Ok I have the marshall water temp guage, I also picked up a obdII adapter to read codes with the torque app. Well tonight I noticed the app says my coolant temp was 230 degrees and the temp guage was reading 190. Yeah I know their hotlink adapter for the water temp won't be the most accurate way to measure water temp but is it really off 40 degrees or could the app be off? Outside temp is 30 degrees and I drove 75mph home tonight for 15 min and the marshall guage never went over 190.

 

If you aren't tuned the temp can max out at 230f, for emissions purposes, but if you get on it then it quickly drops to 190. Depending on year the sport button or blasting the AC full cold will also drop it to 190.

 

Sport mode on 100% of the time. A.c. off for another few months ha. Tmrw I'll get on it and see what it does all while seeing what the cravenspeed temp guage does. When the temps are in the high 40 low 50s the craven speed guage was reading 220. Just strange that the app was reading 230 while the guage was only 190. If the car is at 230 the thermostat should be open? So I would think the guage would be higher. But hey I don't have an engineering degree ha.

 

the thermostat is computer controlled which is why it holds temps so high on purpose. do the gauges agree when the car is cold up till it reaches normal operating temp (<190F)?

 

I'll have to check in the morning. I never really looked at the temp guage on the app until tonight. So the thermostat is all computer controlled, so it doesn't open and close just from coolant temp?

 

Yup, it also looks like an artificial heart. It has a sensor and a connector to open the valve via ECU but it does have a failsafe bypass I believe which is temperature controlled if all else fails

 

I had the same thing, replaced the sensor and all was well again. A new one from Marshall was about $20.

Also check your wiring to make sure there are no corroded connections. The sensor is a just a resistor that varies with temperature, the resistance decreases as the temperature goes up. So if you have any bad connections that will cause the gauge to read low.

 

Just realised I said "cravenspeed guage" in my original post when I was going to say "marshall guages" but you and everyone else understood, I feel dumb haha. And I didn't even think to check my connections. I'll check the connection right at the sensor tmrw and see if anything changes, if not I'll replace it and see if that does anything.