Coolant “Indicator failure” after installing LTT?

[RS_MAT]

Hi Guys,

Hoping someone can provide some advice, I have a 2005 997 C2S Manual that has been running great but as a preventative measure due to meant to be driving across Europe this summer yesterday I installed a low temp thermostat which was a bit fiddly to do but not too bad and straightforward enough.

However when I then started the car up to bleed the coolant system I noticed that my coolant temperature gauge was reading “zero” and the red warning light was flashing which I believe means low coolant level.

Anyway I topped the coolant level up and warmed the engine up to engine oil operating temp (just below 90 deg) however the coolant temp gauge still shows zero and continues to flash red.

I believe I have bleed the coolant system correctly, water in header tank is getting hot, interior heater blowers are blowing lovely and warm, and the roads feel warm to touch.

I have been for 18 miles round trip to taking shopping to my parents and when I stopped there I added some extra coolant maybe 300ml.

Throughout my drive the engine oil temperature has remained just below 90 deg and still no reading from coolant gauge.

I have removed, checked and cleaned the plugs and terminals on both coolant temp and coolant level sensors.

I was thinking the coolant temp sensor has failed but also thinking it’s too much of a coincidence for me to change the thermostat and flush the coolant system and then then my coolant temperature gauge doesn’t work 🤷‍♂️.

Anyway sorry for the long post but wanted to provide as much information as possible.

Cheers
Matt

[edc]

If you had to add 300ml after a short drive have you eliminated the possibility of a leak and have you really bled the system properly?

[LennyM1984]

If there is no leak, an airlock may be the issue. Bleeding the porsche coolant systems is a bit of a faff. Pelican parts have probably the best guide this side of using a vacuum bleeder

[Pope]

Almost certainly you have induced an air lock.

Do not drive the car until you have confirmed that you have removed all the air.

The only way you could be sure is if you measured the amount of coolant you removed and have managed to refill the same amount.

'Failure indicator'is usually as a result of the calculated temp not matching the actual temp - the DME knows that for a given start temp/run time/fuel throughput what the engine temp 'SHOULD' be - if it's out of parameters it will log the fault.

[RS_MAT]

Hi, I have had a good look and there are no visible signs of a leak anywhere and also not around the thermostat I replaced.

As you say there maybe still some air in the system, I’ve just checked coolant level again now it’s been parked and allowed to cool for a few hours and the header tank level has dropped from max to just above min so will top up again.

Just couldn’t understand what the coolant temp gauge wouldn’t give any temp reading at all.

[LennyM1984]

I think you probably need to rebleed it. Follow the pelican process. It'll ps off your neighbours but it's better than having air in the system

[RS_MAT]

LennyM1984 said:

I think you probably need to rebleed it. Follow the pelican process. It'll ps off your neighbours but it's better than having air in the system

I will take a look at that thanks and let you know

[RS_MAT]

Dropped the car off at a Porker Specialist today and was a simple fix, literally a delete /reset of a low coolant error code and the coolant gauge then worked normally, drive it the 15 miles back and it’s not reappeared so fingers crossed all is ok.

Coolant system was also checked and no apparent air locks appeared to be present, no coolant leaks etc.

Thanks for everyone’s help and advice

[Pope]

Good result; thanks for the update.