rondocap

So I put some Mercedes Anti-freeze about 2 weeks ago, and it was filled to the top. (To the rubber lining where it is recommended.)

I opened up the radiator cap to check where the level was, and it had gone down about half an inch or so.

Is this normal? Does some of it evaporate? I see some white residue on my radiator tank area too. It's been very cold lately, so I am not sure if that causes it to act differently.

Or do I possibly have a minor leak?

DRTYLNDY

The level could be different if the temperatures were different. The antifreeze should not evaporate at all. If the level keeps going down it is a leak. I would keep a close eye on it maybe it was just a temperature difference from the start.

BVLDARI

also, check your auxilary tank or whateve it is called. it may have pushed the fluid there which is normal. there should be an indicator there showing your how much fluid you should have.

IngenereAMG

In short....... level should not drop.

nick 55

The coolant system by it's nature will allow some water to evaporate when the car is cool. Also, the coolant/water mix will expand a little as the engine heats it up, so if the car was warm, not even hot, it will be a little bit lower when the car is cold. I would clean off the white residue(MB coolant leaves white residue) and make sure the coolant cap is securely tightened. I have seen some reservoirs leak at the cap. I have seen many cars require a top off of coolant of half a quart when in for an A or B service. No leaks, just evaporation.

Nick

rondocap

I think I figured it out - when I topped it off last, I accidently put slightly more above the maximum point - therefore when the car heat up, the pressure caused some of that liquid to seep in under the cap, when it expanded - so I think that is what caused the loss since then it would cool down to a lower level.

I have the fluid at the recommended level now, and have not had the problem repeated.

patrat

that's what happening to mine as well when I last topped coolant to black top part of the reservoir before morning cold start/cold coolant. So what's correct recommended level then?

rondocap

I would try putting it slightly lower than that, to give it some space. I saw that putting it up to the black part of the reservoir would cause this to happen, so a little lower and it's fine.

patrat

thx! I was just going off what owner's manual said to top till black part when cold coolant at morning starts, but that's cause these overspills then.

rondocap

I took a look in the reservoir with an LED flashlight, and I saw a black looking knob inside - I think that may actually be the indication for the maximum limit, and it's just a bit lower than the bottom of the black top. Maybe that's what the manual meant?