Mercedes W124 Coolant Temperature Sensor Testing 4 Pin

Just testing the 4 pin coolant sensor, its responsible for sending the ECU computer info and ignition system.
Mine checks out OK , to do a better test you can remove sensor and put it in hot / cold water, but pay attention to get it to exact temperature target value.

[@TheReal1953]

John....from BW?! I'm gonna do this in a pot with the sensor suspended and use a candy thermometer. Previously, nobody seems to say how far off in Ohms the sensor can be. I have three sensors to play with. Thanks for finding the real data on the sensor limits!

[@mygermancars7264]

Right, if it’s in the ballpark should be fine, if it’s way off replace

[@ofnicisab]

Thank you for the video. It was very useful for me

[@johnashley9021]

Hi, First keep the vids coming you are a real trooper at fault finding
I have a quick question I have a 300ce with the 103 engine. Running temp is fine but when I stop the engine the cooling fan never comes on and with it been hot here the engine starts to cook. I guess the fan should stay on until the temp drops ??
Thanks

[@artbyleclerc3329]

If you’re talking about front auxiliary fans, they only come on with air conditioning on.
Or if engine goes above 105c, never when engine is off.
The main engine cooling fan activates or locks up when driving and engine RPM above 3K.
I think it’s not a good system for hot climates, if fan would lock up at 600RPM while idling it would cool engine a lot better.

[@marcusfinanger1116]

My fans stay on no matter what I do or what temp. Could this be because of a faulty temp sensors? The on with blue pins?

[@mygermancars7264]

Yeah, had a 91 300E and the bad 2 pin sensor did that.

[@marcusfinanger1116]

@@mygermancars7264 i have an 260e 1991

[@user-rk6vh6ps6p]

Thank

[@jcritter9295]

I just bought a 1990 300e. Sat for 6 years. Replaced the water pump. It runs good at first start but after less than a minute. It idles rough. Plugs get fouled and looks to be too much fuel. What can it be?

[@mygermancars7264]

Fuel or electrical related , first make sure all tuneup parts are good, check distributor parts are good, if it’s the m103 engine check duty cycle, could be a lot of testing stuff.

[@bongsiukim9151]

Hello sir, i am a w124 300E enthusiast, can i get a workshop manual from U 🙏

[@mygermancars7264]

All I have is this. www.w124performance.com/service/Index/103index.html

[@dikranberg7600]

❤❤❤❤❤❤❤ ok

[@belisioglipet4655]

That sensor is $15 bucks, just replace it and save your self the time and trouble of testing...