mJstk01

Recently my radiator fluid level light has been coming on and off whenever I drive around. It comes on spontaneously. I checked the level of antifreeze and added a little more. The light still comes on and off. Any ideas??? I was thinking maybe I should flush out the entire radiator and put in new antifreeze. The Slk230 is a 98 with 21,000 miles on it.

Thanks in advance...

mbtech208

This is a common problem with the SLK. You need to replace your coolant level sensor and the washer fluid level sensor. Both of these sensors share a common circuit, and if either one fails, you may get a warning light for the opposite sensor.

CopperDesigno

Is this something any one with the mechanical ability could do? My coolant light comes on and off right now, the temp gauge tells me all is good, but I still hate lights popping on. If this is something relaively easy, where coule I find the directions to replace the sensor(s)? Thanks

sandrogrima

I had the same problem...or at least a similar problem. My light would come on occasionally, then go off. A few days later it would come on again.

took it to the dealer. They said that based on the sensor desing (float, at least on a 2002) if the fluid is not topped up to the top, the float moves around and gets stuck in a position that falsely indicates low levels. They simply added more coolant to force the float to the top at all times and the problem disappeared. That was over 8 months ago, no problems since. Hope tis helps!

CopperDesigno

It ended up being a fan control module on the same circuit as the Low coolant level sensor. The dealer told me that all of the cooling systems bits are on the same circuit and things aren't right, it flashes the light.

snglbrd

Mine went on after a flush. I then topped up fluid, the float wasn't at the top so i popped it with my finger it then floated, and light went out. Looks like the sensor is sensitive.

yellowslk

Same thing happened to my slk too. All you have to do is top it off.

DickB

Ditto.

black98slk230

Wow, this has been happening to my slk too. All I have to do is top it off!??!?!?! Can I just use regular antifreeze or is there some special $$$$ antifreeze for mercs like everything else?

DickB

Well, as long as you don't need to add lots (so it won't get diluted) and assuming the antifreze mixture is close to 50/50 to begin with, you can just top it off with distilled water. That's what I did.

pfphipps

Although hinted at, I do not believe anyone has said to make sure you add water to the windshield washer as well. The light will come on if either the radiator level or the windshield washer are low on fluid. I know, it makes no sense but that is the way it is at least on earlier SLK230s. My radiator sensor was replaced three times under warranty before they figured it out. Try adding to the windshield washer and see what happens.

black98slk230

Well, I tried both things, adding cooland and washer fluid, but light still turns on and off at random times. Looks like its the temp sensor. Thanks anyways, guys.