chuck57

Last week I got a "Check Engine Coolant" message/alert displayed briefly after starting the car in the morning (engine as cold as it ever gets in Hawaii). After engine warmed the display cleared, engine temp normal and no indication of a problem throughout the day. Debated simply adding a little water, but decided to go with the MB recommended spec no. 325 (P/N Q1 03 0002) Anti-Corrosion/Antifreeze Agent from the local dealer for ~$38/gal.

It took about 0.8 quarts of fluid to bring the level just above the full (cool) tab in the surge tank.

Now I'm just wondering if its common to lose minor amounts of coolant over time? I've had the car 1.5 years, driven 75/25 city/highway) and 13,000 miles; one "A" service completed last December.

I did a search of the forums and the net and it didn't seem to be a common issue...

desired_speeds

Its normal to need a very small amount of coolant over time. Even if the car isn't leaking.

Jason B

Ah. So it looks like I'm a little low:

Also do I need a special kind if I just need to top off?

DaveW68

You need to get the coolant up to the top of that plastic piece. Use the same color MB coolant that is in the car to top it off. The dealer sells a couple different kinds with different colors.

Jason B

So you have to use "Mercedes coolant"? It's down probably only a half a cup, needs topped off. My guy at dealer said I could just put a little distilled water in

Bamzilla

I was under the impression that the coolant is a concentrate and you are supposed to mix it with distilled water at a certain ratio before adding. Anyone know what that ratio is?

DaveW68

It's a straight fill from what I understand. No mixing. Although I'm sure a little distilled water to top it off is fine.

mercedesbenzs55

These days most coolant is premixed. If it DOES need mixing its 50/50.

If your coolant is premixed it WILL say "Premixed 50/50" on the bottle.

mercedesbenzs55

You can mix it with prestone or and equivalent coolant. The little bit of "green" coolant your adding in to top it off isn't going to affect the ratio.

Its about $1.99 for a gallon.

Sundeck19

2012 S550 w/ 74k . . . had to add coolant twice in past month. No evidence of leaks, just dash notification to "Check coolant level" . . . . thankfully the Dealer tops off at no cost!

Thnx Schumacher Just wondering what issues may lay ahead ?? thnx All

justinmorrison

A while back I had a similar situation and it turned out the coolant was leaking into the washer fluid reservoir through the heating coil. No evidence of a leak since my washer fluid level was low at the time, so the reservoir was just filling up (unknown to me). You might want to take a look at that possibility.

Anthony1624

how did you fix it? Can you help me? Any videos on YouTube?