2000 996 Carrera 2 coupe 6 speed - Red coolant light

[Philip54]

The red light on the coolant temperature gauge of my car occasionally (but in recent times more frequently) flashes slowly (0.5 Hz).

 

In a post dated 7/30/2018 Loren listed four conditions for the light to come on.  The two conditions for which the light flashes slowly (0.5 Hz) are the following:

 

• Engine coolant too low

• Engine compartment temperature too high

 

None of these conditions applies to my car.

 

The light comes on after about 20 minutes of driving and it seems to be triggered (but not always) by running the engine above 4,500-5,000 RPM (with coolant temperature at normal values and, I assume, engine compartment temperature also at normal values.  This is not driving in heavy traffic, this is normal out of town driving ).

 

Using  the Porsche tester it was possible to establish that the engine compartment fan works.  However,  it does not come on when I drive the car in traffic and the coolant temperature gets to 215F.  This, I would assume, should cause the engine compartment temperature to become elevated and the fan to run.

 

The engine compartment sensor, located on the passenger side intake manifold, is installed properly  and seems to read the temperature of the engine compartment correctly.

 

Any thoughts on what is going on?

 

Thanks

 

[JFP in PA]

Could be as simple as the level sensor going bad.

[Philip54]

Thanks for your reply.

 

Is there any way to test the level sensor or the only option is to replace it and see if the problem goes away? 

[JFP in PA]

If memory serves, the level sensor is a simple on/off switch, you should be able to test it using a multi meter and moving the sensor to see if goes on and off.

[DBJoe996]

Are you sure about the coolant level?  Did you open the cap and check?  I agree with the suggestion to replace the coolant expansion tank level sensor.  It is outside the coolant tank so you won't lose any coolant.  215F is pretty darn high.  How are you getting the car that hot?  Are your radiator fans working?  Has the thermostat ever been replaced?  What mix is your coolant and is it pink (the new type coolant)?

Edited May 8, 2020 by DBJoe996

[Philip54]

1 hour ago, JFP in PA said:

If memory serves, the level sensor is a simple on/off switch, you should be able to test it using a multi meter and moving the sensor to see if goes on and off.

Thanks.   We'll give it a try.

[Philip54]

1 hour ago, DBJoe996 said:

Are you sure about the coolant level?  Did you open the cap and check?  I agree with the suggestion to replace the coolant expansion tank level sensor.  It is outside the coolant tank so you won't lose any coolant.  215F is pretty darn high.  How are you getting the car that hot?  Are your radiator fans working?  Has the thermostat ever been replaced?  What mix is your coolant and is it pink (the new type coolant)?

I confirmed that the level of coolant was correct by removing the cap and checking.  I occasionally get to 215F in slow traffic, because of the South Texas heat in the summer.  The thermostat has never been replaced, the water pump has (the car has about 125,000 miles).  Next week we will be looking for a freon leak in the A/C system and that will be an opportunity to check radiators and radiators fans.  I am told that I have the correct coolant.

[JFP in PA]

21 minutes ago, Philip54 said:

I confirmed that the level of coolant was correct by removing the cap and checking.  I occasionally get to 215F in slow traffic, because of the South Texas heat in the summer.  The thermostat has never been replaced, the water pump has (the car has about 125,000 miles).  Next week we will be looking for a freon leak in the A/C system and that will be an opportunity to check radiators and radiators fans.  I am told that I have the correct coolant.

 

In that environment, 215 F would not be unusual with the factory thermostat.