anant369

I have a '98 Slk230 and was wondering what the coolant level should be at when it is cold. Like up to what line or area in the tank. Also if there is too much where does it overflow when it heats up?

rghinzel

I wouldn't worry about the level. They way the cooling system is designed, you basically fill it up until the ball float in the radiator system prevents further fluid going in. I had my vehicle serviced by MB which included a cooling system flush. After driving it for about two days the radiator low level light went on. I added coolant as described above (It took about a litre) and has been fine since. Any excess bleeds out via the over flow line onto the ground. In my case the MB techs failed to bleed the air out of the system. When the system settled it needed the additional fluid.

Brian_R170

rghinzel is correct. You basically fill it all the way up. The overflow tank itself is pressurized. In theory, it's a sealed system and no coolant should ever escape, but there's an overflow that will allow coolant to escape directly onto the ground if needed.

The coolant light came on in my '99 once when it was about a year old. I added maybe 8 to 10 ounces of distilled water and it the light went out. It never came on again afterward in the 18 months or so before I traded the car. Several other people had the exact same thing happen. The coolant level sensor is fairly sensitive. The sensor is also prone to indicate low coolant when there isn't a problem. The reason is that they sensor is tied into the same circuit as the windshield washer fluid reservoir and if one sensor goes bad, it can report a problem for the wrong fluid.