S-Class (W140) 1991-1999: 300 SD, S 350TD, 300 SE 2.8, S280, 300 SE 3.2, 300 SEL 3.2, S320, S320L, 400 SE, S420, 400 SEL, S420L, 500 SE, S500, 500 SEL, S500L, 600 SE, S600, 600 SEL, S600L, 500 SEC, 600 SEC

Engine Temperature

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old Jun 13, 2009 | 01:35 AM
  #1  
Merc_Trouble's Avatar
Thread Starter
Newbie
 
Joined: Jun 2009
Posts: 3
Likes: 0
1998 W140 S320
Engine Temperature

Hi,

I recently found out a new trick (new to me) to find out the exact engine temperature, however I'm starting to question its reliability.

On the A/C press and hold "REST" button for TEN seconds.
The A/C display will suddenly show two numbers, one number on the left side of the display, and the other on the right.
The one on the left, corresponds to some function( 1,2,3,..6 etc,) so by pressing on the Auto button SIX times, it will show the number SIX on the left, and that corresponds to engine temperature.


Now, on a different note, I was wondering if anyone can help me regarding normal engine temperature. (On the regular gauge, not using the REST method).
Usually my gauge when driving around with the A/C on, is slightly below the division between the 80 and 120. (Naturally it looks like 100 °C to me, but I was told that it's actually 90°C).
My vehicle is a S320 1998 and I live in Saudi Arabia where it's pretty hot this time of year. But it's always reading around that level when I'm driving, should I be concerned ?


Thanks
Reply
Old Jun 13, 2009 | 12:07 PM
  #2  
PorscheTech911's Avatar
Newbie
 
Joined: Jun 2009
Posts: 1
Likes: 0
From: Chicago, IL
93 600SEL
Just my opinion, but most all vehicles run at that temperature so I believe that your car is fine.
Reply
Old Jun 13, 2009 | 05:06 PM
  #3  
stox's Avatar
Member
 
Joined: Nov 2004
Posts: 92
Likes: 0
'95 S500C, '96 C36, '86 190E, '72 280SEL
You're fine. The system/engine is designed to run at that temperature. As for the REST button, that is the diagnostic mode that can tell you all sorts of interesting information. Here is a writeup on it: http://www.babcox.com/editorial/ic/ic40142.htm
Reply
Old Aug 12, 2011 | 02:32 PM
  #4  
oldsinner111's Avatar
MBWorld Fanatic!
 
Joined: Jun 2010
Posts: 1,246
Likes: 52
From: tennessee
s320
I run a lower thermostat so my temp is just under 80c.
Reply

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 


You have already rated this thread Rating: Thread Rating: 0 votes,  average.


All times are GMT -4. The time now is 07:06 PM.

story-0
New Electric Mercedes-AMG GT 4-Door Coupe Unveiled: 10 Things You Need to Know

Slideshow: Mercedes-AMG's new electric GT 4-Door Coupe trades combustion for software, synthetic noise, and more than 1,100 horsepower.

By Verdad Gallardo | 2026-05-20 20:08:15


VIEW MORE
story-1
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

Slideshow: Not every Mercedes design becomes timeless, some feel stuck in the era they came from.

By Verdad Gallardo | 2026-05-12 18:09:07


VIEW MORE
story-2
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

Slideshow: Yes, Mercedes built manual cars, and some of them are far more interesting than you'd expect.

By Verdad Gallardo | 2026-05-02 12:36:58


VIEW MORE
story-3
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.

By Verdad Gallardo | 2026-04-29 11:19:28


VIEW MORE
story-4
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

Slideshow: Before curves took over, Mercedes mastered the art of the straight line, and some of those shapes still look right today.

By Verdad Gallardo | 2026-04-25 12:05:49


VIEW MORE
story-5
Flawlessly Restored Mercedes 190E Evo II Heads to Auction

Slideshow: The 190E Evolution II shows how a homologation necessity became a six-figure collector icon.

By Verdad Gallardo | 2026-04-22 17:53:47


VIEW MORE
story-6
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

Slideshow: Mercedes is turning one of its core nameplates electric, and the details show just how serious this shift is.

By Verdad Gallardo | 2026-04-21 13:58:06


VIEW MORE
story-7
Mercedes EQS Gets A Major Update: Everything You Need to Know

Slideshow: Faster charging, longer range, and a controversial steer-by-wire system define the latest evolution of Mercedes-Benz EQS.

By Verdad Gallardo | 2026-04-15 10:35:34


VIEW MORE
story-8
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

Slideshow: These overlooked Mercedes-Benz models never got the spotlight, but they quietly delivered more than most remember.

By Verdad Gallardo | 2026-04-13 19:35:45


VIEW MORE
story-9
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

Slideshow: A well-used 1991 Mercedes-Benz 300D with more than one million miles is now looking for a new owner, and it still appears ready for more.

By Verdad Gallardo | 2026-04-10 10:05:15


VIEW MORE