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Folks, there's a silly engineering oversight in the EQB that causes the chambers of the coolant reservoirs to become unbalanced, and as a result a caution message is presented on the dash.
I've had this message occur twice now in the first 500 miles of ownership and while it's extremely easy to fix, it's not something that an owner of a brand new vehicle should have to deal with. But the fix is VERY easy, as there is no missing or leaking coolant.
EQB - Nuisance Message "Check Coolant Level"
When you open the hood you'll notice this appearance of the coolant reservoir. Note that there are two chambers, each with a black cap, and the fluid level is unbalanced and below the fill line on the left chamber. This low level causes the caution message.
Unbalanced coolant causing error message
To fix the issue, simply carefully and slowly loosen the left cap (on the side with the lower level) until it vents. You will hear the air hiss when it occurs. Then repeat on the other cap. After less than 30 seconds the fluid levels with balance on both sides and you can tighten both caps again. When the fluid levels are balanced the left reservoir will again contain enough fluid to sit above the fill line and eliminate the caution message.
Balanced coolant after venting
Reportedly, there's a recall in some markets to replace one of the black caps on the coolant tank with a modified red cap with a vent but our new 2023 EQB in the USA was delivered with the black cap. I'll check with my dealer when I have a chance, but this fix will keep the EQB happy in the interim.
Folks, there's a silly engineering oversight in the EQB that causes the chambers of the coolant reservoirs to become unbalanced, and as a result a caution message is presented on the dash.
I've had this message occur twice now in the first 500 miles of ownership and while it's extremely easy to fix, it's not something that an owner of a brand new vehicle should have to deal with. But the fix is VERY easy, as there is no missing or leaking coolant.
EQB - Nuisance Message "Check Coolant Level"
When you open the hood you'll notice this appearance of the coolant reservoir. Note that there are two chambers, each with a black cap, and the fluid level is unbalanced and below the fill line on the left chamber. This low level causes the caution message.
Unbalanced coolant causing error message
To fix the issue, simply carefully and slowly loosen the left cap (on the side with the lower level) until it vents. You will hear the air hiss when it occurs. Then repeat on the other cap. After less than 30 seconds the fluid levels with balance on both sides and you can tighten both caps again. When the fluid levels are balanced the left reservoir will again contain enough fluid to sit above the fill line and eliminate the caution message.
Balanced coolant after venting
Reportedly, there's a recall in some markets to replace one of the black caps on the coolant tank with a modified red cap with a vent but our new 2023 EQB in the USA was delivered with the black cap. I'll check with my dealer when I have a chance, but this fix will keep the EQB happy in the interim.
mine arrived in Baltimore on 2/27. No reply from my sales guy yet but I will keep all posted. I will ask about this and inspect upon delivery
It happens every 200-300 miles after relieving the pressure. I even swapped the cap with the one from my SL, they are the same part number. I am dropping it off at the dealer next week. There is an EQ forum from Europe where this issue is discussed more, apparently more EQs in Europe than here.
FWIW, I spoke with the service director at my dealer this week and he was aware of the issue due to other EQBs in his shop and he had independently verified with MBUSA that the car will also need the new RED reservoir cap (with an internal vent) when our car is serviced. There's currently not a recall so the only way to get the ball rolling is top bring our EQB into the shop and document the issue. They have not been simply issued new caps to distribute so everything must be don the hard way (for now.). I'll take the car in next week to start the process.
Last edited by cadetdrivr; 03-11-2023 at 11:44 AM.
This happened to me this weekend. I noticed one side of the reservoir was low while the other was high. I opened the low side cap fully and as soon as I loosened the high side some coolant came out but for the most part the it went into the other side of the tank and leveled out.
Open the low side and leave it open for 30 minutes if you can. And go to the dealership and raise hell.
BTW even with their flush and bleed the left side is going low and as soon as I get the message I’m going back to the dealer.
I’ve been discussing with a gentleman from UK on the EQ forum and they are receiving a “Red Cap for high temperature system” PN 297 500 51 00. The moment I get the message again I will ask them to just get the cap.
Last edited by gafitanu; 03-14-2023 at 10:43 AM.
Reason: Add stuff
All I can say is that I hope that my car which is currently slated for a second-decade June build has the red cap and the problem will be solved. At least I have a very responsive dealer and service manager who will pound on MBUSA if he gets a runaround.
Dealer ordered the correct red cap for me on Wednesday and it arrived this morning. I picked it up in my C300, took it home and installed in on my cold EQB 350. Problem fixed with minimal hassle.
