[EQA-S.oz]

For the first time yesterday I noticed a rattling noise in my EQA250, when stationary. The first time I heard it was at a shopping centre carpark and I thought it was coming from some other source, but then I heard it again soon after parking it in my garage after arriving home. This morning I noticed it when I simply approached the car (without the key) and it seems to occur at random, like the other buzzing / whirring noises which seem to be part of EQA normality.

However, I think this noise is abnormal. It is a fairly high pitched, rapid tapping noise which sounds a bit like an impact wrench or when you reach the torque setting on an electric drill and it is coming from somewhere near the front of the 'engine' bay. I haven't heard it whilst driving and I haven't received any error messages or seen any warning lights.

It may be coincidental, but yesterday was our first taste of warm weather (low to mid 30 degree Celsius).

I wonder if others have experienced something like this. In any event, I plan to contact my dealer today to arrange a workshop inspection. (My car has travelled about 5,500km.)

 

[EQA-S.oz]

I have a bit more information on this issue, although I haven't yet visited the dealer.

Part of the information is in very rough video form, which has given me the following sequence...

My car has been standing in the garage for most of the day. When I open the driver's door, it seems to put the car into a form of alert and the EQ display illuminates on the dashboard. A short while later I hear a click from near the fuse box and about 2 seconds after that the electric coolant pump activates. (The pump is located about half way between the fuse box and the 12v battery - but lower in the 'engine' bay.) About 11-12 seconds later the sharp rattle mentioned in my first post occurs. Its duration is about 2 seconds.

I am not sure whether the sharp rattle (the worrying bit) is related to another noise: if I put a stethoscope on the housing attached to the 'radiator' just below the top hose in the image below - and I squeeze the coolant hose - I can hear something - which sounds like a float, as it makes a couple of sounds after I have squeezed the hose and I wonder whether whatever causes that sound is the same thing that 'rattles'. It's as if the mechanical rattle which the car generates is caused by the rapid cycling of a magnetic field, the frequency of the rattle being similar to bullets being fired from a high speed automatic rifle, or machine gun.

A further thought: could my experience be related to the coolant issues discussed in other recent threads on this Forum?

Although I haven't had any 'low coolant' notifications, I believe my coolant level is a bit low. I can't determine from the Owner's Manual what the correct level of coolant looks like. Also, my coolant reservoir seems to have a 'main reservoir' and a smaller one alongside. The level in the smaller reservoir is a bit lower than in the main reservoir.

 

[EQA-S.oz]

I should have mentioned that the sharp rattle seems to come from somewhere just behind the front number plate.

 

[EQA-S.oz]

The source of this noise has now been determined. The EQA250 has a pair of 4-slat shutters located behind the lower grille. The shutters are opened and closed by an electric actuator. The actuator on my car closes the shutters quietly and smoothly, but once open, it fails to close the shutters - and produces the noise I've described. I suspect the teeth on gears in the mechanism may have been stripped. The question is: what caused this?

I can close the shutters by carefully moving the actuating mechanism by hand, but in the meantime, once the shutters are open, each time the system triggers the 'close shutters' sequence, nothing happens apart from the noise.

Our dealer has undertaken to investigate this further next week. Hopefully, there's no need for new parts, but I would be surprised if that proves to be the case. It will then be a matter of how quickly replacement parts can be sourced.

 

[FDR]

I had a look at the area in my car and I can see the parts you’ describing, the only thing I can think of that would cause accidental damage here would be if an object like a twig or something similar had got past the lower grille and then jammed the shutters, otherwise I’d have to suspect a flaw in the operating system. Hope you get it fixed soon, (without having to take out a bank loan to pay for parts!!)

 

[EQA-S.oz]

I agree with your suspicion - about a twig, or similar object - FDR: that something jammed the shutters at some stage, although I also agree that there could simply be a flaw of some sort in the operating system. A variation on the latter theme is the possibility that the shutters are binding in the fully open position such that a simple realignment will remedy the problem.

I should add a little more detail to my post #4: yesterday, the dealer's mechanic undertook a quick inspection of the car and upon hearing the noise, made the 'faulty shutter system' diagnosis. He said he didn't believe there was any reason not to drive the car and a workshop booking was made for next week. (By the way, the mechanic said the EQA250 has 5 coolant pumps - not one, or possibly the two which I had spotted!).

