I needed some help in finding out if my C220 Thermastat is still working properly. My car is also losing coolant and requires topping up every 10 days. I was wondering if anyone could help give me some tips on figuring out if the thermastat is fine. Where's it located on my car? and is it easy to change? Like the RAD hose that leads to the rad, usually their are pressure filled will coolant, mine can easily be squished and their is little coolant you can usually feel inside. Anyone know what's going on? and where my Thermastat is.

Thanks guys.

Don't take this the wrong way but, based on your description, go to a garage.

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2007 C 230 Sport.

your t-stat is on front of the engine at the opposite end of the top radiator hose. to the right of that plastic black cover with the MB Star molded on it.

With engine cold -sitting over night- start car and feel the top radiator hose, it should stay cold for a few minutes until the t-stat opens and then the hose gets warm - be careful of radiator fan coming on at any time

Do you see where the coolant is leaking? Have you checked and opened your coolant overflow tank to see what color the coolant is? should be yellowish, if it looks like chocolate milk post back here.

Also things like a new overflow tank pressure cap will make a big difference if it has never been changed.

Hey Ethan, thanks for your response. I drove my car from work right now, so I won't be able to test the hose and thermastat opening till later in the day or tommorow morning. However I checked the Resovoir right now, and it seemed very low again for having been filled up 4 days ago. I had the water pump done last year by an indy mechanic...But that's all he did. I tried looking for the thermastat, and couldn't find it right now. If I order a new one, is it easy to change, something I could do myself? Also I sqeezed the rad hose, and it seemed like little coolant sitting in it, easy to squeeze and you hear the coolant inside moving. Under neath the car I don't see any leaks either.

I took a flashlight to the resvoir and i see green coolant at the bottom...not choclate milk. But around the resvoir walls, it seems like someone just drank choclate milk and the sidewalls had dried....Also I think the cap is factory, do you think its seal is broken? Around my engine right now it smells like burning coolant mixed with something...but no leaks...please help, thanks

Hi there trueog,

Thermostat seldom give problem. It will cause the temp to rise to the red zone if it's stuck. However the radiator cap is more likely to cause problem if the rubber seal and spring tensioner fail. Anyway get it replace as it's relatively cheap.

Since you mention you need to top-up coolant every 10 days, I bet the radiator is leaking at the end tanks. The radiator is made from aluminium but the end tanks from plastic. Due to time and heat, the plastic can crack and cause coolant to leak. Inspect carefully as it is quite difficult to see. Happened to my 190E last time. The water pump also can leak at the rubber seal.

The trick is to start observing the suspected area the moment you start the car in the mornings from a cold engine. You will soon see coolant slowly seep out from the leak in a few minutes time just as soon as the thermostat opens.

On my case both the radiator end tank and the water pump leaked at the same time.

Hope this helps.

Cheers.

Thanks. I'm going to try that tommorow morning when the car's cold. Start it up and stand there and watch to see if their's any leaks. On my car its really tough to see the bottom of the radiator. ALso my car after a short fast ride, the temp sits quite high when you're in the city...that's why i was doubting the thermostat.

Thanks