Hey I was searching but I can not find a good answer to my question. I have read that people run between 150F - 210F. My question is on my S4 Temp gauge (don't have an aftermarket one yet) how do I know I have reached that? What how many degrees is it when it's half way? Is half way on my gauge like 180? Let me know. What is 1/4, 1/2, 3/4 I really hope to get some answers

 

Nobody is running 150°F.

From what I understand, "NORMAL" (185-190°F) on a S4 gauge is about 1/4 - 1/3.
I don't know how linear the reading is.

 

So past half would be exceeding the maximum temperature? ++210F?

 

Yes... 210F would be extremely bad... Like crossing the streams Ray. Oh sorry just thought of Ghostbusters. They say 195F is bad and can cause an engine to pop.

 

195 will not cause a engine to pop, thats just crazy talk

I can confirm clokkers findings, I use 3 temp gauges in the car and 180-190 is about 1/3 up the s4 gauge

 

Whose "they"? The thermostat doesn't fully open till 195F. That is completely normal operating temperature. 210F isn't bad after a lot of boosting either. I believe 220 is when you need to shut down. There are a number of threads with info on water temps under different conditions.

 

I got an S4.. My temp gauge hardly leaves bottom. well maybe a few milimeters above the line

 

Note the typo in the service manual... I believe crack temperature is supposed to be 177-183 F. The factory thermostat is fully open at 203 F. I find it hard to believe that temperature would be dangerous for the engine, otherwise Mazda would have designed the thermostat to fully open lower than that. I have been doing comparisons between my Power FC (reading the factory thermosensor on the waterpump housing) and the stock s4 temp gauge. Today with the ECU reading 93 C (maybe 200 F) I was about a 1/4 of the way up. At temperatures in the low 80 C range (mid 180s) the needle was just a little bit above the "cold" line. Now the gauge sending unit is on the rear iron, but those two temperatures can't be far off enough to matter much.

 

ok cool so 1/3 of the way is approximately 190F? So when it reaches the Half way mark (1/2) how much more is it 10degrees? 20?

 

when my car was NA it never, ever moved off 180-190, it ran so nice and cool when it was stock, solid cool like clockwork. If you go above half I dont know what the temp is but I would take it easy or just make sure nothing is wrong.

then I boosted the car and now I constantly stare at the temp gauge, lol