Ticking sound at idle

Bones454 · July 4, 2020

Well up to 500 miles on mine, but got home today and backed into the basement and heard a ticking sound. Fist time I noticed it probably because I had the window down, don’t do that most of the time.

MTU Alum · July 5, 2020

If it is on the passengers side of the truck, it's likely the DEF injection. This ticking sound is normal on L5P equipped trucks.

#iworkforGM

Tomato · July 5, 2020

4 hours ago, MTU Alum said:

If it is on the passengers side of the truck, it's likely the DEF injection. This ticking sound is normal on L5P equipped trucks.

#iworkforGM

Is what you are describing the "thump" or knock we have? Has GM now confirmed it is the DEF injection? Thanks.

MTU Alum · July 5, 2020

The tick and thump are two different noises that both have bulletins on. The tick is DEF injector. The thump I don't have a lot of info on. From the bulletin, when you remove fan belt the noise goes away. This leads me to believe that belt is setting off a mode in another component. The thump goes away rpm change which proves it's frequency based. Neither issue causes any type damage to the powertrain or any other component.

#iworkforGM

Bones454 · July 27, 2020

Yes, was def injection and don’t pay attention to the thump it’s a diesel and really don’t hear it.

buelldude · September 12, 2020

the thump that I get like many other isn't there when started and comes on more as temp goes up, but no one knows what it is????? Some do it, others don't. Some say it goes away after the belt is off, some say it doesn't change.

I got it at 400+ miles and would rather know what the problem is, not just a guess. My other 6.6 didn't do this so is it the motor/trans of fan?

redwngr · September 17, 2020

2020 has a much different accessory belt system than the previous generations.

Charles Ha11 · October 28, 2020

There is often times what I would call an erratic ticking noise that is often heard at idle. I have seen this refereed to a "excited oil that can be from the oil coming through the lifters Look for Duramax excited oil with google and you will see many articles on it. this is my 4th duramax and the last three have produced this sound it is nothing to be alarmed about