S-Class (W220) 1999-2006: S 320 CDI, S 320, S430, S 500, S 600

overheating

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old May 24, 2025 | 12:08 PM
  #1  
00gtstang's Avatar
Thread Starter
Newbie
 
Joined: May 2025
Posts: 6
Likes: 0
overheating

hello all ...working on a 04 s500. it overheated past 120C. did a coolant flush, new T stat, burped and bled the system. idled just fine. drove 15 miles, hit 120 again. I noticed the heat is not super hot. the fan is working. is the next step a new water pump and another coolant flush ? thanks for any help
Reply
Old May 24, 2025 | 12:49 PM
  #2  
wallyp's Avatar
MBWorld Fanatic!
10 Year Member
Liked
 
Joined: Dec 2012
Posts: 2,473
Likes: 439
From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
First, see if you are actually overheating.An overheated engine feels noticeably hotter - you can feel the heat when you open the hood/bonnet. It will smell hot - usually noticeable. The Mercedes Benz gauges are usually accurate, but you don't want to spend hundreds on unnecessary repairs. Non-contact temperature-measuring guns are pretty cheap.
Amazon Amazon
Reply
Old May 24, 2025 | 07:52 PM
  #3  
00gtstang's Avatar
Thread Starter
Newbie
 
Joined: May 2025
Posts: 6
Likes: 0
Originally Posted by wallyp
First, see if you are actually overheating.An overheated engine feels noticeably hotter - you can feel the heat when you open the hood/bonnet. It will smell hot - usually noticeable. The Mercedes Benz gauges are usually accurate, but you don't want to spend hundreds on unnecessary repairs. Non-contact temperature-measuring guns are pretty cheap.
https://www.amazon.com/Thermometer-B...s%2C106&sr=8-3
yes it is overheating
Reply
Old May 25, 2025 | 01:37 PM
  #4  
waterzap99's Avatar
Senior Member
Photogenic
Liked
Loved
Community Favorite
 
Joined: Jul 2023
Posts: 296
Likes: 91
S550 V8, CL600 V12, SLK32 AMG
I might be totally off, but does this car have a secondary coolant pump?
I had overheating issues, secondary pump was not working. No check engine lights or anything.
Reply
Old May 25, 2025 | 03:44 PM
  #5  
tusabes's Avatar
MBWorld Fanatic!
15 Year Member
Photogenic
Photoriffic
Liked
 
Joined: Jan 2008
Posts: 6,150
Likes: 533
Mercedes
Your radiator fan controller is busted . Common problem . You may see it spinning but it’s a multi speed fan and the controller is not spinning it fast enough
Reply
Old May 25, 2025 | 05:47 PM
  #6  
00gtstang's Avatar
Thread Starter
Newbie
 
Joined: May 2025
Posts: 6
Likes: 0
Originally Posted by tusabes
Your radiator fan controller is busted . Common problem . You may see it spinning but it’s a multi speed fan and the controller is not spinning it fast enough
that would make sense actually.... does the controller come WITH the fan or can you replace separate ??
Reply
Old May 26, 2025 | 10:06 AM
  #7  
Fried Chicken's Avatar
Super Member
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Dec 2007
Posts: 980
Likes: 224
2005 S500 Designo
Originally Posted by 00gtstang
that would make sense actually.... does the controller come WITH the fan or can you replace separate ??
Prepare your *******;

new parts cost a fortune
Reply
Old May 26, 2025 | 12:46 PM
  #8  
00gtstang's Avatar
Thread Starter
Newbie
 
Joined: May 2025
Posts: 6
Likes: 0
how can I test the fan speed ? I do have a bi directional scanner. can I use that to test the speeds ?
Reply
MB World Stories

The Best of Mercedes & AMG

story-0

6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

 Verdad Gallardo
story-1

Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

 Verdad Gallardo
story-2

Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

 Verdad Gallardo
story-3

8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

 Verdad Gallardo
story-4

Flawlessly Restored Mercedes 190E Evo II Heads to Auction

 Verdad Gallardo
story-5

Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

 Verdad Gallardo
story-6

Mercedes EQS Gets A Major Update: Everything You Need to Know

 Verdad Gallardo
story-7

5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

 Verdad Gallardo
story-8

Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

 Verdad Gallardo
story-9

10 Most Reliable Mercedes-Benz Models You Can Buy Used

 Verdad Gallardo
Old May 28, 2025 | 10:48 AM
  #9  
e350forme's Avatar
Super Member
5 Year Member
Photogenic
Liked
Community Favorite
 
