E36 code reader reading hot temp gauge stays in middle

[EzHoopty]

I have a 97 328ic that seems to be getting way too hot. I have only been letting it idle and maybe go around the block a few times so I haven't really done much driving in it. the temp gauge stays in the middle after it warms up for a bit. But I've been leaving my reader plugged in just to look at everything and its been staying hot. Like anywhere from 114-120°C but the gauge is still right in the middle. So I'm wondering what could be wrong with the cooling system?

[jc43089]

The gauge is set up to not be linear, there is a wide range of temperature that will be indicated as dead center on the gauge. Not good if you ask me because if the gauge goes past center it's usually too late.

Do your fans work? That is pretty hot on the OBD2 reader. It should be accurate. Why are you just idling around the block? Does the temp steady out around 92C while driving at speed? 92C is stock thermostat temperature. The Aux fan should come on low speed at 91C (at the cold side of the radiator) and high speed at 99 C. I like to swap that temp switch in the radiator to the 80/88C version. It's a stock BMW part and helps by turning the Aux fan on sooner, then it is no problem to remove the mechanical fan.

[EzHoopty]

The main fan works but has some broken blades I have a new one on the way. Idk if the aux fan is working. I didn't see it on when it idling in the driveway but not sure if it was warm yet or not. Just going around the block because I was trying out some things with the suspension I've changed up. And also once I saw that temp get to 120°c I was scared to drive it because I thought that was way too hot. I knew about gauge not being linear but shouldn't it move long before it gets to 120°c?

[jc43089]

I'm not sure the actual curve for the gauge but it is pretty much useless. I would be scared too if I saw 120C. That is quite hot.

[XnWarden]

Got air in the system? I had a leak develop today at the expansion tank. Drove with the gauge 1/4 past the halfway for a few minutes until i could pull over. I wept silently the entire time because i know the possibilities....

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[ChuckDizzle]

You can remove the buffer in the temperature gauge, there was a thread a while that detailed the procedure. For the non-enthusiast, seeing the temperature gauge move in real time with the actual temperature would probably make them very uneasy.

[JDStrickland]

Broken fan blades is never good.

Does the temp go down when the car is moving? If yes, then my thoughts are that the fan clutch is failing, or has failed. When the car is moving at speeds above about 30, the air that is forced through the radiator will be sufficient to keep it cool, but when the car stops moving, the fan clutch comes into play by locking the fan to the serpentine belt and drawing air through the radiator. When the fan clutch fails, then you have no, or insufficient, airflow through the radiator when the car comes to a stop, typically in stop-n-go traffic. 120°C is 248°F, this should bother you a little bit.

Before you do anything, fix the fan. You have lost a significant percentage of its capacity through broken blades. Being out of balance is never good.

[EzHoopty]

Thanks for the help everyone. I figured out that the cheap code reader that was used was reading at least 15°c high. Tried a different reader and it was totally normal temps

[hli]

Keep in mind the OBD reader is going to read higher because the sensor is right in the head. Mine fluctuates between 205 and 215F at full operating temperature with a 88C thermostat.

[golgo13]

You can remove the buffer in the temperature gauge, there was a thread a while that detailed the procedure. For the non-enthusiast, seeing the temperature gauge move in real time with the actual temperature would probably make them very uneasy.

I did this exact thing in my track car. I basically change the temp curve so it's more linear and less of a bell curve in how the needle displays temperature. It works pretty well, you can watch it swing when you are beating on the car and when it's cooler outside, etc.

Some discussion here:

https://www.bimmerforums.com/forum/s...nector-Madness

[jmo69]

One of the reasons I put an aftermarket gauge in. The sender is in the coolant line to the throttle body. Runs at about 200°F, 92°C thermostat.

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