Driving 70s and saw this in 5mins. Stays there consistently.

Coolant? The temp gauge stays at red 120F.

 

I'd check the coolant level after the engine cools off

 

Checked coolant this morning. Does seem low. Dealer trip or something I can order myself and top up?

 

If it's under warranty, I'd take it in and let them check it out. Just in case their is a leak.

 

So I took the car to the dealer last week, as I didnt see this problem ever again, but still took it in to take a look.

Visual inspection of the coolant level looked OK, they topped it off, no codes show up in tests, no leaks nothing.

2 days later, I am on a freeway, and doing 60-65, all is fine. Go into left lane to overtake a car, and go into 70-75, and the temp goes hot again, AND this time also shows the Coolant Hot, Please Shut down the Engine warning, and within 10sec or less, I am on the shoulder, engine off.

Towed to the dealership, so far nothing looks wrong, car will be there to troubleshoot and a possible ride on the freeway again by the techs. Again, coolant is topped off, no codes etc show up in diagnostics.

EDIT: No obvious overheat smell or anything in/around the car when on shoulder or driving.

Thoughts?

 

Did they check the thermostat - open/close ?

 

Not sure. All I got was most of the things looked OK...no codes etc.

 

Probably should look into a faulty Coolant Temperature Sensor.

 

Thanks for mentioning that also. I hope they know what all could go wrong and I will mention these things once I talk to them tomorrow.

I assume, its something that is not activating at right time leading to the warning.

 

Did you get video???

 

No Video, was driving at 70s and had to immediately get to shoulder and stop the engine.

But, the tech was able to reproduce the scenario on freeway and the coolant pump control level is now found to be stuck and not operating. Waiting for time to fix etc.


Thanks!

 

At least the tech was able to reproduce.

 

Got the car back, coolant pump was replaced (under warranty). Have done some runs on interstate (75mph) for about 20 mins, no more overheating.

The coolant gauge sits at about "7" or "8" of those progress boxes in the gauge. Not sure if that is the normal operating temperature for C300s.

 

That's where mine sits.

 

Did anyone else face this issue ? This happened with my C300 today morning (07/23/2017) as soon as I hit 70 mph on the Interstate highway. The road shoulder was narrow (due to some on going work) and I could not pull over for about a mile. Took an exit and called Mercedes Roadside assistance. They said I will not get a loaner vehicle since it is Sunday. So I cancelled my trip and waited till the engine cooled off. Came back home taking some back roads. The temperature remained at around 80% on my way back and while doing 50 to 55 mph. Need to take it to the dealer tomorrow. Coolant level is normal. Is this a common issue with W205 ?

 

Off topic, but how do you get the Km/h to show in your display?

 

I always thought that it is the default setting. From the pics, the OP has it in his car. So do I ! Mine is a 2015 C300 Base with Premium Package.

 

anecdotal experience with C300 4Matic:

Yesterday, I had to drop off my C400 for a sunroof repair (little piece of plastic broke, entire assembly needs to be replaced... ) and they gave me a C300 loaner - brand new 2017 w/very few miles on it.

I get home, change, leave and head towards the park for my evening walk. Car gets 10 minutes from home and overheats. Like, boiling coolant spraying over the ground. Nasty overheating situation.

I let it cool down, limp it back to the dealer (only a few miles away), and get yet another 2017 C300 as a consolation prize.

So that's my experience with overheating. I have put 43k miles on a C400 over the last 2.5 years - never seen the temp gauge move past the first tick right of 80. And it is running the DINAN piggyback in Race mode.

 

I am yet to take it to the dealer. They do not have a loaner available. It is perplexing to know that this is happening with other W205s as well.

@l3it3r

Just to let you know. I already replaced my sunroof twice. Once, the sunroof got stuck while being operated and the sunroof was left open permanently. Luckily it was not raining. The next time the screen (that thin piece of cloth) sagged and the sunroof got stuck again. This time it was permanently closed for a change.

For the past 1 month, I have had irritating rattles from the sunroof fixture. I am sure they will have to remove it and assemble it again to fix that. God save me after I run out of warranty.

 

I hope it's not going to be a widespread problem with C300's...

 

I went to close mine one day and it went a couple inches, and then went back to the open position, like it was stuck on something. A small piece of plastic had broken off the assembly. It would still open and close, but it made horrible noises, so I immediately stopped using it and took it to the dealer - they ordered the parts like 2 months ago, I dropped it off two days ago.. If the car rattles any more than I've had to deal with (5-6 times in the service bay for rattles) after this, I'm definitely moving on. That Porsche has been calling my name anyway

 

Yeah, the famous "no codes" BS.
Here's the issue with that argument: In order to throw a code, the manufacturer had to have the forethought to anticipate that specific measurement, combination of measurements or issue as being out of spec and program the car to respond by doing XX or YY. There's NO possible way MB could predict every single thing that could go wrong with the car.

That being said [or typed], if they said there's no codes, I would change to a different dealer. There HAS to be a coolant warning or an overheat warning stored that would generate a code. Anything that appears in the instrument panel is also stored as either a temp fault or a permanent fault.

Personally, I don't like getting 1/2 the story from the dealer, but i would push this.

Hopefully you have pictures or a video of the issue from the display.... I ALWAYS take an immediate picture of any "warnings" from the car so the dealer can't respond with "there's nothing wrong"....

 

Update on the overheating issue (to help others who may have similar problems). I got my car back today. As expected, water pump was replaced. I will be driving the car on the Interstate today evening. Will report any issues if present.

 

Happened to my wife's car this morning on her way to work. Guess the pump has a 4 year shelf life

 

Hi, could you let me know if you happened to know the part number of the water pump that was replaced please? Thank you.