With the engine cold, unplug the sensor electrical connector and measure the resistance across the sensor’s terminals. Plug the sensor’s electrical connector back in. Start the engine and let it idle for a few minutes. Turn off the engine, unplug the sensor’s electrical connector and measure its resistance again. MIGHTY5 said: my temps are never above 225f and thats gunning it all the way to vegas i have stage 2 rpi car. as long as you dont reach 250f your running within normal specs. MIGHTY the RPi oil cooler helps quite a bit. 2006 Supercharged BMW M5 ESS G2-680 Supercharger, Meth Injection, low compression engine build. 4984 posts · Joined 2008. #6 · Aug 9, 2011. Maximum coolant temp is the boiling point of your fluid. This is the point at which the vapor bubbles [and their poor thermal conductivity] in the coolant allow the engine to create more heat than the cooling system can exchange to the atmosphere; Due to nucleation of said bubbles along the engine's It would cycle between normal and hot back to normal. So I know the temp sending unit and gauge work to notify me of impending doom. 96 Z3 1.9 Black/tan/black. 97 M3/4 Estoril/dove gray. 08 3400HST Kubota Orange/gray. twh. 6101 posts · Joined 2015. #2 · Dec 25, 2017. It really isn't so much for telling how warm is the engine. But, yes, it does increase the RPM range as the engine warms up. If your RPM gauge white striped hash mark section doesn't slowly disappear as the engine warms up, then something isn't working. Reply Like. This makes sense as almost all cars' coolant temp gauges are at normal operating temp within 5 minutes or so. My 335i oil temp gauge doesn't get to 230-250 until 15 minutes or more of driving in temperate weather. F30 340i Estoril Blue/Oyster 6MT. E90 335i Sparkling Graphite/Black. Install the heater on maximum temperature, the fan on the lowest speed. Start the engine and let it run at idle. Fill the expansion tank with 250 ml above the maximum (250 MP meet the A = 18 mm). Run the engine for 15 minutes. Coolant is pumped automatically. Coolant level must fall to a mark. If necessary, correct the coolant level. My daughters car was also shutting off from the old unit overheating in the middle of the road. The dealer wanted to replace the fuel control module with 2 hrs labor for $800, while it cost me only $25 for the used module and 30 minutes to remove the seats and module and install the replacement and reinstall the seats. HriLyqS.