W212 aux "after-run" pump
Thread Starter
Junior Member
Joined: Jun 2022
Posts: 33
Likes: 7
From: Columbia, SC
2015 E63 S
W212 aux "after-run" pump
Anyone else have experience with your cars after-run pump running for 60-90 minutes after shutting down when it's really hot outside? Mine intermittently runs for around 90 min in the evening and since I'm new to the brand (I come from Audi/Porsche) I thought I would ask here as I can't find any info on this. My oil and coolant temps have been fine. No overheating, no leaks, car runs just fine. Thanks in advance!
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Joined: Jan 2012
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From: NYC
E63S
Are you referring to this "noise" that sounds like a fan that seems to come from the front most passenger side? If so, no, I only hear that for about a minute or less. Full disclosure. I always open the hood when I park my car in my garage. Read some stuff about how some owners do this in order to decrease the effects of under the hood high temps cooking rubber hoses and miscellaneous parts brittle.
Thread Starter
Junior Member
Joined: Jun 2022
Posts: 33
Likes: 7
From: Columbia, SC
2015 E63 S
Nope. It's an electric "whirring" noise that comes from the drivers front in and around the exhaust manifold / front of the engine. Hard to pinpoint but definitely in and around the area where the accessories are. Can't find a schematic or diagram showing where this Aux pump resides and what it's function is.
MBWorld Fanatic!
Joined: Jan 2012
Posts: 1,043
Likes: 310
From: NYC
E63S
I suppose that I could describe that "fan sound" I am referring to as a "whirring". In my case, it definitely originates form the passenger side. But, regardless of which side, I can definitively tell you that my car does NOT make any sort of sounds (aside from the quick dump from the air suspension) past a minute following power down. Please post up if you find the answer to your question.
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14 E63, 05 E55, 03 Evo 8, 08 F250, 06 R6R, 92 Talon TSI, and instability
Anyone else have experience with your cars after-run pump running for 60-90 minutes after shutting down when it's really hot outside? Mine intermittently runs for around 90 min in the evening and since I'm new to the brand (I come from Audi/Porsche) I thought I would ask here as I can't find any info on this. My oil and coolant temps have been fine. No overheating, no leaks, car runs just fine. Thanks in advance!
Thread Starter
Junior Member
Joined: Jun 2022
Posts: 33
Likes: 7
From: Columbia, SC
2015 E63 S
I have had this happen a few times since owning the car. Its like that pump/fan "hiccups" and gets stuck in a looped "on" cycle. The trick to getting it to stop when it goes into the seemingly endless cycle is to unlock, open, close, and relock the driver's side door at a deliberate pace. Think I did it once with the passenger door too. Essentially, you have to "remind" the car on occasion that it's off.
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Joined: Oct 2019
Posts: 155
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E63S
it won't.
You have a main battery and an aux battery that handles things like this. The car is, fortunately, smart enough not to drain your battery with auxiliary tasks, so you'll still have the ability to start the car.
It also runs because you're trying to cool a 577hp engine. Horsepower makes heat, no way around it. Add in summer conditions (especially in humid areas), parking it in a garage after being ran where there's very little air flow, a clsoed hood heat-soaking the whole engine bay, and the car will try to run the cooling pumps for a bit in hopes to maintain some semblance of longevity.
You have a main battery and an aux battery that handles things like this. The car is, fortunately, smart enough not to drain your battery with auxiliary tasks, so you'll still have the ability to start the car.
It also runs because you're trying to cool a 577hp engine. Horsepower makes heat, no way around it. Add in summer conditions (especially in humid areas), parking it in a garage after being ran where there's very little air flow, a clsoed hood heat-soaking the whole engine bay, and the car will try to run the cooling pumps for a bit in hopes to maintain some semblance of longevity.
