Buzzing sound after shutdown

[SCOverlander]

Hello JL 3.0 owners,
I finally picked up the diesel and did the 600 mile drive home. The motor is amazing. Fast, powerful, and averaged 27 mpg driving 70-80.
As soon as pulled into the driveway I noticed a buzz/hum from the engine bay after shutdown. The noise last for 3 minutes and then goes away. I do have a call into into dealer but haven’t heard back. I don’t think this is normal but don’t know.

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[hazards280]

The sound you're hearing is a pump circulating coolant through the turbo and intercooler. This is done to help cool these components and prevent heat soak from causing damage.

Note, I own a Alfa Romeo Giulia (turbo as well) and it makes the exact same noise when its turned off. Other owners have asked the question and Alfa responded back with the details.

 

[SCOverlander]

Thank you for the quick response. Makes total sense. Just a bit of concern when it’s new to me.

 

[Oilburner]

The sound you're hearing is a pump circulating coolant through the turbo and intercooler. This is done to help cool these components and prevent heat soak from causing damage.

1. Thanks, I wondered what that noise was.
2. Yet another reason not to keep a vehicle more than a few years - so complicated. (Or maybe I’m just getting older? OR BOTH!)

 

[limeade]

1. Thanks, I wondered what that noise was.
2. Yet another reason not to keep a vehicle more than a few years - so complicated. (Or maybe I’m just getting older? OR BOTH!)

This is a common cool-down procedure for modern turbo diesel engines. You WANT it to do this. Before manufacturers installed this auto cooling, you were supposed to let the engine idle for up to several minutes prior to every shut down in order to get the turbo and EGR temps back into a acceptable range. This is/was especially important after hauling heavy loads, going up steep grades, etc. Shutting down a diesel engine when the EGR temps are high will lead to a short engine life.

 

[crazyjas]

The diesel supplemt states the amount of time the engine should idle/cool down based on the type of driving before shutting off engine

 

[No Spark V6]

I was wondering the same thing. Good to know!

 

[Killdozer]

I was wondering the same thing too. I have been letting it idle for a minute or so but its nice to know that won't be needed anymore.

 

[JimLee]

They should have just integrated a turbo timer that keeps the engine running for a predetermined amount of time (or to a specific temp) after you shut the vehicle off, and then shuts it down automatically.

 

[xylodan]

Hooray! Question answered using the search function.
I figured the noise was normal and nothing to be concerned with, but it is definitely unique to any vehicle I've had before that had more mellow sounding shut down noises.

 

[WXman]

Are we certain that's what the buzzing is? Because the sound comes from the CP4 injection pump.

Turbo cooling would make more sense, though.

 

[Oilburner]

Digging up this thread, my diesel Wrangler has buzzed after shutoff since new (more like a hum), but today after a run to town, the buzzing is easily 5X Louder than ever before ?

 

[SCOverlander]

Digging up this thread, my diesel Wrangler has buzzed after shutoff since new (more like a hum), but today after a run to town, the buzzing is easily 5X Louder than ever before ?

I would think if the noise is now louder then that may not be normal. Are you going to take it in?

 

[Oilburner]

I would think if the noise is now louder then that may not be normal. Are you going to take it in?

adding some fuel treatment & topping off, will monitor- dealer won’t do anything until something breaks anyway. Note: I did get fuel from an unfamiliar station last time-

 

[TJ_HOOKER]

I thought it was a cool down cycle as well but It’s the fuel system. Green Diesel Engineering explained it to me that only the Jeep does this after shutting off and the Ram does not so it’s disabled as part of their tune.

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