I am not so lucky. The service director looked up the bulletin and told me it is for another stored code not the P25567B that I had. There was no logic that I could bring in the discussion especially for something that costs the dealer probably $5. Any body has a copy or print of the bulletin?
I am not so lucky. The service director looked up the bulletin and told me it is for another stored code not the P25567B that I had. There was no logic that I could bring in the discussion especially for something that costs the dealer probably $5. Any body has a copy or print of the bulletin?
Sorry to hear that, if it is too much hassle I would consider buying the cap yourself and call it a day.
Similar issues but I do see leakages down below with pink liquid
Mine EQB 300 is 4 months old and about 3,000 miles so far. I had the similar experiences that every time after a long trip (> 200 miles or so), I got this “coolant level low” message.
I had been to dealership twice, they just top it up for me. Now this weekend was the 3rd time, and I could see clearly leakage down below with wet areas and with some pink water marks.
terrible…attached photos here. Hope MBUSA could do something for just replacing with a red cap for all of us!
Mine EQB 300 is 4 months old and about 3,000 miles so far. I had the similar experiences that every time after a long trip (> 200 miles or so), I got this “coolant level low” message.
I had been to dealership twice, they just top it up for me. Now this weekend was the 3rd time, and I could see clearly leakage down below with wet areas and with some pink water marks.
terrible…attached photos here. Hope MBUSA could do something for just replacing with a red cap for all of us!
not good especially how coolant is sweet and animals and pets love it, but it is toxic at the same time.
Noticed a problem starting with my prior 2013 Smart Fortwo and now the EQB250+. If you see condensation on the top of the reservoir I suspect it’s because they are being filled with too much water/not enough coolant concentration. This causes the coolant to boil and seep out the cap pressure relief. My solution was to add pure concentrated G40 (pink) coolant.
I also filled both reservoirs maybe 5/8 to 2/3 from the level line to the top (cold) after sitting overnight. BUT now when I start with opening the smaller reservoir coolant bleeds out. (Two mornings in a row now). Is the system not properly bled of air, (my suspicion)? And why is there pressure in the morning cold? This high level seems to have stabilized the level of the larger reservoir but not the smaller one….
Hi,
I have an EQB that came already fitted with the red cap here in the UK but is still doing the same thing. It’s only 3 mths old so not sure what’s going on.
I took a look at my coolant tank yesterday--looked okay. I'm wondering though...does everyone else's metal parts look like this under their hood? I've not seen this sort of white cakey stuff on auto parts before.In the photo, I cleaned off the right side of the top of the part, just for comparison.
I thought of salt, but nothing else around the white cakey stuff covered parts have similar coating. I guess I'll clean it up and see if it comes back. General observation from looking in the engine bay...not sure how well this will hold up over time...so many electrical connections/parts seemingly slightly open to the elements. Normally an engine would have blocked the former GLB from getting spray/gunk up from below to the many electrical connectors on top of an engine, but it looks like in an EQB some spray could make it past the undercarriage to critical part areas. We'll see shortly once it snows here in Iowa. At least the connectors won't be experiencing severe heat cycles like with a conventional engine, which makes the plastic connector housings as brittle as a stale cookie over time.
The white cakey stuff as people like to refer to it as is called "corrosion" caused by normal atmospheric conditions when alloys warm up and cool down with water droplets forming during the warming up and cooling down process.. It is nothing unusual and happens on the majority of vehicles somewhere on some parts.
So I made the newbie mistake on this today by loosening the right cap (black) first because the coolant level was unbalanced in the two reservoirs and coolant started to spray out. Immediately tightened it back and slowly loosened the left one (red one). This helped the excess pressure vent out. and got the coolant levels balanced out in the two reservoirs. So a key learning is that even the red reservoir only vents after a specific pressure has been exceeded and one can have unbalanced coolant levels even when you have the new red vented cap (Part #297-500-51-00) fitted. I chose to manually vent the excess pressure and balance the coolant levels as I have a long drive tomorrow. Left (Red) is the one that needs to be loosened to vent the pressure.
White stuff I’m pretty sure is silicate from the coolant. Be sure you tighten both caps fully, there’s a slight resistance immediately prior to fully closed. I am still with both black caps, but the larger reservoir coolant became opaque/cloudy. Bringing it in Wednesday for diagnosis/coolant change hopefully…
03-02-2023, 02:29 PM
