I have an '00 E320. Just recently, the temperature guage has been giving me a reading that is at least 30 degrees below what it should be. It is kind of odd, it starts out fine. Right as I start my car, for example, it will show 40 degrees (fairly accurate). But within less than a minute, I will see it drop down to about 8 degrees.

Anybody else have this happen to them? Any idea what could be causing it and what a solution could be?

 

change the temperature probe, it is located behind the louvers underneath your bumper impact strip

 

AMBIENT TEMP SENSOR Is probably failing...easy to replace, its a little point you should see sticking out of black mesh area next to drivers side fog light. You have to open hatch underneath car wear you access fog light to replace.

Its pretty easy once you get underneath and open hatch...it may have fell out of place, so check to see if you see if pointy object sticking out of front mesh area first. Part is cheap about $15 on line or 20 bucks from dealer.

SEE THREAD
https://mbworld.org/forums/showthrea...ht=TEMP+SENSOR

 

This Is The Part In Question It is plug in play.