low coolant light stays on...

[Edmond]

but the coolant isn't low. The radiator is filled all the way up and the overfill tank is more than half full. Any ideas on why this is happening?

 

[Magmotor]

Mine did the same thing but was intermintent. I replaced the sensor and all was fixed. If that doesn't solve the problem then I have a step by step system check for the "Low Level Light Stays On" but it's too big to post on here. PM me if you think you need it.

 

[Ken]

I seems we don't have that information in our Knowledgebase yet, but here are some bulletins for the 1987 and 1988 C4s. You get the idea.

• Service Bulletin Number: 88-43-6BREI
  Bulletin Sequence Number: 130
  Date of Bulletin: 8809
  NHTSA Item Number: SB002812
  Make: CHEVROLET
  Model: CORVETTE
  Year: 1987
  Component: ENGINE COOLING SYSTEM
  Summary: LOW COOLANT WARNING LIGHT CAUSED BY AIR TRAPPED IN COOLING SYSTEM-COOLANT LIGHT MODULE SHOULD CHECKED FOR PROPER FUNCTION-IF LIGHT DOES NOT GO OUT, CHECK FOR BROKEN OR LOOSE WIRES-NECESSARY TO REPLACE LOW COOLANT SENSOR PROBE AND HOSE CLAMPS ON COOLANT RECOVERY HOSE-P/N 10054615 LOW COOLANT SENSOR PROBE AND 22527587 HOSE CLAMP-ALL 1986/1988 CHEVROLET CORVETTE MODELS TLH

• Service Bulletin Number: 87-11
  Bulletin Sequence Number: 145
  Date of Bulletin: 8610
  NHTSA Item Number: 87315
  Make: CHEVROLET
  Model: CORVETTE
  Year: 1987
  Component: ENGINE COOLING SYSTEM:OTHER PARTS
  Summary: LOW COOLANT WARNING LIGHT-LIGHT COMING ON-INSUFFICIENT CLAMPING OF RECOVERY HOSE BETWEEN RADIATOR AND RECOVERY BOTTLE-INSTALL NEW LOW COOLANT SENSOR PROBE-PART NUMBER 10054615 SENSOR PROBE, 22527587 CLAMP-ALL 1986-1987 CHEVROLET CORVETTE MODELS

• Service Bulletin Number: 88-43
  Bulletin Sequence Number: 190
  Date of Bulletin: 8709
  NHTSA Item Number: 96859
  Make: CHEVROLET
  Model: CORVETTE
  Year: 1987
  Component: ENGINE COOLING SYSTEM:OTHER PARTS
  Summary: LOW COOLANT WARNING LIGHT-ADDITIONAL PROCEDURES REGARDING THERMAL CYCLING PROVIDED-CHECK FOR BROKEN OR LOOSE WIRES OR FAULTY LOW COOLANT MODULE-ALL 1986 TO 1988 CHEVROLET CORVETTES MODELS

• Service Bulletin Number: 88-43
  Bulletin Sequence Number: 190
  Date of Bulletin: 8709
  NHTSA Item Number: 96859
  Make: CHEVROLET
  Model: CORVETTE
  Year: 1988
  Component: ENGINE COOLING SYSTEM:OTHER PARTS
  Summary: LOW COOLANT WARNING LIGHT-ADDITIONAL PROCEDURES REGARDING THERMAL CYCLING PROVIDED-CHECK FOR BROKEN OR LOOSE WIRES OR FAULTY LOW COOLANT MODULE-ALL 1986 TO 1988 CHEVROLET CORVETTE MODELS

• Service Bulletin Number: 88-43-6BREI
  Bulletin Sequence Number: 130
  Date of Bulletin: 8809
  NHTSA Item Number: SB002812
  Make: CHEVROLET
  Model: CORVETTE
  Year: 1988
  Component: ENGINE COOLING SYSTEM
  Summary:[/b] LOW COOLANT WARNING LIGHT CAUSED BY AIR TRAPPED IN COOLING SYSTEM-COOLANT LIGHT MODULE SHOULD CHECKED FOR PROPER FUNCTION-IF LIGHT DOES NOT GO OUT, CHECK FOR BROKEN OR LOOSE WIRES-NECESSARY TO REPLACE LOW COOLANT SENSOR PROBE AND HOSE CLAMPS ON COOLANT RECOVERY HOSE-P/N 10054615 LOW COOLANT SENSOR PROBE AND 22527587 HOSE CLAMP-ALL 1986/1988 CHEVROLET CORVETTE MODELS TLH

 

[Edmond]

My neighbor came over and I talked to him about it. We started the car, turned the heat all the way up and left the radiator cap off. He revved the car up a few times and a little coolant spilled out. He said what you just said about air being trapped in there. The light is off now, but it still came on a few times when I took the car around the block.

I'm just going to monitor it for a couple of days and then see what happens.