2001 Saturn SC1 Thermostat Issues

2001 Saturn SC1 Thermostat Issues

Recently I was having problems with my 2001 Saturn SC1 series over heating from a faulty thermostat. The car ran fine most of the time, but driving in stop/start traffic in the city would cause the coolant to start steaming out the side overflow reservoir tank. After a day or two, the coolant would be gone and the vehicle would start over heating. This also seemed to happen on really hot days when the outside temperature was more than 90 degrees farenheit.

Stant 10238 Radiator Cap - 16 PSII had taken this auto to Goodyear and Mr. Tire without much luck. Mr. Tire put on a new radiator cap and declared the problem was solved. What a joke! Three days later it was back to adding coolant to the reservoir tank again. So I took the Saturn to a local mechanic. He measured the temperature of the coolant throughout the cooling system with an infrared temp detecting gun.


He told me that the temperature on the outflow side of the engine was much greater than the temperature on the inflow side of the engine. The coolant outflow side is on the same side as the reservoir tank, was too hot and thus the coolant was steaming out (even with a new tight fitting radiator cap). He was convinced the car needed a new thermostat and replaced it.

Stant 45359 SuperStat Thermostat - 195 Degrees FahrenheitAfter the thermostat installation, he determined the coolant temperature on both the inflow and outflow sides of the engine were nearly the same. I was a little concerned because the temperature guauge on the dashboard was reading hiher than normal (or what I was was accustomed to seeing).

Normally, the temperature reading would always sit around the 1/4 mark. A little research showed that this corresponds to a temperature of 185 degrees farenheit. But it occured to me that the reading was always stuck there because I was driving around with a thermostat that was not working.

The temperature sensor that relays the temp reading to the gauge on the dashboard sits on the engine inflow side of the cooling system. The mechanic had mentioned that side was cooler before replacing the thermostat. A little more research revealed that there are two types of thermostats that can be used for the 2001 Saturn SC1 series. One thermostat is rated at 185 degrees and the other is rated aas a 195 degree thermostat.

Zerex ZXGO51 G-05 Antifreeze - GallonThe 195 degree thermostat opens at the higher temperature. So essentially, the coolant temperature gets 10 degrees hotter before the thermostat opens and allows the coolant to start circulating. At first, this didn’t sound like a good idea, but I looked into it further since the car temperature gauge was now running at the 3/8 th’s mark instead of the 1/4 mark I had grown accustomed to.

Several other sites had mentioned that this was a good thing and that the Saturn SC1 should have been sold with the 195 degree thermostat installed in the first place. The reason being that the temperature difference in allowing the engine to run a little hotter improved gas mileage. They also mentioned that the heater output will be warmer in the winter. We shall see about that when winter gets here.

And to my surprise, they were right. Over the years I seemed to average about 34 miles per gallon for highway driving. This is pretty good and higher than what the vehicle MPG rating is suppose to be in the first place. But other things do factor into gas mileage such as proper tire inflation pressure, oil changes, etc.

Now that the coolant temperature is higher with the new 195 degree thermostat, I’m averaging 37 miles per gallon on the highway! This was a lot higher than expected and above the normal rating of 36 MPG as rated by the EPA for fuel economy. So basically, I was never getting the EPA rated miles per gallon for the last 10+ years!

Now with the new thermostat, I’m finally getting the gas mileage and fuel economy I was suppose to getting all along. This is very important when you consider the last time I looked at gasoline fuel prices, they were back up around the $3.80 per gallon range again.

So the lesson learned is that if you can install the 195 degree thermostat in the 2001 Saturn SC1, you should definitely do it! It may take a little time getting use to seeing the temperature gauge read at the 3/8th’s mark instead of the 1/4 mark, but you’ll get comfortable and use to it after several days or weeks. And you’ll definitely gets use to the improved gas mileage! 🙂

2001 Saturn SC1 Thermostat Issues
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One Response to 2001 Saturn SC1 Thermostat Issues

  1. Beavis says:

    I drive a tractor. I’m pretty cool … hm hm. 🙂

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