Curiosity got the better of me and after driving the car home, I raised the front on stands and removed the front section of 'engine bay' undertray and the two spats in front of each front tyre. Removing the relatively narrow front undertray revealed a more flexible 'airseal' (of sorts) which, when removed, gave a good view of the shutters and the actuator. Nothing - like the twig or similar item we've speculated upon - dropped out when these undertrays were removed, so I'm more inclined to think there's an operational flaw of some sort.

As mentioned in post #4, I was able to (gently/carefully) manually move the shutters to the closed position and when I triggered the shutter activation process (by opening the driver's door), the system opened the shutters smoothly and quietly. Upon a subsequent trigger, the shutters remained fully open and the rattly noise persisted for about 2 seconds.

I am concerned about a potentially flawed system: this reminds me of my 2002 C240 which suffered 5 air conditioning vent failures in my six years of ownership (from new). (I purchased extended warranty after the first couple of failures!) I was told that the flaw in that system was that the vents were adjusted by plastic gears controlled by electric actuators, the motors of which were too strong for the gears. One would hope that Benz's design capability and quality control had improved since then.

There has been no discussion about who will cover the cost of resolving this current issue, but I'm working on the assumption that it's a warranty job.

In closing this post, I would be interested to know whether - on a car with a shutter system in good condition - the shutters:
(a) 'rest' in the closed position; or
(b) 'rest' in a position (somewhere between open and closed) depending on the battery temperature; and
(c) regularly perform the sequence I described in post #2 above: click from a switch near the battery, coolant pump activated, shutters activated.

I hope this topic is of interest to EQA owners. Now, being more aware of the specific problem, I would change the thread title, but I don't know whether that's possible. An "intermittent mechanical rattle" is a somewhat non-descript title!

 

[FDR]

I just had another quick look at the slats on my car and they’re sitting in the open position, I unlocked the car, which turned on the EQ display and resulted in whirring pump type noises, opening the door and switching on the start button produced more whirring and clicking but none of these actions caused any change in the position of the slats. There’s no rattling noise to indicate even an attempt at movement and I’m wondering if my slats are non functional for some reason. I would have expected the coolant temperature being below working temperature should have meant the slats would be shut, only opening when the temperature went up to allow more airflow to the radiator.

 

[EQA-S.oz]

Thank you for sharing your observations, FDR. I agree; I'd have expected the shutters to be closed while the car - or more specifically, the battery - is cold, but maybe they only close in really cold conditions or, as you say, perhaps they're static in some cars. Having said that, one wonders why shutters would be fitted if they don't also have an active

opening/closing actuator. The image above shows the actuator fitted to my car (photo taken with the front undertray removed). In this shot (one frame taken from a video), the shutters are closed, but in the next frame or two the shutters begin to open and within a few seconds they're fully open (image below) - and there they stay, accompanied by the rattling noise whenever the shutter movement sequence is subsequently triggered. (I closed the shutters manually by gently pushing upwards on the top cross-connecting piece of the actuating frame (i.e. the connector roughly adjacent to the top shutter slats). That manual movement was slowed by internal resistance and a whirring noise - as if gears were being rotated).

I wonder whether anyone can identify what type of actuator this is? Thinking about it a bit more, the rattling noise sounds like an electric solenoid triggered by an electric current which opens and closes in rapid succession. In this case it persists for about 2 seconds on any one occasion. I hope the dealer's workshop has the knowledge and motivation to give me more information in due course!

 

[dBC]

Potentially the same as in the GLA?

Mercedes-Benz OE - Mercedes GLA250 2021 Cooling - Components on Radiator Support


I hate to keep throwing EQC observations into your EQA threads, but I figure the designs are pretty similar so might be relevant. My EQC shutters seem to be always closed. I think the only time I've noticed them open was when I was DC rapid charging on a hot day, with the aircon on. In that case it had the front fans roaring. Of course, I don't know what state they're in while driving but I'm guessing mostly closed. I think their aim is to improve aerodynamics. I guess air being deflected around the car is less of an obstruction than air getting into the engine compartment.

 

[FDR]

I’ll need to take the undertray off and have a closer look tomorrow,going by your pics it looks like a linear actuator, there are various types of operation, some work by rotating a ”nut” to push and pull a threaded rod, others can use a rack and pinion operation they could be susceptible to gear teeth stripping if overloaded. I had a bale wrapper once which used a linear actuator to cut the wrap and it would rattle like you describe when it came to the end of its stroke but came to no harm.

 

[EQA-S.oz]

I don't have a problem with EQC input, dBC. I agree, it's likely that similar design principles are used in the two EV siblings. Interesting that your EQC shutters seem to be 'normally closed', whereas those on FDR's EQA seem to be 'normally open'.

