Anyone know what the buzz is all about?

[ChubbyUnicorn]

First eco diesel but have had lots of diesel trucks in the past. What is this annoyingly loud buzz after driving around for a while. It goes for a few minutes after I stop.

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[BDinTX]

Not certain but I think it’s running coolant through the turbo. Mine does it too.

 

[grimmjeeper]

Yep. It is circulating either oil or coolant to bring down the turbo temp.

 

[ChubbyUnicorn]

Ok. Ecodiesel version of a turbo timer to cool things down a bit. Thanks for the info.

 

[Rhinebeck01]

Compare sound to ETC sound mentioned here. I know your JL is a diesel.

https://www.jlwranglerforums.com/forum/threads/high-pitch-noise-from-engine-bay…what-is-it.122253/

 

[ChubbyUnicorn]

Compare sound to ETC sound mentioned here. I know yourr JL is a diesel.

https://www.jlwranglerforums.com/forum/threads/high-pitch-noise-from-engine-bay…what-is-it.122253/

It is similar. I had to get my wife to listen as her ears are better. She says mine is more of a buzz and deeper tone. It’s happened after every extended drive I’ve done the past few days since I got it. Now when I hear it, it does sound like the coolant pump on my CNC mill.

 

[Old Jeeper]

Not certain but I think it’s running coolant through the turbo. Mine does it too.

X2

 

[Grayhound]

I thought I read somewhere that this is the def pump emptying the def lines back into the holding tank.

 

[ChubbyUnicorn]

I just talked to a buddy who's a diesel mechanic and he said that is a coolant pump to cool and lubricate the turbo if you shut off the engine to quickly. He reminded me to let it idle for a minute or so after highway driving or about 30 seconds after just going around the city and we shouldn't hear it. Living in Arizona in the hot season it may need to idle longer.

 

[Jeep Wick]

I just talked to a buddy who's a diesel mechanic and he said that is a coolant pump to cool and lubricate the turbo if you shut off the engine to quickly. He reminded me to let it idle for a minute or so after highway driving or about 30 seconds after just going around the city and we shouldn't hear it. Living in Arizona in the hot season it may need to idle longer.

You don't need to let it idle, the whole idea of the aux pump is you can turn it off without worrying about damage. The ecu does the math, save your fuel.

 

[Wrangler man]

You don't need to let it idle, the whole idea of the aux pump is you can turn it off without worrying about damage. The ecu does the math, save your fuel.

The Eco diesel supplemental manual states differently. It gives very specific extended run cool down times before shutting down. Based on type of driving including towing.

 

[StartedWith97TJ]

I thought I read somewhere that this is the def pump emptying the def lines back into the holding tank.

+1

The buzzing sound that runs for about a minute after shutting down the eco-diesel is the def pump emptying the lines. If you just turn the ignition on and off, or start the engine for a second and turn it off, you will hear the buzzing sound. It is not related to turbo temperatures.

keep Jeep’n

 

[Tread4Lo]

That buzz is always there. Seems like it was circulated for a while that it is the HPFP doing something as well. So the three speculations are: 1) DEF return 2) Turbo cooldown or 3) HPFP return.

I remember reading (my not be correct) people that have gotten their Jeep tuned have stated the tune stopped the buzzing.

 

[Zombie crawler]

Mine will sound off even if I don’t start it and it’s cold so it’s nothing to do with coolant for the motor.

 

[AC77]

if its a bussing noise after shut down, its the aux pump cooling the turbo, goes on about 1-2 minutes

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