Engine coolant light is on

Tiny
ROBIN WILEY
  • MEMBER
  • 2001 SATURN SL1
  • 1.9L
  • 4 CYL
  • MANUAL
  • 225,000 MILES
My engine coolant light is staying on. The reservoir is full. What can some of the causes be?
Saturday, October 22nd, 2016 AT 2:55 PM

8 Replies

Tiny
AL514
  • MECHANIC
  • 4,105 POSTS
The switch for the coolant level is actually at the bottom of the coolant reservoir. So you may want to take a look at the bottom of the tank and see if the harness plug either fell off or if there is a wiring problem down there. The pink wire at the plug for the level switch is the power wire and the yellow/black wire is the wire that signals the ECM that the switch is closed and the reservoir is full. Here is a wiring diagram to help to identify the harness plug down there. Should be very easy to find.
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Saturday, October 22nd, 2016 AT 5:01 PM
Tiny
AL514
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The car is not overheating correct?
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-1
Saturday, October 22nd, 2016 AT 5:05 PM
Tiny
MAXIMILIAM
  • ADMIN
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It has a brand new water pump, radiator and thermostat. I put water in it just to make sure I have no leaks. I put water directly into radiator and it comes back out. I took it for test drive I came back and no water in radiator but reservoir is full. Can I get some kind of idea on what to do now? Also, it has no heat now. It did.

Robin Wiley
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Monday, October 24th, 2016 AT 10:46 AM
Tiny
AL514
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There is probably air pockets in the radiator and engine block, run the engine with the radiator cap off until the thermostat opens and you will see the coolant in the radiator drop, the add more until it is full. You have to get all the air out, there also may be a bleeder near the thermostat housing that you can unscrew to allow air to escape. The coolant sensor will not read air only fluid, I am not sure which light you have on, the level sensor or the actual coolant temperature sensor.
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Monday, October 24th, 2016 AT 11:07 AM
Tiny
ROBIN WILEY
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  • 3 POSTS
Check engine light and "HOT" light. I have had a problem with overheating. The radiator got a hole in it shortly after the water pump went. Replaced both at same time. Still overheating. So I replaced thermostat. Now I can't keep water in reservoir it comes back at me. Now I have no heat. Do I need to replace heater core? I do have a bleeder.
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Tuesday, October 25th, 2016 AT 5:41 PM
Tiny
ROBIN WILEY
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  • 3 POSTS
Not reservoir- radiator. Still overheating
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Tuesday, October 25th, 2016 AT 5:43 PM
Tiny
AL514
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You probably don't have any heat because there is air in the system, how long has the car been over heating? Before you did the water pump also?
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Tuesday, October 25th, 2016 AT 6:21 PM
Tiny
AL514
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And if you also have the check engine light on, there is a diagnostic trouble code stored in the computer, this code should be read by a scantool, You can either buy one, they have very cheap code readers you can buy now or most autoparts stores will read the code for free ( because they think they can sell you replacement parts), I don't think you need a heatercore at this point. You need to bleed the air out first. If you had heat before you changed over those parts it should be fine.
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Wednesday, October 26th, 2016 AT 3:33 AM

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