jr_north

The fuel pump on my 2014 GLK Blutec was just changed under warranty... Question I forgot to ask the dealership: when I turn off my GLK there is always the sound of a pump running for about 30 secs, is that normal? It is in the rear end of the vehicle so I assumed it had to do with the fuel pump or DEF fluid. The vehicle has always done this so I thought it was normal.

Plutoe

I would go back to the dealership as I could not find any instructions in the engine ECU documentation to run the fuel pump after key off.

My WAG is you have a faulty fuel pump relay!!

jr_north

I have sent the attached audio file to the dealership...
What do you think...

Plutoe

Thanks, but the only folks that need to see and hear the car, not a wav file is the dealer!!

Shadow5501

Stupid question, but are you sure it's coming from the back? Every recent supercharged and turbocharged MB I've had runs the intercooler pump for 30 seconds after the engine is shut down. It makes a high pitched whine sound. But this pump would definately be under the hood.

jr_north

Definitely in the back end... I posted a recording above: I was under the back emd when I recorded the sound...

jr_north

Pump noise after shutdown is normal...

Here is the note from the dealership...

"As discussed on the phone, the noise that you are hearing after shutting the car off is normal. Your car has a saddle tank so when the car starts it only draws from one side of the tank. The pump noise you are hearing is and internal pump that sends the fuel from one side of the tank to the other."

I must say I am surprised he didn't already know this...