FrankL

Hello,
The 2007 c230 sport is overheating but the needle on the gauge does not go to the red marker on the gauge but I am getting the thermometer graphic on the dash display which I assume is indicating that the vehicle is overheating.
the temp on the gauge does jump up slightly and then goes down slightly at times. The other interesting thing is that the AC does not work. I wonder if the two are related.
So I'd like to diagnose radiator fans, coolant temp sensor or any other component such as the thermostat.
Can someone tell me where the temp sensor is located, at front or rear of engine, which side?? I have a W203.
Thanks in advance for viewing and helping.

Steve.O

I am also having the exact same issue and I have a 2006. Seems to have come on all of a sudden. I have checked the power before and after the harness at the bottom of the radiator fan and I have power. No fuses are blown (51 or 54). No CE codes popping up, just the dash warning like you have and the temp needle jumping up and then back down again when it gets up just over the 80 mark. I watch the coolant temp with my OBDii scanner and it doesn't jump around at all. So I am not sure why it would do that and why the fan just won't come on. And the A/C seems to try to kick on but I don't think it is. And then once that needle jumps up and the alert pops up, then the air instantly goes warm. I unplugged the temp sensor which is located at the back of the driver(left) side head. You have to either get to it from underneath or if you have small hands you can reach it from the top once the air filter cowling is removed. I had to go from underneath to be able to disconnect it, but then to test it I could pull the harness from the top. I thought that if I unplugged it the fan would automatically go to the default setting on high, but nothing happened. There are two sensors there, the one on top is the temp sensor. There is also a sensor at the thermostat that I tried unplugging and still nothing. But I have read on other posts here that it is likely the fan assembly. I ordered one and will install it hopefully before Monday and I will let you know if it worked.

I haven't figured out how to bench test the fan since there is a signal wire on top of the two power wires and the ignition wire. Any help would be greatly appreciated.

RogelioChandle

It's crucial to address the overheating and AC issues promptly. Check coolant levels, radiator fans, thermostat, and AC components. If unsure, consult a mechanic for a thorough diagnosis and repair. I was talking to a grad student yesterday, and she told me about a great article called ‘7 Best US Essay Writing Websites for Graduates’ on NewsDirect you will find essay writers world article called ‘The Ultimate Guide to Writing Essays for Graduates.’ It’s a game changer for students because it doesn’t just list services, it goes deep into the strengths of each platform. If you’re a grad student looking for high-quality essay writing services, then this article is for you. It makes it easy to decide which service is best for you.

Steve.O

UPDATE: Installed new fan this weekend and we are back in business.

FrankL

I did the same thing and replaced the fan and things also went back to normal. The thermostat didn’t appear to be stuck closed since the vehicle wasn’t overheating. I used a temp gun and the temp was close to the analog gauge in the car.
When I ran the car while doing all the checking, the fan never came on. Once the new fan was installed, the AC began to work also.
From what I learned the fan is brushless and has a control module on the shroud. But it must operate based on computer command
As for the temp sensors, I never got anyone to confirm the temp sensor location on my 2007 C230. Someone mentioned there is no temp sensor at the rear of the engine so I just went with that information and assumed the sensor on the thermostat housing was ok since the analog gauge appeared to be working.
replacing the fan was a guess and a bit of process of elimination based on what I assumed was working. If anyone has a procedure for testing a temp sensor, that would be helpful.
The following items were considered when looking at the system: thermostat, fan and module, temp sensor, gauge, and ecm. It’s quite a system just to control the engine temp.

Steve.O

There is in fact two sensors; one in the thermostat housing and another one at the back of the head.