S-Class (W126) 1979-1991: 300 SE, 300 SEL, 380 SE, 380 SEL, 420 SEL, 500 SEL, 560 SEL, 360 SEC, 500 SEC, 580 SEC, 300 SD TURBODIESEL, 300 SDL TURBO, 350 SD TURBO, 350 SDL TURBO

coolant getting low ! 560

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old Jul 6, 2008 | 12:41 PM
  #1  
560er's Avatar
Thread Starter
Newbie
 
Joined: Aug 2006
Posts: 6
Likes: 0
coolant getting low ! 560

Hi all

I have 1990 560 euro spec, my problem in short is it loses coolant while running, if in town after around 3 to 5 day's the low coolant light pops up. on high way maybe after 100km (around 60 miles)

i've changed the following:

1- resrve tank cap
2- radiotor
3- thermostat 60c (it's hot around here )
4- water pump

aux fan and fan clutch are ok.


i've filled the radiotor and left the cap open then ran the car and waited to warm up i've notice that the coolant is going up after some time and kept getting up!!

maybe there is a presure biulding up some where ?

one mechanic told me that i need to change the head gasket, but there is no white smoke, no water with oil.
the coolant is getting out throw the cap because i notice the coolant around that area on firewall.

the car is running smothly and accelation is good


should I change the head gasket or am I missing something?

thanks in advance.
Reply
Old Jul 12, 2008 | 11:16 AM
  #2  
DrB300SE's Avatar
Newbie
 
Joined: Jul 2008
Posts: 1
Likes: 0
From: St Petersburg, FL
1989 300SE
I'm in the middle of changing out my water pump (89 300SE). I used a bottle of UV Liquid ($6 US at parts store) and a standard black light bulb to locate the leak.
Try it, it's easier than guessing.
Reply
Old Oct 16, 2009 | 10:48 PM
  #3  
daniel_pvq's Avatar
Newbie
 
Joined: Oct 2009
Posts: 1
Likes: 0
560sec 300e
coolant leak

i found the coolant leak on mine (86 560sec euro) in the heater valve solenoid diaphragm. right next to the batery. very easy to take apart and replace that diaphragm.
Reply
Old Oct 17, 2009 | 09:31 PM
  #4  
Berde's Avatar
Member
 
Joined: Jan 2009
Posts: 105
Likes: 0
From: Atlanta, GA
1987 300 SDL
If the UV light does not show anything, then it could be an internal loss. But, before you replace the head gasket, check the radiator pressure. It should keep around 14 PSI when engine not running. Then, run the engine and if it is well pass that then you have compression from the cylinders getting into the cooling system, which is typical of head problems (gasket damage or cracked head). Not always when an issue with the head arises there is water in your oild or visversa. When the thing escalates to that then usually the car will overheat in a matter of hours and will gulp mounstruos amounts of coolant. Snap-on tools makes a very good Cooling system pressure check with diferent adapters to conform to different size necks openings. Hope is just a heater hose gone bad, which is not serious and an easy fix and that my comments show you some light! G.L. with the fix Bud
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 06:49 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