W212 (almost) overheating
Thread Starter
Junior Member
Joined: Jul 2011
Posts: 54
Likes: 1
2005 C55 AMG; 2000 CLK320 Cabriolet, 2000 C230 Kompressor & 2001 ML430
W212 (almost) overheating
Just got my w212 running again, had serpentine belt break and took me a while to get to it, also did the the oil filter gaskets to prevent it from happening again
now it started to run hot.
before would rarely hear the fan turn on.
now it turn on around 35mph, the temperature will stay steady around 90c. Once I hit 45-50mph the temperature creeps up a bit and will fluctuate. Over 50mph it will
go up, sometimes hitting right before the red mark, it has never hit the red that I have seen that’s why I say it’s almost overheating, and will stay there, and sometimes it will go down a bit and sometimes down to normalish.
checked coolant, checked hoses, checked radiator, all looks normal
no codes, I’m using an autel mk808s, also have a Mercedes star but it’s put away right now
any suggestions?
I have about 155k miles and had the Mercedes fix done about 18 months ago. Car was sitting around 6 months with the serpentine belt out.
thank you for any advice or suggestions
now it started to run hot.
before would rarely hear the fan turn on.
now it turn on around 35mph, the temperature will stay steady around 90c. Once I hit 45-50mph the temperature creeps up a bit and will fluctuate. Over 50mph it will
go up, sometimes hitting right before the red mark, it has never hit the red that I have seen that’s why I say it’s almost overheating, and will stay there, and sometimes it will go down a bit and sometimes down to normalish.
checked coolant, checked hoses, checked radiator, all looks normal
no codes, I’m using an autel mk808s, also have a Mercedes star but it’s put away right now
any suggestions?
I have about 155k miles and had the Mercedes fix done about 18 months ago. Car was sitting around 6 months with the serpentine belt out.
thank you for any advice or suggestions
MBWorld Fanatic!
Joined: Jan 2009
Posts: 9,224
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From: V E G A S
1922 Ford Model T / no OBD
Giving engine temperatures without ambient temperatures is senseless.
90C seems pretty normal for diesel engine and fluctuation above indicate thermostat working.
Maybe your thermostat is acting a bit, so replacing it would be next step.
90C seems pretty normal for diesel engine and fluctuation above indicate thermostat working.
Maybe your thermostat is acting a bit, so replacing it would be next step.
Thread Starter
Junior Member
Joined: Jul 2011
Posts: 54
Likes: 1
2005 C55 AMG; 2000 CLK320 Cabriolet, 2000 C230 Kompressor & 2001 ML430
Temperatures have been around 50f here, around 90 is not the issue, going all the way up just shy of the redline is what my concern is
MBWorld Fanatic!
Joined: Jan 2009
Posts: 9,224
Likes: 1,798
From: V E G A S
1922 Ford Model T / no OBD
You should get real temperature scanner to troubleshoot issue like that.
There is no way broken belt can affect future cooling, so track what else happen to the car between?
What color is the coolant?
Knowing what engine you have would help as well.
As a "Mercedes fix" do you mean AEM ?
There is no way broken belt can affect future cooling, so track what else happen to the car between?
What color is the coolant?
Knowing what engine you have would help as well.
As a "Mercedes fix" do you mean AEM ?
MBWorld Fanatic!
Joined: Jun 2021
Posts: 1,919
Likes: 522
From: New Hampsha
'17 GLS450, '14 GLK250, Grandpa's Roadster
Did the car overheat when the belt broke? If it did, you should replace the thermostat. Once they get pushed outside their comfort zone they often become unreliable.
Last edited by John CC; Feb 3, 2024 at 09:50 AM. Reason: typo
Thread Starter
Junior Member
Joined: Jul 2011
Posts: 54
Likes: 1
2005 C55 AMG; 2000 CLK320 Cabriolet, 2000 C230 Kompressor & 2001 ML430
I think I figured it out,
checked the fluid levels again, they where ok and the cap did release pressure when removed. Put cap back
on and started to take the plastic
stuff off the radiator fan off, and did a double check on
the cap and it needed a little
extra turn, maybe it was slight loose?
Continued to remove the stuff on the radiator fan, pull on the fan and it’s loose, slides in and out easily, check and see what’s good on, and the slot on the radiator that the tab from
the fan goes into is bent, so it’s not grabbing. Straighten it out, make sure the fan goes in it this time, now you Jaír can’t pull the fan out.
Reassemble, go for a drive on the freeway and it’s back to normal.
could have been a loose cap or the radiator fan having some play or both, idk but now this works.
Now if could get the MAF and Egr to cooperate without taking to the dealer it would be great
checked the fluid levels again, they where ok and the cap did release pressure when removed. Put cap back
on and started to take the plastic
stuff off the radiator fan off, and did a double check on
the cap and it needed a little
extra turn, maybe it was slight loose?
Continued to remove the stuff on the radiator fan, pull on the fan and it’s loose, slides in and out easily, check and see what’s good on, and the slot on the radiator that the tab from
the fan goes into is bent, so it’s not grabbing. Straighten it out, make sure the fan goes in it this time, now you Jaír can’t pull the fan out.
Reassemble, go for a drive on the freeway and it’s back to normal.
could have been a loose cap or the radiator fan having some play or both, idk but now this works.
Now if could get the MAF and Egr to cooperate without taking to the dealer it would be great
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