Flashing Temp Light

[peterbrown77]

On my drive to work, the temp light began slowly flashing.

New tank, new cap, temp normal, coolant tank half full......

Any ideas?

[seningen]

From a Search for the explanation....

From Loren@ rennlist -- 12 years ago!

Here is the long explaination 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."


If you have replaced things -- I would check that the sensor connection is secure, or maybe replace the sensor.

Mike

[peterbrown77]

Does it dead cold ....

[seningen]

Originally Posted by peterbrown77

Does it dead cold ....

Than it has to be something related to the coolant level sensor.

It's either bad or poorly connected.

Mike

[epapp]

A half filled coolant tank might be too low. There are indicators on the level sight and depending on what you consider half full might be just low enough to consider 'low'

[peterbrown77]

I filled to coolant tank almost to the top at lunch today. Started the car from cold, light still blinking.

Left work at the end of the day, checked the level (still full), light still blinking.

At the same point on the highway where it started blinking this morning, but going in the opposite direction, it stopped blinking.

So I'm figuring some kind of coolant-level-sensor-underground-doggie-fence in the vicinity of Haddam CT as the likely culprit. Who's with me?

[Jake Raby]

Originally Posted by peterbrown77

I filled to coolant tank almost to the top at lunch today. Started the car from cold, light still blinking.

Left work at the end of the day, checked the level (still full), light still blinking.

At the same point on the highway where it started blinking this morning, but going in the opposite direction, it stopped blinking.

So I'm figuring some kind of coolant-level-sensor-underground-doggie-fence in the vicinity of Haddam CT as the likely culprit. Who's with me?

Watch closely in the coming days to ensure that you don't encounter intermix in the oil or coolant. This is a classic scenario that could be a precursor to something that you can catch early on.

[peterbrown77]

I will.

At first I discounted it because I was having a heck of a time with my new coolant tank's bleeder valve AND the cap. I had condensation about the reservoir and it was a combination of a bad o-ring and the cap. It's been dry the past week but I thought perhaps through all the fiddling enough had evaporated to make the level borderline. Kind of surprised that topping it off didn't eliminate the light.

[peterbrown77]

Originally Posted by Jake Raby

Watch closely in the coming days to ensure that you don't encounter intermix in the oil or coolant. This is a classic scenario that could be a precursor to something that you can catch early on.

Jake -

I've been pondering this.

With a cold engine, I filled the coolant tank to the filler neck and started the engine. The light slowly blinked immediately, indicating low coolant which was clearly not the case.

Do you agree that it must be the sensor?

TIA

[epapp]

It would either be the coolant level sensor gone bad, or the engine compartment sensor gone bad, since either can trigger the slow blinking coolant light.

[peterbrown77]

And a week later, it started flashing again. Coolant tank is full, and even does it from dead cold so the overheated engine compartment doesn't make sense.

Unplugged the coolant level sensor and tried (as best I could in the dark) jumping the connector with a paper clip. Didn't help.

Any thoughts?

And: Where is the engine compartment temp sensor?

[peterbrown77]

Beuhler? Beuhler?

Hahah.

[epapp]

Well the problem is one of two dead sensors then (or both). I'm not sure what a good 'full' reading looks like to the ecu from the coolant level sensor, so shorting the two wires might still mean 'coolant level low' to the computer.

Since it probably DOES work like you thought (two wires shorted when coolant level is good), check the engine temp sensor. Its on the passenger side intake manifold between the throttle body and the plenums that attach to the head, you cant miss it, its the only sensor with wires coming out of it atop the passenger intake. Maybe there are some docs online that explain how each sensor works so you can test them (I dont have the bentley book with me all summer)

[runjmc2]

If you had a durametric you could take a look at the engine compartment temperature. That would show that value that the engine compartment sensor is sending. When I had that issue, it was the engine compartment sensor fell out of it's grommet and was laying on the manifold. That would not explain a blinking light when the engine it cold but a durametric will show the value it is sending (e.g. is that sensor bad. I also wonder if the engine compartment sensor was bad if the engine compartment fan would be running????

[peterbrown77]

You would think that if it thought the compartment was overheated, the fans would be going full bore.

[peterbrown77]

In Porsche fashion, they decided to go the other way - the coolant level sensor is a normally open circuit. Unplugging the connector made the light stop flashing. Who da thunk it?

[guesswecan777]

Did u check the coolant temp reservoir?

[peterbrown77]

Originally Posted by guesswecan777

Did u check the coolant temp reservoir?

I think I know what you mean, and - yes - the level has been fine all along.

[peterbrown77]

Another pleasant hour of my Sunday dealing with Porsche "engineering" (if it can be called that).

Replaced the coolant level sensor with new, plugged it in, and drumroll ----- the light still flashes. So, if it's unplugged it doesn't flash. Which it currently is. I'm not going to get into the rank stupidity that has me remove 2 pieces of carpet and then loosen the entire tank to get the sensor out because they thought it would be a grand idea to position the sensor directly above one of the body seams so you can't drop it out without a written consent decree.

I guess it has to be the float? I can see that it is at the top of it's travel when it reaches a push-on retaining clip. Maybe I should somehow push the clip farther down the float's spindle?

[epapp]

Did you check the engine compartment temp sensor for proper functionality?