I thought the temp gauge might be broken then after a while of driving I saw it was going up very slowly, and it stopped a little above the cold line, so I replaced the thermostat and it heats up at the right rate now, but only to the same place, what suggestions do you have for the next step? im thinking fan or radiator cap

 

Not sure what the problem could be but I do have a few suggestions. First, make sure to use an oem thermostat and not a generic one from the parts store. Secondly I would strongly suggest installing an aftermarket temp gauge, the s4 temp gauge is actually pretty good but overheating your engine is not something you want to do and a good aftermarket one will let you know exactly what temp you're running.

Also, my stock gauge sits about 1/4 of the way between the hot and cold line when fully warmed up.

 

ya believe me man I check that temp gauge probably once every five seconds while driving hard or just in general but I feel like the s4 stock gauge just likes to sit low even at the correct operating temp

 

I thought I was having the same problem a while ago but the gauge actually reads a little funny. I posted on this forum about it and a guy commented back and said a 1/4 to a 1/3 is about where it needs to stay




As long as its right around this range it's fine... I run mine all day long like this and when I do get my car out I'm usually driving it pretty hard