SL/R230: Normal Engine Operating Temperature?
Thread Starter
Member
Joined: Sep 2018
Posts: 175
Likes: 74
From: Tremonton, Utah
2014 E350 Sport 4Matic Sedan
Normal Engine Operating Temperature?
For those of you with the 2007-2009 SL550 with the M273 engine, what is the normal engine operating temperature that most of you observe on your coolant temperature gauge?
I've recently replaced the thermostat on my '07 SL550, and the temperature now stays at right about 92-93°C. When I first got the car, the temperature was running about 85-88°C. I'm curious if the new thermostat is running high, or if the old thermostat was already going bad when I bought the car. I've done a lot of online research and can't find anything that states what the correct thermostat temperature is supposed to be.
I've recently replaced the thermostat on my '07 SL550, and the temperature now stays at right about 92-93°C. When I first got the car, the temperature was running about 85-88°C. I'm curious if the new thermostat is running high, or if the old thermostat was already going bad when I bought the car. I've done a lot of online research and can't find anything that states what the correct thermostat temperature is supposed to be.
Junior Member
Joined: Jan 2019
Posts: 37
Likes: 3
2004 SL500 r230
what is the question? is it when does thermostat starts to open? even that is an approximation.
or is it what is a normal operating temperature for an engine? that would depend on outside temp.
manufacturers like to run high temp for emission and efficiency reason. but anything over 100c is considered hot... anything over 110c is a big no no...
btw, what temp thermostats open ultimately don't have to do with what coolant temp ends up to be in a long drive (in a warm weather). it mainly affects how fast it reaches that temp.
or is it what is a normal operating temperature for an engine? that would depend on outside temp.
manufacturers like to run high temp for emission and efficiency reason. but anything over 100c is considered hot... anything over 110c is a big no no...
btw, what temp thermostats open ultimately don't have to do with what coolant temp ends up to be in a long drive (in a warm weather). it mainly affects how fast it reaches that temp.
Thread Starter
Member
Joined: Sep 2018
Posts: 175
Likes: 74
From: Tremonton, Utah
2014 E350 Sport 4Matic Sedan
what is the question? is it when does thermostat starts to open? even that is an approximation.
or is it what is a normal operating temperature for an engine? that would depend on outside temp.
manufacturers like to run high temp for emission and efficiency reason. but anything over 100c is considered hot... anything over 110c is a big no no...
btw, what temp thermostats open ultimately don't have to do with what coolant temp ends up to be in a long drive (in a warm weather). it mainly affects how fast it reaches that temp.
or is it what is a normal operating temperature for an engine? that would depend on outside temp.
manufacturers like to run high temp for emission and efficiency reason. but anything over 100c is considered hot... anything over 110c is a big no no...
btw, what temp thermostats open ultimately don't have to do with what coolant temp ends up to be in a long drive (in a warm weather). it mainly affects how fast it reaches that temp.
My understanding of the function of a thermostat is somewhat different than yours. Yes, the thermostat does control how fast an engine gets to operating temperature. But my understanding is that, with modern cars it's function is also to assist in maintaining the engine at an ideal temperature for efficient operation. The thermostat helps maintain temperature by not only opening at the right temperature, but also by closing. This is particularly important in cooler weather. An ecu throws a code when engine temperature runs lower than normal because a cold running engine does not run efficiently. In most cases, replacing the thermostat fixes this.
Senior Member
Joined: Aug 2010
Posts: 359
Likes: 291
From: Rockport, TX
2007 S65 AMG-Sold, 2007 SL55 P030 - 2016 GL450 - - 2017 AMG GTS - Sold - 2015 AMG S65
On my 2007 SL 55 P030, on the instrument cluster I can select a constant read out for the oil temperature it blinks an oil can symbol (simulating a warning) until it reaches 80 degrees C (after which it goes steady and shows the oil the actual oil temperature inside the engine) and according to the owners manual only than you should step on it.
I use this option almost 99% of the time and I have observed that my water temperature gauge will be in the normal range 80-95 (within 3-4 miles) way before the oil reaches the 80 degree C safe zone (which on average takes 6-10 miles of driving time)
I use this option almost 99% of the time and I have observed that my water temperature gauge will be in the normal range 80-95 (within 3-4 miles) way before the oil reaches the 80 degree C safe zone (which on average takes 6-10 miles of driving time)