Joined: Jun 2018
Posts: 533
Likes: 39
From: Northern Hemisphere - Chicago
fleet
Originally Posted by 00gtstang
how can I test the fan speed ? I do have a bi directional scanner. can I use that to test the speeds ?
time to drive to the yard and ****** all you can and then worry about removing any faults


Reply
Old May 28, 2025 | 12:02 PM
  #10  
OldManAndHisCar's Avatar
MBWorld Fanatic!
Community Builder
Community Influencer
Liked
Loved
 
Joined: Jun 2021
Posts: 3,110
Likes: 1,346
From: Fleriduh
W212 E63S Wagon - GSL580 - E63 - E350 - C300
My issue.....the pump wheel had moved on the shaft of the water pump. It moved far inboard of where it is supposed to sit. Seems very odd to me - that was the cause.





Reply
Old May 28, 2025 | 12:20 PM
  #11  
00gtstang's Avatar
Thread Starter
Newbie
 
Joined: May 2025
Posts: 6
Likes: 0
Originally Posted by OldManAndHisCar
My issue.....the pump wheel had moved on the shaft of the water pump. It moved far inboard of where it is supposed to sit. Seems very odd to me - that was the cause.
was it overheating while driving only ? it's just weird it never went over 85-90 while idling. then driving it, starts ticking upward. it hit 120c.
Reply
Old May 28, 2025 | 12:26 PM
  #12  
OldManAndHisCar's Avatar
MBWorld Fanatic!
Community Builder
Community Influencer
Liked
Loved
 
Joined: Jun 2021
Posts: 3,110
Likes: 1,346
From: Fleriduh
W212 E63S Wagon - GSL580 - E63 - E350 - C300
Originally Posted by 00gtstang
was it overheating while driving only ? it's just weird it never went over 85-90 while idling. then driving it, starts ticking upward. it hit 120c.

Went through a few variations. I think while the impeller was moving inboard. The impeller is fully confined by the pump housing - as compared to being fully outbound of the impeller housing. To me, very odd. But, if not driving, temps were normal idle temps.





Reply
Old May 28, 2025 | 12:38 PM
  #13  
00gtstang's Avatar
Thread Starter
Newbie
 
Joined: May 2025
Posts: 6
Likes: 0
Originally Posted by OldManAndHisCar
Went through a few variations. I think while the impeller was moving inboard. The impeller is fully confined by the pump housing - as compared to being fully outbound of the impeller housing. To me, very odd. But, if not driving, temps were normal idle temps.
I think I will give the water pump a shot. the car has 200k miles lol.
Reply
Old May 29, 2025 | 01:59 PM
  #14  
tusabes's Avatar
MBWorld Fanatic!
15 Year Member
Photogenic
Photoriffic
Liked
 
Joined: Jan 2008
Posts: 6,150
Likes: 533
Mercedes
Originally Posted by 00gtstang
that would make sense actually.... does the controller come WITH the fan or can you replace separate ??
you can replace separate but all Chinese parts are garbage

its better to get used original Mercedes fan controller from
junkyard or eBay and those are usually sold with the fan. It’s not your water pump it’s the fan Controller

Last edited by tusabes; May 29, 2025 at 02:02 PM.
Reply
Old May 30, 2025 | 11:55 AM
  #15  
waterzap99's Avatar
Senior Member
Photogenic
Liked
Loved
Community Favorite
 
Joined: Jul 2023
Posts: 296
Likes: 91
S550 V8, CL600 V12, SLK32 AMG
I once used Benzninja with the STAR software to check my fan. Had overheating issues with other car.
He was able to spin up the fan through the software and it sounded like a helicopter taking off. Fan was fine in my case.
If you can get the software you will 100% know if the fan isnt spinning fast enough.
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 10:05 PM.

story-0
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-1
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-2
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-3
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-4
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-5
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-6
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-7
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-8
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
story-9
10 Most Reliable Mercedes-Benz Models You Can Buy Used

Slideshow: From bulletproof sedans to surprisingly tough SUVs, these Mercedes models proved that the three-pointed star can go the distance.

By Verdad Gallardo | 2026-04-08 09:55:49


VIEW MORE