What is normal operational temperature on W221 S550?
Thread Starter
Junior Member
Joined: Dec 2009
Posts: 49
Likes: 0
From: San Francisco, CA
2007 MB S550 Sport & 2010 GL 450
What is normal operational temperature on W221 S550?
I have 07 S550 and my engine temperature jumps from 80-100 is this normal? Also when it’s closer to 100 it’s making a small knocking noise. MB San Francisco telling me it’s normal. Should I be concern about this?
Your help is much appreciated
Thanks
Your help is much appreciated
Thanks
Member
Joined: Jul 2010
Posts: 95
Likes: 0
2007 S550
Every time I've seen something "odd" going on with coolant temp something bad has happened eventually, like a thermostat going out.
The w221 has an electronic thermo and claims to be better at managing coolant temps than normal mechanical thermos.
With newer cars I've never seen such behavior where you go above the target temperature and then go down. Even in hot places like palm springs and vegas. The cars are good at managing temps. They go up to the optimum and stay there circulating coolant and managing fans as needed.
The w221 has an electronic thermo and claims to be better at managing coolant temps than normal mechanical thermos.
With newer cars I've never seen such behavior where you go above the target temperature and then go down. Even in hot places like palm springs and vegas. The cars are good at managing temps. They go up to the optimum and stay there circulating coolant and managing fans as needed.
Super Member
Joined: Oct 2007
Posts: 643
Likes: 51
From: Southern California
2007 CL550
Check if the electric fan comes on when the temperature is at the upper end. Under this condition, just brake to a stop and leave the engine running. Roll down the driver's window and you should easily hear the electric fan. If you don't, then the cause of your increased temperature is caused by the fan not operating. It might be as simple as replacing a blown fuse. Otherwise either the fan temperature sensor or the fan motor has failed.
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Newbie
Joined: Dec 2015
Posts: 3
Likes: 0
2007 s550
im having the same problem
Im having the same problem with my s550 changed the radiator and thermostat now the temperature in the car jumps from 80 to 100 and it's winter, car drives sluggish.driving me crazy could some one please help and give me insight on what s going on and what to do
Senior Member
Joined: Mar 2015
Posts: 390
Likes: 26
From: USA
Mercedes-Benz 2007 S550, 2012 S550 4-Matic, 2014 S550 (Traded), 2015 GL450
Official temp should be 89C. When you changed the radiator and thermostat did you do the work yourself? My first guess is there may be some air trapped in the coolant system? Does the auxiliary radiator fan run?
Last edited by KNBS550; Dec 11, 2015 at 11:50 AM.
MBWorld Fanatic!
Joined: Nov 2014
Posts: 4,242
Likes: 628
From: Chicago burbs
2015 S550
Pushing air out of the system is easy. Just remove the radiator cap before it gets too hot and let the car run at full operating temp for a few minutes. Then put the cap back on and all air should be gone.
