VahidBaboli

I'm hoping this is the correct forum for my issue.
I own a 2014 S550 Edition 1 with 90,000 miles. Recently, I've been getting a low coolant level warning on the dashboard roughly once a week, even if I drive less than 50 miles. On one occasion, the temperature gauge read 200°F, whereas it normally reads 190°F.
After I top off the coolant, the warning disappears until the following week. There are no signs of coolant leakage on my driveway. The car seems to run well without any smoke or power loss.
My mechanic suggests it could be the head gaskets. Shouldn't there be visible smoke or steam from the exhaust if that's the case? What else might be the problem?
Additionally, the fan starts at full speed in the early morning when I just open the door. When the engine is off but still warm, the fan runs for 10-15 seconds every five minutes until it stops about an hour later.
Thank you.

DaveW68

My old 2013 GL550 used to occasionally get the low coolant warning, at which point I would top it off and it was fine for a while. If you haven't done it in the last 30k miles, you may want to consider having a full coolant flush done with a new thermostat. That may fix the issue. BTW, my car always hits 200 degrees when it's fully warmed up and pretty much stays right there until I shut it down.

VahidBaboli

Never flushed the coolant, I will see if I can do it myself or will have my mechanic to do it. I have always seen 190, that is why I was afraid when I saw 200.
Thanks for your reply.

Katie22

Did you check your oil to see if its milky? Your engine might have a water to oil cooler that is leaking water into the oil. Here is a picture example of what these coolers look like. http://shop.advanceautoparts.com/p/d...E&gclsrc=aw.ds


Its been a while BUT if i recall one way to test for a leak is to borrow a coolant pressure tester at the auto parts store. Add pressure to the coolant system and see if it holds.


Katie

VahidBaboli

I can only check the oil with the dip stick and seems ok to me, not milky. The link you sent takes me to auto part shop.

MBNUT1

What about turbo cooling lines?

Katie22

Yes the link was supposed to show an example of an oil cooler you would find similar on you engine,

Mitch Alsup

I had a similar problem over the last year.

It turns out that, in MB great desire for luxury everything, that they designed a coolant line into the windshield washer reservoir (WWR), and than nine had "gone bad".

So, take a look at the WWR, and at the oil, too. If you see a color other than WW fluid, suspect that warming line has "decayed"

VahidBaboli

don't know where that is but will look into it.

VahidBaboli

Why would they warmup the windshield washer fluid, it won't freeze anyway. Also, wouldn't that cause the windshield washer fluid overflow from its tank? I will check.

DaveW68

It's not the same as the windshield washer fluid. Our wipers have the wiper fluid come directly out of the wiper blades through the tiny holes. In the winter, those could plug up. Having a heater line going through the washer pump helps ensure that the holes won't clog with icy fluid.

95Sinned420

Unless you have special winter type washer fluids, they do freeze in freezing temps.

VahidBaboli

My E350 does not have that heater (or is hidden?) and I haven't had any freezing problem, I use -20' rating coolant for our area in New Jersey US.
The coolant is green and the windshield fluid is also light green, hard to say if they are mixing, maybe I use red windshield washer fluid and check.