I read in the manual that the blinking red light on temp gauge and warning in the speedo display means low coolant level. I'll check tomorrow when the engine is cool if the coolant level is between the lines. In the meantime is your advice to simply add coolant or should I be looking elsewhere for a fault or problem? /X3

 

My 99 C2 always blinks. Hoping for a solution, the PO put a piece of black tape over it

 

Have you physically checked the coolant level? That would lie my first suggestion. If it is down, add distilled water and pay attention to how much you add, then go hunting for leaks.

 

manual on the flashing coolant light.

"Four functions of the coolant warning light:

1. Engine coolant level too low -- light flashes slowly (0.5 Hz)

2. Engine compartment temperature too high -- light flashes slowly (0.5 Hz) (engine compartment blower might be faulty)

3. Engine coolant temperature too high -- light is lit; pointer on the right

4. Temperature sensor at water outlet faulty -- light flashes rapidly (1 Hz) ; pointer on the right

Note: The temperature warning in point three is indicated if the conditions "engine coolant temperature too high" and "engine coolant level too low" are present simultaneously."

 

And if you happen to have UAOS, slow blink can mean accumulator needs draining.

 

OP - Probably a good time for you to check your coolant level sensor. On 98-00 model expansion tanks the sensor is underneath. On 01-04 the sensor is back behind tank and above the left wheel arch. Check the temp sensor behind the oil pump on lower right rear of engine. Wire or connector could be damaged. Sensor could be bad, depends on the blink frequency. Both parts are cheap and are easy enough to access. Bentley manual has test values if you want to check the connectors.

 

If it's blinking slowly and your coolant level is fine, you probably need to replace the sensor. The part is only about $30.

 

thank you, I’ll look into the sensor. I have a 99, should be on the bottom. Can I bypass the sensor to test? I suspect the wires are broken/cut or the sensor is bad.

 

You can just unplug the low coolant sensor, if the blinking stops. then you have either a bad sensor, or the magnetic float in the reservoir has sank..

 

So I followed the advice to add distilled water when the engine is cool, then hunt for leaks. Sure enough coolant leaking from in front of expansion tank near the back of the left-rear wheel. The expansion tank, cap and sensor were all replaced at Porsche dealer in 2018, about 8,000 miles ago, so hard to believe it's the tank again. What do you think? /X3

 

Its probably the tank, they suck. Maybe its under warrente still?

 

996.1s seem to be notorious for tank failures, but most seem to be aftermarket versions. Maybe try pulling some things away from the tank and confirm where it is...maybe a line, rather than the tanks too.

 

 

Just a note: my temp light was slow blinking. Looked in engine bay and found the engine temp gauge sending unit was sitting on block. The gauge is located in the engine bay on the front right side on top of the manifold and should be held in with a rubber gromet. My gromet was missing and the sending unit was sitting loose. Bought a new engine temp gauge and gromet from Pelican Parts for $30+ship.
Worked. No blinking light anymore. Found a tip to look for this issue after endless forum searching. Maybe this will help someone.

 

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