Darien

Has anyone ever compared an external temperature reading to the white hash marks on the intereior gauge?

Since I don't have any way of checking the actual temperature, I don't know when my Aux Fan should be activated by the radiator switch in relation to my temp gauge. Should it come on at the 2nd or 3rd white mark or does it wait until it hits the bottom of the red? I currently have the 92 deg switch.

Tony

Hey Darien, if you had your eyes open when i gave you a ride in mine you could have seen for yourself. Granted mine's an S4 but i dont think the calibration is that much different. Even in the hot weather of late and the "testing" ive been doing, my needle has yet to go beyond the center of the gauge. The corresponding water temp there was appx 215-220 on the aftermarket one i have.


An idea would be to get an IR gun and shoot the radiator? I had one but it got a little wet a while back...Actually i need to get another one one of these days..

Perhaps Mike can fire up the FLIR on a F-22(if it has one) and pickle your radiator....from what...200 miles!

SharkSkin

It varies from car to car... You'll have to measure if you want any meaningful comparison to actual temperature.

Drmark

I'm with Dave - the dash guage is not a particularly accurate instrument and there is wide car to car variation, particularly in later S4s GT and GTS which tend to read higher in my experience (and cause a lot of concern when owners compare them with others).

Rich9928p

I have an Autometer water temp gauge in my track car ('79). The temp probe is mounted in a cap that covers a water passage on the very back of the head on the drivers side. When the gauge reads 210F water temp, the dash gauge reads just a little below the 2/3 (2nds white mark).

My S4 normal winter reading is a needle or two width below the 2nd mark, and summer reading with A/C blasting on full (105F+ ambient) is at or a few need widths above the 2nd mark.

IMHO, as long as the indicator is not in the red zone or the needle isn't moving fast upwards towards the red zone, you are OK. If the reading is above the 2/3 mark, reduce power and turn off the A/C and see if the needle drops. If it does drop, you're OK - go back to your A/C and high power ways. Just keep it out of the red.

IcemanG17

The general consensus I get from other owners is the first white line is around 175 degrees and the second white line is around 210 degrees...based on an S4....but individual cars will vary quite a bit.
Mine tends to stay around the 1st white line, but with the A/C on in hot weather it will climb to about the middle (1/2 way between both gauges)...I would guess even higher for track work in hot weather.
Brian

MikeN

Spot on here. The '89 and later temp guage gets a lot of people excited......its not normal in the automotive world that a temp needle being at the 3/4 position is considered "normal".......it is in the 928 world though. When my GTs needle is at the 210 mark its pretty much running 10-20 degrees cooler than that.....verified by an infra-red thermometer. In fact it mostly floats around the 190 degree mark......right around where the thermostat/fans should maintain it. Only goes a little higher in very high temps with A/C on.

SharkSkin

As I've said, it varies.... on my 78, the needle is just beginning to touch the red at 200°F. First mark is about 160, second is about 180... verified with a thermcouple in the coolant stream.