[PeterJohn]

I came down a slightly inclined exit side road coming off a dual carriageway and briefly saw an amber warning message on the driver's display saying "top up coolant". This is for the heat pump.
It happened the next day whilst the car was on the driveway first thing in the morning. I stopped and started the car several times and it stayed on display. I went to the garage to show them, but by the time I arrived there, it had disappeared. They put it on their diagnostic machine, but nothing showed. They took the cap off the coolant tank and released the pressure. The coolant tank level was correct, so they did nothing else. It has not happened since.
This was 10 days ago but haHas anyone else seen this message on their vehicle?

 

[Rav_mav]

They need to bleed the entire coolant. I had mine 2 days ago at Hertford Merc and they mentioned that they received a lot of EQB and EQC with an airlock in the coolant tank causing some gushing sounds as well as popping up the amber warning to top up coolant.
They bled the system and refilled the coolant. Apparently, there was no need to topup the coolant, because the quantity was right, but the airlock was throwing the sensor off.
Hope this helps

 

[PeterJohn]

Thanks for responding. As described the pressure was released and with normal circulation and having a header tank there would not be any need to do anything further as the coolant level remained the same. They are a large dealership in Oxfordshire.

 

[Alsmith]

I came down a slightly inclined exit side road coming off a dual carriageway and briefly saw an amber warning message on the driver's display saying "top up coolant". This is for the heat pump.
It happened the next day whilst the car was on the driveway first thing in the morning. I stopped and started the car several times and it stayed on display. I went to the garage to show them, but by the time I arrived there, it had disappeared. They put it on their diagnostic machine, but nothing showed. They took the cap off the coolant tank and released the pressure. The coolant tank level was correct, so they did nothing else. It has not happened since.
This was 10 days ago but haHas anyone else seen this message on their vehicle?

I have just taken ownership of an EQA & get the message to top up the coolant intermittently. I can only get a slot at the local dealership next Monday!! I thought coolant only related to petrol or Diesel engines?

 

[JakeMC EQC]

I have just taken ownership of an EQA & get the message to top up the coolant intermittently. I can only get a slot at the local dealership next Monday!! I thought coolant only related to petrol or Diesel engines?

Coolant is needed to keep the batteries cool.

 

[hasan.musani]

Our first EQC back in Aug had the top up coolant message appear on the dashboard just 2 weeks of ownership. I’d taken it to our local Mercedes’ dealership and at first they said the same thing you all mentioned about releasing the pressure, anyways that was corrected and within a couple more weeks we had the top up coolant message again. This time Mercedes’ diagnosed the problem relating to a faulty valve. This valve is on a back order and eta is 2 months for the fix. So Mercedes’ decided to replace our car with another new EQC. Taken possession yesterday and guess what! TOP UP COOLANT message on this one too…….

 

[mudlogger]

As I understand Mercedes has at least three different problems wrt coolant that they have needed to solve on the EQA,EQB and EQC; The first was a problem with some batches of coolant that turned into gel and jammed the system, the second was air in the system as mentioned in this thread, and the third is a huge recall in china where they replace seals close to the rear motor. There have been lots of reports of leaks in china, some leaked into the motor, and motor failure... I see also in the forums in Norway that EQ cars leak coolant, so guess this is a systematic problem.

 

[Parkwood]

I have just had this message in a sept 21 delivered car which has been faultless to this point. The message has gone and is not shown in the onboard messages. Coolant is just to the T marker. Am ordering some and will top up a little and see what happens. Will put my garage on notice too. It was a cold morning with a sudden temp drop so maybe something confused the brain. Complex systems not the same as ICE for sure as someone else commented on another thread.

 

[Parkwood]

Had my system topped up they put in about 350ml seemed to think cold weather is common cause of causing the message as the liquid reduces in volume and of course if they fill it to min reqs only at the factory the oddities of parking on slopes etc combined with the reduction in volume can trigger the warnings. we shall see

 

[JarmoRunne]

They need to bleed the entire coolant. I had mine 2 days ago at Hertford Merc and they mentioned that they received a lot of EQB and EQC with an airlock in the coolant tank causing some gushing sounds as well as popping up the amber warning to top up coolant.

What kind of sound is "gushing sound"?

Just drive about 15km to my work with EQC and halfway through the journey, a loud, occasionally stuttering sound appeared from the left front (driver's side). The noise disappeared when accelerating and when stationary.

Under the bonnet there is coolant pump (text: kühlmittelpumpe) approximately where the sound came from.

 

[PeterJohn]

Back to my original opening post of the "Top up coolant" message. I have had several more messages displaying exactly the same thing. I went to one of the largest UK dealerships where I live (Oxford) and they confirm they have had many more instances of this on the EQA, EQB, and also the EQC.
It is now confirmed by Mercedes in the UK that there is a problem with a batch of coolant caps. They (Oxford dealership) had many of them in stock but have now run out with more on order.
It appears there is going to be a recall (UK) of affected cars for cap replacement. Mine is on order against the chassis number.

 

[rgafitanu]

The cap in question has been in use since the nineties starting with the W210. I see that in UK the wait for a part is huge so if you have another MB you can swap the cap to verify. Alternatively you can get one from a junk yard.

 

[PeterJohn]

[QUOTE]rgafitanu
The cap in question has been in use since the nineties starting with the W210. I see that in UK the wait for a part is huge so if you have another MB you can swap the cap to verify. Alternatively, you can get one from a junkyard.[/QUOTE]

Humm. It is a different part number for a BEV. Mine has been on back order and has just arrived at the dealership, so it will be fitted in the near future.

 

[rgafitanu]

Hi Peter John,
Attached is the repair report. The air pocket makes sense if they were able to add 6/10 of a gallon more than they drained. Anyway can you please post the cap part number when you get it?
Thanks.

 

[PeterJohn]

The details of the cap are:
Radiator cap for the high-temperature cooling system.
Part number 2975005100

My error has only appeared 3 times, so I will not be going to have it fitted until 30 March 2023

 

[rgafitanu]

I’m not sure their fix is working. The level is dropping. Maybe it needs a longer drive to turn the level switch on. In any case I will ask them to check with MB UK and get the red cap. Is your March 30 date set in as a result of only 3 occurrences?

 

[PeterJohn]

Is your March 30 date set in as a result of only 3 occurrences?
View attachment 1971

Yes, it was my decision based on being busy with other things. Also, it is only a 30-minute appointment based on the fact that I only live 5 miles away.