EnDLeSs_27

I have a 02 c230k, and for some reason I dont think the radiator fan starts to run when the car begins to get hot. I had the fan replaced last year by an aftermarket depo one since the genuine Mercedes one were 4x the price. But does anyone know if it s a depo problem? Or anything else? I dont think it is a coolant problem because that was just flushed by the dealer and there are no leaks anywhere in the car since the dealer examined it.

My car slowly raises in temperature to the point where the message "Stop car and turn off engine" in red comes up.

Is my fan bad? Any suggestions on how to fix this overheating issue?

samaritrey

that sounds like a bad thermostat or water pump unless it is really hot where you are and you are not moving at all

phister

Can be thermo, water pump, fan switch, or fan relay.

ND2020

Or even software. Not 100% positive, but I had my car tuned and my fan was doing the same thing. Took it to the dealer and they were able to get it functioning properly again by updating the software.

SunnyRayToronto

What's the temperature that's being displayed just before the red "Stop car and turn off engine" message is displayed?

Thermostat should open at around 87 to 90 Celsius and even then cooling fan may not kick in. That message should kick in when car is about to overheat,... something like about 120 Celsius,.... or when the front SAM gets too many conflicting or unexpected signals from sensors and assume the worst, so it wants you to reset.

It could also be a faulty coolant temperature sensor.

Are any fault codes being returned via OBD2 scantool?

EnDLeSs_27

No fault codes. It goes up to 120C then the message pops up. I am in chicago. It is usually anywhere from 70-90F here.

SunnyRayToronto

Yeah,... about 120 C is the trigger for that red light "Stop car and turn off engine" message. Don't even wait for the message, if it gets to about 100-110C you should look for a spot to rest the car. The high temperature can damage the engine and gaskets that separate engine oil and coolant.

The thermostat should automatically open at around 87-90C,.... it doesn't seem to be so I'd change that first along with the coolant (50/50 Zerex G-05 last 5 years or 150,000 miles) if it hasn't been done recently.

What are you using to try to pull the OBD2 Scan codes?

What's the mileage?

Does radiator fan kick in when you turn on AC?

EnDLeSs_27

The car is at ~60,000 miles.

I turned the AC all the way up and the fan does not turn on at all. I thought the problem was from my aftermarket DEPO fan. So I got a brand new Mercedes fan installed and it doesn't seem to turn on at all.

I also checked fuse 51 as that corresponds to "engine fan" and the fuse is fine.

EnDLeSs_27

Is there anyway that I can test to see if it is a bad thermostat or water pump? Rather then just changing them out 1 by 1.

Russell Ormerod

yes, run the engine and feel the top and bottom radiator hoses, if they at the same temp the thermostat has opened.

EnDLeSs_27

Turned out to be an electrical issue. The wiring in the connector to the fan was messed up causing it to short. Therefore, the fan would never get a signal from the car to start running.

It was actually an easy fix. Just fixed the wiring.

samaritrey

Good to here it was all sorted out. Where was the short I have not heard of this ever on the W203's

babybluebenz

I would also like to know, thanks!
just finished my t-stat and it keeps cool..also 105+ F outside
..but then it hits the RED message bat/alt ..seems to go limp mode after ..then i get no juice to stuff blinkers, fan, radio, ac etc.. (?)
with no fan it goes to 100 quickly..all hoses feel XXtra HOT (bad rad?)
it has a new battery new cam magnet new CPS new T-stat/fluids
it was a great 10 minute drive
and should the green emergency release button in the trunk always be blinking/ON?\
thanks!

King Z

I have a similar issue if not the same. Which wire are you referring to? Can you be more specific? Cause I left my car today and the mechanic is going to try to figure out what is causing the short. If you can help that would be great!

EnDLeSs_27

The MB technician showed me the wiring that was messed up after I had them diagnose the problem.

Basically the fan connector had 4 wires. Two fat ones and two thinner ones. The MB technician said one of the thinner wires was not getting a signal from the Cars computer to let the fan know it should turn on. He said it was loose in the connector, and somewhere else it was cut/disconnected/something. Cant remember exactly what he said.

So basically he said he was going to run a completely new wire all the way to the cars computer to replace the faulty one.

It should be noted that my car was involved in a front end car accident over a year ago which I am assuming was the cause of the wiring for the fan to even get missed up in the first place. (although the fan was working fine until recently, I am assuming it had to be loose and not properly fixed from the accident)

So if you're experiencing similar problems. Make sure all the wires in the connector are getting some sort of power or signal. If they are then the problem is your fan. If not follow the faulty wire and replace it.