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So I first got this alert the day after a Service A. SA said "....sometimes after coolant repairs- air pockets get in the lines. so we would just need to bleed it and top off with some coolant. would only take about 5 mins...." but the alert stopped and I never went back. I only drive the vehicle on weekends and lately the alert comes back, but only on the first cold start of the day. I have some MB coolant; is there a "fill level" that's plainly evident and idiot-proof?
I started another thread this morning but this seems to have more comments. I also have the same issue but only when the car is cold, the message goes away after 30 seconds. Does anyone know what type of coolant I can use to top it off? It's a pinkish/orange color.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
I am experiencing the same thing for the first time on my 2015 SL400 and was wondering, "What the heck?" It has been cold (20°-45°F) when this happens, but on inspection, the fluid lever is normal. After a minute or so, the message goes off and there is no stored message. I have not had any services performed that may cause this. I may ask the service manager at the dealership, but of course, they will want to check things out. I'm going to scan for stored DTCs and will post back here.
I started another thread this morning but this seems to have more comments. I also have the same issue but only when the car is cold, the message goes away after 30 seconds. Does anyone know what type of coolant I can use to top it off? It's a pinkish/orange color.
While you decide which coolant to use, and If it is missing just a bit, I would use "distilled water". It should not be an issue. If it starts missing again, then you can start tracing the leak somewhere.
G40 coolant is the pink stuff spec'd for a '15 SL400 per FCPEuro.com.. Zerex makes it. Either get the premix (costs more/gallon) or mix it 50/50 with DISTILLED water.
I'd not add distilled water only to top it up, but I live in an area where it gets cold enough to be of concern to me. I need the freeze protection offered by 50/50. https://www.fcpeuro.com/products/mer...s-mer-q1030005
Want more info? https://blog.fcpeuro.com/how-to-pick...NzMwLjU4LjAuMA..
Last edited by rapidoxidation; Dec 21, 2023 at 04:24 PM.
G40 coolant is the pink stuff spec'd for a '15 SL400 per FCPEuro.com.. Zerex makes it. Either get the premix (costs more/gallon) or mix it 50/50 with DISTILLED water.
I'd not add distilled water only to top it up, but I live in an area where it gets cold enough to be of concern to me. I need the freeze protection offered by 50/50.
Fair. Weather-dependent, and I am down south. Likely the same amount of water outdoors, frozen up north, and water vapor down here
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Took another look and, low and behold, we have two reservoirs! Whoda thunk that? And, in the one that has the level sensor, the coolant level is actually low.
While you decide which coolant to use, and If it is missing just a bit, I would use "distilled water". It should not be an issue. If it starts missing again, then you can start tracing the leak somewhere.
Please do not use plain tap water either.
I bought some Zerex g40 and topped it off. Light has not come on since.
Took another look and, low and behold, we have two reservoirs! Whoda thunk that? And, in the one that has the level sensor, the coolant level is actually low.
I have a 2019 GLE400 (which is also W166 and I think is very similar or the same these older M-class models, actually the very end of the W166).
In your photo, how do you know the coolant level is low? I only see a unlabeled white level bar on the outside of the main coolant tank, but I don't know if that indicates a low level marker or full level marker. Is there really some kind of full marker inside the tank as I've read here that I can see only when I take off the cap?
As others have reported here, I am getting Low Coolant warning when the car is turned on each morning, and it goes away after some driving and stays off the rest of the day. However, coolant expansion tanks both seem full even before the morning first starting, if I am reading the white line correctly as a minimum level indicator
The MB diagnostic code for this error is in SAM module as P25567B, but unfortunately that code doesn't tell me anything different besides the what the instrument cluster is saying --- Low Coolant Level!
From what I've read here, there is no coolant level sensor of any kind in the secondary expansion tank (and the error always relates to the primary expansion tank only)? For my model, I also can't seem to find any coolant level sensor on either expansion tank, nor in the parts diagram. How can the car know the coolant level without a sensor there?
I have a 2019 GLE400 (which is also W166 and I think is very similar or the same these older M-class models, actually the very end of the W166).
In your photo, how do you know the coolant level is low? I only see a unlabeled white level bar on the outside of the main coolant tank, but I don't know if that indicates a low level marker or full level marker. Is there really some kind of full marker inside the tank as I've read here that I can see only when I take off the cap?
As others have reported here, I am getting Low Coolant warning when the car is turned on each morning, and it goes away after some driving and stays off the rest of the day. However, coolant expansion tanks both seem full even before the morning first starting, if I am reading the white line correctly as a minimum level indicator
The MB diagnostic code for this error is in SAM module as P25567B, but unfortunately that code doesn't tell me anything different besides the what the instrument cluster is saying --- Low Coolant Level!
From what I've read here, there is no coolant level sensor of any kind in the secondary expansion tank (and the error always relates to the primary expansion tank only)? For my model, I also can't seem to find any coolant level sensor on either expansion tank, nor in the parts diagram. How can the car know the coolant level without a sensor there?
Park the car on a level surface and let it cool down completely. Slowly open the reservoir cap and look inside. Coolant should be just below the black line.
Yes, upon realization that coolant needs to be up to the black for the tank to be considered full, and that the white bar on the outside of the coolant expansion tank is actually a MIN level marker, I added more coolant and the indicator instantly went off!
Took another look and, low and behold, we have two reservoirs! Whoda thunk that? And, in the one that has the level sensor, the coolant level is actually low.
mine looks different than yours but also a bit low, and likely the reason the alert has returned with the cold weather.
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