To minimise the chances of damage to the low front bumper on my wife's AMG-line-equipped B250, I've fitted a reversing camera behind the front number plate, which she activates - by momentary push button switch - every time she 'front-end parks' to ensure she stops with a minimal gap whilst avoiding obstacles, such as kerbs.

A similar (temporary) arrangement in the EQA could be one way of better understanding shutter behaviour in various circumstances.

FDR, I hope your investigation sheds some light on the nature of the EQA's actuator. By the way, I found it easier to remove the undertray with the front wheels removed, but you might find that's unnecessary. Note carefully the placement of the flexible shield which you'll expose when you remove the main front undertray section.

The flexible shield sits very close to the lowest shutter blade and when I removed my flexible shield I noted that where it ran alongside the actuator wiring loom it was partly folded up into the shutter space. I query whether that flexible shield actually impeded the full opening stroke of the lower shutter blade and damaged the actuator. I think it's a long shot, but it remains a possibility. I think it depends on which is the weakest link in the actuation chain.

 

[FDR]

I removed the undertray and had a look at the slats mechanism, without wanting to remove too much, I think the actuator box probably contains reduction gears and maybe a limit switch. It’s just possible to see a splined cross shaft going through the top of the box from right to left which will drive the linked slats.
My slats were still open after having driven forty minutes or so and I was afraid they’d be stuck, but actually they do operate, I discovered I was able to gently lever them closed and the motor immediately opened them again. That was with the car unlocked with the doors closed but nothing switched on inside. They were determined to stay open as I couldn’t lever them shut again.
I’m not sure why your actuator is trying to move the slats when the car is parked, if they are open and meant to be open at that time there’s no need for any movement. It would appear the rattling is caused by it trying to open the already open slats for some reason.
It would seem dBC is correct in saying the purpose of the slats is to aid streamlining, (EQC owners have their uses sometimes!!) they will close when the car is moving, opening again when the car stops to increase cooling airflow particularly when charging.
It may be your flexible shield has jammed the slats as you said, it’s hard to imagine what could push it up that far, but I feel the fault is more to do with the actuator driving when it doesn’t need to.

 

[EQA-S.oz]

I feel the fault is more to do with the actuator driving when it doesn’t need to.

I tend to agree with you, FDR. Perhaps when the dealer investigates the fault further there'll be some fault codes which will shed some light on it - although I'm continually amazed at the reports of various makes of car which clearly have problems in respect of which you'd expect a fault to be registered, but it isn't.

 

[EQA-S.oz]

I have now collected my EQA from the dealer and apparently - as expected - the problem was an electronic fault within the front shutter actuator. The dealership is only about 3km from our home and it is a mild day here (high 'teens to say 20 degrees Celsius). The car has been sitting for about 3 hours in our garage. When I arrived home the shutters were open and they're still open.

This all seems consistent with FDR's report - but, interestingly, the opposite to dBC's report of the EQC.

I expect my reversing camera kit and 12v wireless remote (to momentarily connect positive feed to the camera in lieu of activation by selecting reverse gear) to arrive next week, so that I can hopefully monitor the shutters under various circumstances. I'll update this thread when I have more to report.

 

[FDR]

I have now collected my EQA from the dealer and apparently - as expected - the problem was an electronic fault within the front shutter actuator. The dealership is only about 3km from our home and it is a mild day here (high 'teens to say 20 degrees Celsius). The car has been sitting for about 3 hours in our garage. When I arrived home the shutters were open and they're still open.

This all seems consistent with FDR's report - but, interestingly, the opposite to dBC's report of the EQC.

I expect my reversing camera kit and 12v wireless remote (to momentarily connect positive feed to the camera in lieu of activation by selecting reverse gear) to arrive next week, so that I can hopefully monitor the shutters under various circumstances. I'll update this thread when I have more to report.

Glad to hear you got the problem sorted, did they replace the actuator or were they able to fix it?
It’ll be interesting to hear the results from your camera monitoring idea.
I can’t understand why dBC’s EQC shutters are working opposite to ours unless Mercedes thought they were getting a problem (maybe related to the cooling issues others have reported) on the EQC which could be helped by keeping the shutters open as a default when they made the newer EQA model.

 

[EQA-S.oz]

I believe they replaced the actuator, as they kept the car for one extra day due to a "delay in the arrival of the parts" - or maybe it was "part" - which I assume was the actuator, as they said that was the sole problem. Apparently a fault code was registered which was consistent with that.

