Can i drive with engine overcooling?
Thread Starter
Newbie
Joined: Dec 2018
Posts: 14
Likes: 0
2011 C300 4matic sport
I want to sell you something, I truly do but your car seems to be operating normally. These fluctuations are normal, additionally if you are stopped in traffic and turn on the heat please keep in mind that you are literally extracting the heat from the coolant to warm the cabin and this is why the temp drops slightly. This is similar to the approach you would take if your car was overheating and you needed to limp it home, you would turn on the heat using your heater core to pull heat out of the coolant and into the cabin.
--Kyle.
--Kyle.
Thanks
Senior Member
Joined: Nov 2013
Posts: 428
Likes: 63
From: Auburn, GA
C250 2013
With similar problem and symptom it took the temp gauge needle 25/30 min of hwy driving in the morning in GA winter to get to the 90 degree mark with the auto heat on.
After new t-stat and coolant it's operating seems to be all good.
I know exactly what Kyle is saying.
I had been having this since last winter but last month it has gotten worse.
So, I think your t-stat is on it's way out.
After new t-stat and coolant it's operating seems to be all good.
I know exactly what Kyle is saying.
I had been having this since last winter but last month it has gotten worse.
So, I think your t-stat is on it's way out.
Thread Starter
Newbie
Joined: Dec 2018
Posts: 14
Likes: 0
2011 C300 4matic sport
With similar problem and symptom it took the temp gauge needle 25/30 min of hwy driving in the morning in GA winter to get to the 90 degree mark with the auto heat on.
After new t-stat and coolant it's operating seems to be all good.
I know exactly what Kyle is saying.
I had been having this since last winter but last month it has gotten worse.
So, I think your t-stat is on it's way out.
After new t-stat and coolant it's operating seems to be all good.
I know exactly what Kyle is saying.
I had been having this since last winter but last month it has gotten worse.
So, I think your t-stat is on it's way out.
Member
Joined: Aug 2016
Posts: 130
Likes: 18
'11 E350 4Matic Sport
Pretty much every modern MB has an electronically controlled/assisted thermostat that can and will vary coolant temperatures. These aren't thermostats of old that have a fixed temperature so small fluctuations from ~85-90 C are to be expected depending on the then current conditions. Below is an article that explains these thermostats and the benefits vs the old fixed thermostats.
The temp fluctuations you posted are in line with what I witnessed in my '09 C300 and my '11 E350.
Electronically controlled thermostat
The temp fluctuations you posted are in line with what I witnessed in my '09 C300 and my '11 E350.
Electronically controlled thermostat
Senior Member
Joined: Nov 2013
Posts: 428
Likes: 63
From: Auburn, GA
C250 2013
Thank you for your experience. You've been driving with your faulty thermostat for a whole year? Whats the reasoning you haven't changed/replaced it, and have you ever gotten a check engine light? I live in NY so the winters here aren't a joke either. Do you think i should continue driving with this thermostat until i get a check engine light?
Super Member
Joined: Nov 2016
Posts: 680
Likes: 152
2008 C350 Sport 4Matic Swap
Guys, if your engine is taking for ever to warm up, change your thermostats. It's very bad running a car cold for a long time, specially during winter since the fuel mixture is staying rich, not only hurting your fuel economy but worse, washing the oil on the cylinder walls and diluting the oil, resulting in premature wear.
Super Member
Joined: Nov 2016
Posts: 680
Likes: 152
2008 C350 Sport 4Matic Swap
Pretty much every modern MB has an electronically controlled/assisted thermostat that can and will vary coolant temperatures. These aren't thermostats of old that have a fixed temperature so small fluctuations from ~85-90 C are to be expected depending on the then current conditions. Below is an article that explains these thermostats and the benefits vs the old fixed thermostats.
The temp fluctuations you posted are in line with what I witnessed in my '09 C300 and my '11 E350.
Electronically controlled thermostat
The temp fluctuations you posted are in line with what I witnessed in my '09 C300 and my '11 E350.
Electronically controlled thermostat
Informative link, thanks for sharing.
Thread Starter
Newbie
Joined: Dec 2018
Posts: 14
Likes: 0
2011 C300 4matic sport
Hello everyone, my car finally popped a P0128 code Coolant Thermostat (coolant temp below thermostat regulating temperature), proving what most of us suspected. Ordered a new thermostat, plan on getting the work done next week.
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