2012 ML350 BlueTec issues

Apr 29, 2025 | 11:37 PM

206113@

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W166

2012 ML350 BlueTec issues

Hi guys, I just got a 2012 ML350 BlueTec — two quick questions:

Should it beep when the indicator is on?
Will the "engine" light come on the dash if the thermostat is broken?

Anyone know? Thanks!

Apr 30, 2025 | 08:07 AM

bobofthenorth

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Joined: Oct 2023

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From: Buchanan, SK CANADA

2013 ML350 Bluetec

Quote:

Originally Posted by 206113@

Hi guys, I just got a 2012 ML350 BlueTec — two quick questions:

Should it beep when the indicator is on?

Should what beep when what indicator is on?

Last edited by bobofthenorth; Apr 30, 2025 at 10:19 AM.

Apr 30, 2025 | 09:56 AM

rapidoxidation

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Joined: Jan 2016

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From: In the Shadow of the Tetons

2013 ML350 Bluetec

The turn signal indicator barely goes "click" and that's because it has a noisemaker. It's electronic.
Yes. If the thermostat doesn't get the engine to the temperature the ECU expects in the time the ECU expects it to get there, it'll throw a code.

Last edited by rapidoxidation; Apr 30, 2025 at 10:00 AM.

Apr 30, 2025 | 09:59 PM

206113@

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W166

thanks, mate.
I bought this vehicle two years ago, and I'm sure the thermostat was broken because the coolant temperature couldn't reach the normal level. However, I didn’t see any warning or error message on the dashboard.

Another thing — does this ML need AdBlue refills? I see there’s an AdBlue tank, but I haven’t received any refill warnings, even after driving over 20,000 km.

Apr 30, 2025 | 11:11 PM

bobofthenorth

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Joined: Oct 2023

Posts: 117

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From: Buchanan, SK CANADA

2013 ML350 Bluetec

Quote:

Originally Posted by 206113@

thanks, mate.
Another thing — does this ML need AdBlue refills? I see there’s an AdBlue tank, but I haven’t received any refill warnings, even after driving over 20,000 km.

In factory trim it needs AdBlue. At 20,000 km I suspect your car has been deleted. Look for loose connectors which were previously attached to parts of the BlueTec system. There should be a couple under the chassis where they would have attached to the DPF. There will also be a great big one in the right rear quarter panel next to your auxiliary battery but its a little tricky to see. You may be able to see it through the inspection hatch over the battery using a mirror. Its big - like 1.5 inches by 4 inches.

Apr 30, 2025 | 11:55 PM

206113@

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W166

thanks, mate, is there any negative impacts if it's removed for this vehicle?

May 1, 2025 | 06:43 AM

bobofthenorth

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Joined: Oct 2023

Posts: 117

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From: Buchanan, SK CANADA

2013 ML350 Bluetec

Quote:

Originally Posted by 206113@

thanks, mate, is there any negative impacts if it's removed for this vehicle?

Depending on your jurisdiction there may be legal implications. Personally I think there is nothing but good mechanically. When I bought mine it was pretty much the first thing I did but I live in a jurisdiction without annual re-inspections. I think I could pass one but I don't have to so it doesn't matter.