Since returning from the workshop, while standing idle, I've noticed that my EQA goes through the same somewhat intermittent routine that I mentioned in my initial post in this thread - click of a switch, followed by a whirring noise - but now, thankfully, it's not followed by the rattling noise and the shutters seem to remain fully open.

The repair was an interesting experience from my end, as Mercedes me kept informing me about windows, doors, sunroof (I've never used it) and bonnet being open at various times. When I mentioned this to the service reception person he said that they check the operation of all windows and the sunroof as a matter of course during any workshop procedure. I was pleased to note that they also topped up the coolant reservoir (it had been slightly below the full mark). There was no charge for any of the work.

The dealership loaned me a 1,500 km demonstrator GLA200 while my car was in their workshop. I quite liked its alcantara seat inserts and I thought the Continental tyres (the same size as the EQA) were a bit less harsh over road imperfections than my Bridgestones, but otherwise I was pleased to be back in my EQA.

More on the observation of my car's shutters in due course.

 

[DJL]

Is this the noise? EQA350 noise

 

[EQA-S.oz]

Unless it's from another source, that sounds exactly like what proved to be the malfunctioning (i.e. non-operational) radiator shutter actuator on my EQA250. I'm interested to know how you triggered the successive activations recorded in the video.

 

[DJL]

Unless it's from another source, that sounds exactly like what proved to be the malfunctioning (i.e. non-operational) radiator shutter actuator on my EQA250. I'm interested to know how you triggered the successive activations recorded in the video.

I didn’t trigger them. The noise was just one long noise for the first 20th times and now it has become 1short followed by 1longer noise since then. They seem to happen about 15-20 minutes apart and definitely happen about 5 seconds after you power it on. The noise seems to be linked to temperature. I drove about 140km on a hot(34degree) and humid day with the aircon on a the sound started about 10 minutes after I parked. It continued for a few hours every 15 minutes or so. The slats were open and are still open. The noise stopped around 8 at night when everything had cooled down to about 22degrees. The noise started again around 9.30 in the morning when the world had warmed up to about 28degrees. After about 5 cycles of the noise I powered up the vehicle to take it to the dealer and that triggered the noise again. When at the dealer I powered off, told them of the problem and then powered on again which triggered the noise for them. I then signed some paperwork to leave it with them and while doing that it spontaneously made the noise again. It is a 14day old EQA350 with 800kms on the clock.

 

[EQA-S.oz]

I didn’t trigger them. The noise was just one long noise for the first 20th times and now it has become 1short followed by 1longer noise since then. They seem to happen about 15-20 minutes apart and definitely happen about 5 seconds after you power it on. The noise seems to be linked to temperature. I drove about 140km on a hot(34degree) and humid day with the aircon on a the sound started about 10 minutes after I parked. It continued for a few hours every 15 minutes or so. The slats were open and are still open. The noise stopped around 8 at night when everything had cooled down to about 22degrees. The noise started again around 9.30 in the morning when the world had warmed up to about 28degrees. After about 5 cycles of the noise I powered up the vehicle to take it to the dealer and that triggered the noise again. When at the dealer I powered off, told them of the problem and then powered on again which triggered the noise for them. I then signed some paperwork to leave it with them and while doing that it spontaneously made the noise again. It is a 14day old EQA350 with 800kms on the clock.

The behaviour you report, DJL, is entirely consistent with my findings in the research I'm currently performing on my EQA250, intimated in (my) post #14 above. I can't believe it was that long ago! I am also alarmed - as, I suspect, are you - that this fault has occurred in such a new car!

Using a wireless reversing camera mounted behind the shutters (or slats), an Arduino device I've created which monitors the timing of shutter opening and closing and a 4-sensor wireless BBQ thermometer, I am gathering data on shutter opening and closing and coolant temperature. The coolant temperatures are measured by sensors attached to the outside of 3 coolant hoses, so they are only approximate, but they're nevertheless creating a picture, which I'll provide once I've got more reliable data.

Suffice to say that the shutters open and close quite often and their resting state on my car seems to be "open". As you've mentioned, they'll even actuate when nothing otherwise seems to be happening - although, if you listen carefully, you may also hear one or more of the 5 coolant pumps cycle briefly. Typically, when I begin a journey (from cold), they close then either immediately re-open, or stay closed for some time. I agree, opening and closing seems to be temperature-related, but vehicle speed also seems to be a factor - and no doubt there are others.

Whilst various opinions were offered in the posts above, it would be interesting to know what actually creates the noise that you recorded, because in normal operation, shutter actuation is very quiet.