MNR

my owners manual doesnt give a number it just says it may rise into the red zone during hot days. so mine fluctuates between 88 and 97 celsius. is that typical for this car?

kaype

yes it is!

NAFT1

New radiator; mine goes from 90-100C during the Texas summer.

wasp01amg

Saturday over 100F outside, coolant was 80-90C while cruising down the highway.

Nocturnal-G

The gauge on my E55 isn't accurate... mine doesn't go over 100 Celsius on the gauge. However when I check using the cars built in diagnostic, it reads much higher.

To access the diagnostic readout... Press and hold the REST button until a readout appears, using the AUTO buttons toggle to 6. It should give you a readout in Fahrenheit. The highest I've seen is 220 Farenheit. I'm usually at 184-200 cruising...

Interested in what other E55s readout...

Tall Giraffe

I bought an IOS bluetooth OBD2 and it reads 199 running temp @ 94 degrees outside temp today