LFA

1991 GT;
The Coolant Temperature Gauge needle at the instrument cluster reaches the white bar between 80 and 90 and stays there when the car is running and at steady state. is this normal? Shouldn't it stay at 80 and not go further above. I hear the fan starting but not sure if one or 2 of them are running . Could this be due to a fault at fan controller?

Thanks for all your help. I very much appreciate it.
Best regards,

LFA

Correction; the needle reaches the white bar between 80 and 100

StratfordShark

Well that's where my needle sits on 1991 S4, and it's been like that since owning car, and after new rad, new t-stat and seal and coolant changes, so I'm not worried! I don't think that gauge is terribly accurate.

Tampa 928s

Testing the gauge temperature sensor?

Trying to find the Ohm specfacations or procedure for testing cold - hot at the Gauge temperature sending sensor. I want to record the changes as it warms up but mainly want to see if it is within specfacations.
Thanks

Jetdriver69

My 82 would always run high on the temp gauge even though the coolant was actually in the normal range.

I mounted a variable resistor (a 25 ohm potentiometer from RadioSack) wired from the power lead and ground from the temp gauge sensor to the resistor and then back to the sensor.

I then got the engine up to temperature and measured the coolant temp with an IR gun.

The coolant was 185-190F coming out and about 165-170F going back in. The 928 Motorsports aluminum rad is a bit more efficient than an old and probably semi clogged Behr.

Now just turn the **** on the variable resistor until the gauge shows middle of the range when the coolant is normal temp. It took about 16 ohms resistance to make the gauge accurate.

My electric fan is set to come on between 185 and 190F and the gauge seems very accurate now. Simple fix that cost less than $10.

Now I need to make my voltmeter more accurate...time to take the pod off.

FLYVMO

I believe the stock thermostat is in the 83-85 degree celsius range, so I would think an indication of upper 80's to 90 celsius is pretty normal. There is a lower temperature thermostat available (75 degrees celsius) that will let the car run a little cooler, however I'm sure there is a reason Porsche chose the thermostat they did, probably emissions requirements among other things.

Cheers!
Carl

Hilton

My 89 sits between the 80 and 90 marks - about 87 degrees by guesstimation.