NSnyder996

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!

NSnyder996

Anyone??

Rehabguy

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.

NSnyder996

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.

Rehabguy

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.

Mojo20032004

Mine does it after some hard runs. It's the intercooler coolant pump cycling coolant through the system.. Kinda like a turbo timer..

chassis

“Circulation pump” behind the front headlamp or near it. Common across many MB models in the W212/213/222/205/166 time frame.

PeterUbers

Normal.

Rehabguy

1-1.5 hrs after shut down?

WANTED!!

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.

AngryScotsman

This.

Yes.

NSnyder996

Thanks for the reply and to everyone else too. You'd be surprised just how many people aren't aware of this feature. I've been opening the hood when I get home and that has cut down on the run time. I've purposely been going out to my garage after I get home every 30 minutes to see if it's still running. I think tonight I'll lock the doors and come out after 30 minutes and see if it's still running or not. I noticed that if I go out to the car after a few hours and the pump is NOT on, once I open the drivers door it starts all over again.... even if I never start the engine. Again, I knew what this was but was curious if anyone else had this issue or not. Running that long has to drain the battery.

AngryScotsman

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.

ygmn

why is none of this in manual?