have to replace the connector. Also what color was the part that the connector goes on the new sensor?The coolant does look like a thick choclate milk shake does it?You also replaced the thermostat?Have you done a chemical test to make sure you dont have a blown head gasket or cracked head?Also how does the oil look?You cant leave the coolant temp sensor unplugged summe or winter it also tells the computer the what the engine temp is so it can adjust the fuel ratio injector pulse etc.


Saturntech9
Sep 16, 2011.
Thank you for the wiring diagram!

The coolant isnt chocolate, and the oil isnt milkshaked. Thermostat has been changed, well after 2 surge tank caps, the system stopped boiling, but the fan still doesnt kick on, and no heat. I used an air-lift system to fill the coolant. Maybe a clogged heater-core since I had no hot input or output hose? I did notice a drip from the radiator so that will be changed over the weekend.
Thank you for the responses.


Tiny
Phate1606
Sep 17, 2011.
Even with a clogged heater core it shouldnt boil over on that car. So how high does the gauge go with the fan not coming on?Also what color is the connector on the coolant temp sensor you replaced where the coolant temp sensor connector goes on?Also did you inspect the coolant temp sensor for being corroded?So its not boiling over anymore?Are both the upper and lower radiator hoses getting really hot?


Saturntech9
Sep 17, 2011.
The color connecter is black (its the only connector around), the upper and lower radiator hoses get hot, there was a blockage in the heater core. The new ECT has no corroded pins or any corrosion in the connector. BEFORE the new cap it wouldnt even hit middle line and the coolant would boil, AFTER the new cap the coolant doesnt boil out, but it rises almost to the 3rd line before I shut it off to let it cool. I'm out of answers, I also checked the wiring and made sure of no melted wires, crossed wires, and proper voltage.
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Tiny
Phate1606
Sep 23, 2011.
I was asking what color the coolant temp sensor was where the connector goes on?Also the connector on the engine harness that goes to the coolant temp sensor those terminals are silver?Also its not boiling over anymore?If memory serves right the fan doesnt come on till 3/4 on the temp gauge. Do you have a temp gun?


Saturntech9
Sep 23, 2011.
Oh, I'm sorry. Totally mis-read the questions. The color of the old sensor was green and coroded, the connector pins are silver. Sorry I was thinking you wanted the color of the actual connector and sensor. So. It actually waits that long for a GM vehicle to get to the third line before the fan kicks on? I was figured middle line was the normal temp.


Tiny
Phate1606
Sep 23, 2011.
Yes I do have a temp gun.


Tiny
Phate1606
Sep 23, 2011.
The later S model saturns came on at just over half way I think they started doing that from 1998 till 2002 when they stopped making the S model and the Ion replaced the S model in 2003. If the fan comes on when you unplug the sensor we know the computer relay wires fuse fan motor etc are good. That only leaves the sensor which was replaced the connector and the wires from the computer to the sensor. Also what color is the plastic on the new coolant temp sensor that sticks out of the head?


Saturntech9
Sep 23, 2011.
Alright right where the metal part on the head where the upper radiator hose attaches thats where your going to check the coolant temp. Let the car idle and see if the radiator fan kicks on between 222-226 degrees. Let me know what you find.


Saturntech9
Sep 23, 2011.

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