Saturn SL1 overheating

Tiny
WINGNUTTINTX
  • MEMBER
  • 2002 SATURN SL1
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 300,000 MILES
My Saturn sl1 2002 is overheating while in stop and go traffic. I have replaced the radiator and the thermostat last fall. I have also replaced the water pump and belt in Feb. But after a long trip to Texas, the car overheated in stop and go traffic. When I stopped the car, I looked under the hood and the cooling fan did not come on, and the coolant was leaking out of the cap. My question is, should I replace the heating coolant sensor And the fan motor or just the cooling sensor and see where I am at? Also, if I was leaking out of the cap, I would think that it also needs to be replaced and would that make any difference to being the cause to it overheating?
Monday, February 15th, 2016 AT 9:25 AM

7 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 34,194 POSTS
We don't ever replace parts on customers' cars by guessing. The defect must be diagnosed, then only the bad part is replaced. If you have a radiator fan relay, bypass it to see if the fan motor turns on. Most commonly it will not. Typically the motor gets tight which makes it draw higher-than-normal current and blow a fuse or fuse link wire. If you want to get that involved on your own, list which engine and transmission you have, and have a voltmeter or test light handy, then I'll dig up a wiring diagram to figure out where to start. Quite often the majority of the measurements can be taken at the relay socket.
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Monday, February 15th, 2016 AT 10:16 AM
Tiny
WINGNUTTINTX
  • MEMBER
  • 4 POSTS
1.9 liter and have no idea which tranny is in this 2001. I thought they were the same after a certain year. I do not want to get that involved. My tester and that stuff is still in Minnesota and I only have basic tools here while visiting in Texas. With the sensors under 15 dollars and the fan motor at 35, I will just replace them. They are 15 years old and I have never replaced any of that stuff.
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Monday, February 15th, 2016 AT 6:18 PM
Tiny
CARADIODOC
  • MECHANIC
  • 34,194 POSTS
I'm in the middle of Wisconsin. Friend just moved his sister back up here from Austin, TX.

By "tranny", I mean manual or automatic. Need to know that if I have to look for a wiring diagram.
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Monday, February 15th, 2016 AT 6:45 PM
Tiny
WINGNUTTINTX
  • MEMBER
  • 4 POSTS
Sorry, automatic
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Monday, February 15th, 2016 AT 8:55 PM
Tiny
CARADIODOC
  • MECHANIC
  • 34,194 POSTS
There's two common was a radiator fan motor will fail. One is worn brushes. For that, a new motor is all that's needed.

The second is the bearings get tight. A slow-moving motor draws excessive current and that will blow a fuse or burn open a fuse link wire. For that you need a new motor AND a new fuse device.

The best approach is to use a scanner to activate the fan motor, then take two voltage readings on its connector. If there's no voltage getting to the motor, a new motor won't run either. Then we have to check for a relay and see if that is clicking on, and a fuse device and see if that is good.
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Wednesday, February 17th, 2016 AT 12:26 PM
Tiny
WINGNUTTINTX
  • MEMBER
  • 4 POSTS
Thanks caradiaodoc.

I ended up replacing the fan motor (it wasn't working) and the engine coolant sensor before I left Texas. I drove it the 1000 miles to Minnesota and had no issues. I even let it run for a bit at rest areas, while I used the bathroom and it didn't overheat. I do have a tiny leak somewhere but that is going to involve a lot of looking and investigating on my part. Thanks for your help.
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Wednesday, March 2nd, 2016 AT 5:49 AM
Tiny
CARADIODOC
  • MECHANIC
  • 34,194 POSTS
Dandy. Happy to hear it's solved.

For a slow leak, consider adding a small bottle of dark purple dye to the coolant, then search a day later with a black light. The dye will show up as a bright yellow stain that you can follow back to the source. Auto parts stores will have the dye to match the liquid being tested, and those that rent or borrow tools should have a black light.
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+1
Wednesday, March 2nd, 2016 AT 7:19 PM

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