Blinking temperature light.

[Nick_Esc]

Hello everyone. I have a '99 c2 with 71K on it. Ever since yesterday, when I am driving the red light on the "hot-side" of the temp gauge blinks. The car cannot be hot since it does it even when I have let it cool for a couple of hours. The temp gauge seems to work normally besides that. The needle rises and stays put at just between the 8 and the 0, so that seems ok. Does anyone know why this happens? Thanks!

-Nick

[Eric (Plug Guy)]

Hello everyone. I have a '99 c2 with 71K on it. Ever since yesterday, when I am driving the red light on the "hot-side" of the temp gauge blinks. The car cannot be hot since it does it even when I have let it cool for a couple of hours. The temp gauge seems to work normally besides that. The needle rises and stays put at just between the 8 and the 0, so that seems ok. Does anyone know why this happens? Thanks!

-Nick

Check your coolant, may be low.

[Izzy]

I had the same issue with my 99, and the coolant level was a little low, only 1/2 a cup. That much less volume and some "spirited driving" will send the light to blink. I found the small coolant leak, parts on order.

[Loren]

Covers all Carrera (996), GT3, TT / GT2 and Boxster (986) cars

Here is the long explanation from the service 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."

[Nick_Esc]

Thanks everyone, it sounds like i need to buy some coolant and see if that works. Thanks for you help!

--Nick

[Loren]

Thanks everyone, it sounds like i need to buy some coolant and see if that works. Thanks for you help!

--Nick

If you add more than 8 ounces of coolant then I think I would also look for leaks. The older caps (part number ending in 00) are not very good and should be replaced with 01 caps. The tank should also be inspected as well as the hoses. Good luck!

[Mark Kress]

Here is my situation... 1999 Porsche 911 C4

I went to the race-track and overheated the car... after that when I started the car when it is cold the temp pointer is pinned to the right and the light blinks slowly, but after a little bit of driving the temp pointer reads temp accurately and light turned off.
After completing the following "fixes" when I start car cold the light blinks and the temp pointer is to the right, but after a little bit of driving the temp pointer reads temp accurately but now the light stays on. If I start the car warm the only thing that happens is the light blinks slowly.

To fix the initial issue I did the following:
Replaced the coolant tank,
Replaced the reservoir CAP with the black one
Replaced the coolant level sensor
Replaced the Engine Coolant Temperature Sensor
I also tested the engine compartment blower and it works fine.

My only guess is that the wiring on the coolant level sensor is broken. When I replaced the tank I noticed the old one was not mounted in the car and was able to flop around.

Any ideas?

Thanks

Mark

[Loren]

On 12/9/2005 at 6:06 AM, Loren said:

Covers all Carrera (996), GT3, TT / GT2 and Boxster (986) cars

Here is the long explanation from the service 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."

 

 

What speed is the light flashing at?

[Abirob]

Hi, I have a 2000 carrera 4 cab, with 49k miles - my light blinks slowly ( even when cold) - coolant level fine.

 

thoughts?' I have anew resavoir cap on order - looking for a coolant sensor - struggling to locate a part number? Without taking the old one out 

[JFP in PA]

3 minutes ago, Abirob said:

Hi, I have a 2000 carrera 4 cab, with 49k miles - my light blinks slowly ( even when cold) - coolant level fine.

 

thoughts?' I have anew resavoir cap on order - looking for a coolant sensor - struggling to locate a part number? Without taking the old one out 

 

You want the cap that ends in -04, 996-106-447-04.

[Abirob]

Thank you - appreciated - parts outlet has confirmed this also

regards

neil

[DBJoe996]

Coolant sensor #27 here 

M96.01/02/03 Oil Pump M96.04

WWW.AUTOATLANTA.COM

---

 

 

[enzo66t]

Hi,

1999 996 37K miles. 

Have the slow temp light blinking condition.

 

Coolant level adequate 

Engine compartment fan works

Engine shows no objective sign of overheating 

Temperature on guage is normal around 195-200

Car performance is normal

 

Brought to an independent shop who I know and trust for a long time.

 

They pressure tested the system and felt there was a small leak in the coolant tank. They replaced the tank, cap, also did a new thermostat and coolant level sensor. 

 

No luck. Since they could not figure it out they did not charge me at all for the job. They sent it to local Porsche who let the car sit for 3 weeks and I got fed up with that and took the car back.

 

Any questions or thoughts from the group??

 

I didn't pull or ask for the error codes I am going to use my machine to check that. 

[Loren]

Tank water level sensor.

[enzo66t]

coolant level sensor was replaced 

same thing Loren?

[Loren]

2 hours ago, enzo66t said:

coolant level sensor was replaced 

same thing Loren?

 

Covers all Carrera (996), GT3, TT / GT2 and Boxster (986) cars

Here is the long explanation from the service 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."

[enzo66t]

Yes thanks Loren.

NONE of these conditions are present but I still get the slow blink, despite also all of the above repair work being done. I'm stuck...

[Loren]

Has the coolant been replaced or topped up lately?  If so, then you may have trapped air in the motor.

[enzo66t]

It was with the job they did above. But the light was present before any of that.  I lifted the clip on the reservoir to leave the vent open and have driven it a bit like that. Would thar clear any trapped air ? 

[JFP in PA]

27 minutes ago, enzo66t said:

It was with the job they did above. But the light was present before any of that.  I lifted the clip on the reservoir to leave the vent open and have driven it a bit like that. Would thar clear any trapped air ? 

 

Perhaps, but the best way to remove any trapped air is with a vacuum filling system, which can be used on an already full system to "burp" out any air. 

[enzo66t]

Thanks. Vacuum filling systems.... something I can buy and do easily myself or major equiptment I should expect a shop to have ?

 

Would you agree that based on above work done this is the main place to look (air trapped)? I cannot see any other reasona based on everything that was done and what I've read about the possible causes for a slow (or fast) blink 

 

Thanks to the group 

 

 

[JFP in PA]

Amazon sells them, as do almost any auto tool outlets, very common tool in just about any well-equipped shop:

 

 

Unfortunately, it is very easy to trap air in Porsche systems, and getting it out is just about an everyday question here and on other Porsche technical forums.

 

[ABVH]

On 4/19/2023 at 11:02 PM, Loren said:

Has the coolant been replaced or topped up lately?  If so, then you may have trapped air in the motor.

 

On 4/19/2023 at 10:57 PM, enzo66t said:

Yes thanks Loren.

NONE of these conditions are present but I still get the slow blink, despite also all of the above repair work being done. I'm stuck...

 

hi, i am facing the same problem here for past 3 months, temp light was blinking slowly and coolant temp was around 90-95 celcius, zero coolant leak, it always happen when car is idled at traffic, compartment fan working...

 

i have replaced a long list of items:

 

1, both radiators (csf)

2, both radiator fan (low and high speed are good)

3, coolant temp sensor

4, coolant level sensor

5, water pump and thermostat

6, bleed the system twice, no trapped air or bubbles

 

and the light still blinks slowly after ~20min of city drive and stuck at traffic... 

 

i am really running out of ideas now...

 

[Loren]

Bad sensor in the coolant tank?

[ABVH]

22 minutes ago, Loren said:

Bad sensor in the coolant tank?

 

you mean the coolant level sensor? that has been changed.

 

now i am thinking probably caused by "high engine compartment temperature" 

 

but it looks normal to me...

 

 

 

this blinks only when the car is on idle, like i said, zero coolant loss, both coolant level & temp sensor have been changed.

 

 

 

 

Edited March 27 by ABVH