Hey guys, I just picked up a 2014 C300 with only 5k miles on it. Looks like I am having an overheating issue:

Everything was going fine until yesterday I noticed the temp gauge climbing past 90C and all the way into the red zone past 120C. I didn't receive any messages or lights in the dash. I immediately pulled over and popped the hood. I noticed the radiator fan was not spinning. I kept the hood open, turned off the car, and let it cool for 15 minutes. I turned the car back on and the fan turned on and the temp returned to 90C.

I thought everything was ok. I came home and checked the coolant level and noticed it was a little low so I added some more. I let the car cool overnight.

This morning I turned the car on and noticed the fan working correctly. I drove it around town for a bit. On my latest trip I set the AC to the coldest, and noticed the air wasn't that cold. This is when I got concerned. While driving home I noticed the temp rising rapidly again. It went to the red zone and the car became really sluggish, I pulled over on a side street. I didn't receive any messages or lights in the dash. I popped the hood and noticed the fan wasn't running again. I let the car cool for 15 minutes. I started the car, the temp was at 120C and the fan kicked on for about 30 seconds full blast and dropped the temp to 90C. The fan turned off. Then I noticed the temp rising back up to 120C and the fan didn't turn back on. I turned the car off again. I went through that procedure twice more until the third time when the fan remained on. I quickly drove home to post this.

So the fan seems to be functional. It just isn't turning on when required or is very intermittent. Do you think it could be a temp sensor or fan relay issue?

I apologize for the long post, I just wanted to give as much detail as possible. Any tips/advice is greatly appreciated!!

You are under warranty....just bring it to the dealer to have them fix it

On a current model-year car with low mileage, the warranty clearly applies. From your timeline, this happened during business hours. Why not just drive to the dealer today, rather than ask us to guess long-distance tonight?

Sorry guys, forgot to mention that this car has a rebuilt title. My father in law did the rebuild. I don't think the warranty applies. I will take it to the dealership tomorrow anyhow, was just hoping to get an idea of what the issue may be exactly.

A salvaged title on a 2014 with 5k. How mangled was that thing when you picked it up and how much did you get it for ?

Car was in good shape to be honest. The guy hit a meridian on the highway. Only had to change bumper. Hood had a small crack in the front. Headlights and radiator weren't damaged. Thing is, the air bags deployed in the dash. My father in law works on alot of luxury cars and said that when the air bags deploy in a car like this they usually write it off since to replace the bags and dash can be expensive since there are quite a few bags on this vehicle.

I did a CarFax on it. The guy leased it from a local Mercedes dealership and only drove it for 4 months. I'm thinking the dealership pulled some strings to get it written off since they don't want to be reselling an "accident" vehicle on their lot.

I'm thinking maybe during impact the temperature sensor got knocked loose or lost its seal. Maybe that is causing the erratic readings? I don't know.

I have the same thing happening to my 2010 C300. I changed the fan and still same thing. Help?

If it happens while you're driving, and I realize it's uncomfortable in the summer, but put your heater to the highest setting and let it go full blast. That doesn't mean you can drive 200 miles with it to your destination, but if you can't stop immediately, it'll buy you a little bit of time.

Thanks, ya that works good, I have already been doing that, but I want to fix it

Could it be as simple as the thermostat needing to be replaced? I don't know, just throwing that out there.

I'm thinking im going to try that next

MB thermostats fail open.

I'd call a convenient Mercedes dealer, give the service department your VIN number and ask what warranty coverage you have.

Keep us posted.