Chevy and GMC Duramax Diesel Forum banner

1 - 20 of 52 Posts

·
Registered
Joined
·
45 Posts
Discussion Starter #1
Has anyone else had a sound similar to a bearing going out, while at idle? It only does it when it's warm and stops as soon as the rpm are brought up off idle. The best I can describe it other than a worn bearing is a "whirring" sound.

Took the truck to the dealer (while it was warm and making the noise). The mechanic started looking at charge tubes for loose connections and didn't find anything. Today they called and said they had contacted Chevrolet and they thought it was the EGR. They have order new parts and gaskets and will call me when they arrive.

Curious if anyone else has experienced this and, if it was in fact the EGR system.
 

·
Registered
Joined
·
87 Posts
I was wondering if my front driver bearing was going out for a while as well. I would hear it when I was driving around 45 MPH, but not all the time. I found when the truck was warm enough it would shift into 5th and with the converter locked it would drop my RPM's around 1200. Then it made the noise. If I manually change the gear back to 4th the noise stopped. So I finally realized it was just the noise of the engine being lugged and the exhaust system vibrating from it.

Sent from my PH-1 using Tapatalk
 

·
Registered
Joined
·
841 Posts
Would have to hear the noise (in person is usually best) to help track it down. I would start with the obvious: alternator, power steering pump, a/c compressor, fan bearing, then Idlers. I know my power steering pump on the 04 makes noise at weird RPM even though its full. Need to change the fluid in that one.
 

·
Registered
Joined
·
45 Posts
Discussion Starter #4
I was wondering if my front driver bearing was going out for a while as well. I would hear it when I was driving around 45 MPH, but not all the time.
Mine only makes the noise when the engine is at idle. As soon as I give it any fuel the sound goes away. Not sure how the Exhaust Gas Recirculation could make that type of sound but, I guess I will let them replace the system and see if that does it.

Thanks for the replies.
 

·
Registered
Joined
·
841 Posts
Mine only makes the noise when the engine is at idle. As soon as I give it any fuel the sound goes away. Not sure how the Exhaust Gas Recirculation could make that type of sound but, I guess I will let them replace the system and see if that does it.

Thanks for the replies.
Try removing the belt when its warm and making the noise. Could be any of the accessories on the front. Fan support, idlers, alternator, air conditioner compressor, and power steering pump all runs of the belt. Bearings in those are man made so anything is possible. If just coming off an oil change, water pump is gear driven and they have been known to make noise when aftermarket were used, could be a fluke one. Cam shaft is also gear driven. Can you isolate the noise to the engine bay or to the transmission tunnel? Could be torque converter, check the trans level when hot, aim for bottom of has not top as they can be over filled which leads to cavitation.
 

·
Registered
Joined
·
45 Posts
Discussion Starter #6
Dealership called today and said they had the EGR system parts and gaskets in to replace. Will take it in and have that done and see if it stops the noise. It's still under warranty (not quite a year old yet and less than 13k miles) so I'm going to let them figure it out. I will let you know how we progress.
 

·
Registered
Joined
·
45 Posts
Discussion Starter #7
Got my truck back this afternoon. Didn't have time to drive it 30+ miles (which is what it has taken before to make the noise). Did drive it to fill the tank and then home, no sound so far. They replaced the EGR valve and new gaskets - so...... we'll see if that cured it.
 

·
Registered
Joined
·
45 Posts
Discussion Starter #8
And.........It's back:| Drove the truck long enough the other night to get it well warmed up and the noise is there again. Took it up to the dealership today and they can't get it in until Wed. after Christmas! Told them I needed transportation and they said to drive it until I take it in. I asked what happens if this is doing damage, if that will all be covered by warranty? They were less than confidence inspiring! We'll see what happens next........
 

·
Registered
Joined
·
45 Posts
Discussion Starter #9
Well, the saga continues. They had my truck for two more days - still can not figure out what it is. I called Chevy Customer Care and they have started a case and "referred it to a senior case agent" (whatever that means!). Today the dealership called and said to come pick it up, they have no ideas and didn't want me to be without transportation (since Chevy won't provide a loaner). They are going to contact Chevy Tech again and try to figure something out. THIS IS GETTING REALLY OLD, really fast! Anyone know what it takes for Chevy to give in and give you another new '18 or a new '19?
 

·
Registered
Joined
·
45 Posts
Discussion Starter #10
Try removing the belt when its warm and making the noise. Could be any of the accessories on the front. Fan support, idlers, alternator, air conditioner compressor, and power steering pump all runs of the belt. Bearings in those are man made so anything is possible. If just coming off an oil change, water pump is gear driven and they have been known to make noise when aftermarket were used, could be a fluke one. Cam shaft is also gear driven. Can you isolate the noise to the engine bay or to the transmission tunnel? Could be torque converter, check the trans level when hot, aim for bottom of has not top as they can be over filled which leads to cavitation.
They checked the drive pulleys and said that wasn't it. Don't know if they checked the trans fluid level - will try to get out and get it warmed up tomorrow and check that myself. I can't determine where it is coming from, it's louder standing in front of the truck as opposed to the side by either front wheel. Not recent on the oil change, in fact, I'm due for another change in about 1k miles.
 

·
Registered
Joined
·
87 Posts
If they cannot fix then you might be able to make them buy it back with the lemon law. I had a Trailblazer that had a strange noise on the interstate, dealer found it was a coil spring in the rear making the noise.

Sent from my PH-1 using Tapatalk
 

·
Registered
Joined
·
87 Posts
You said it is more upfront than sides of the engine bay... Check things like the headlights, intake tubes, resonator, radiator, transmission cooler, etc. that could be vibrating? Does it matter if the hood is closed or open?

Sent from my PH-1 using Tapatalk
 

·
Registered
Joined
·
45 Posts
Discussion Starter #13
Noise is about the same, hood opened or closed. It's not a vibration or rattling, it's definitely a metal rubbing against metal sound. The tech at the dealership first thought it was something in the charge tubes and checked all the fittings. He found nothing. The dealership is supposed to call me Mon. or Tues. and let me know where we are on the whole issue, so.........
 

·
Registered
Joined
·
841 Posts
I think you need to get it warm and pull the belt. You said dealer checked it, but most of the times I have had something in there to be checked and they said it was checked, but it was not.

You might also want to check the rotation of the engine in the mounts when its sitting. With hood open, start truck, hold brakes, put in drive and rev slightly to check the motor mounts are not allowing excessive motion. This typically checks only the one. IIRC the Dmax motor mounts are fail safe so there is metal to metal contact when the rubber in it falls apart.
 

·
Registered
Joined
·
45 Posts
Discussion Starter #16
I think you need to get it warm and pull the belt. You said dealer checked it, but most of the times I have had something in there to be checked and they said it was checked, but it was not.

You might also want to check the rotation of the engine in the mounts when its sitting. With hood open, start truck, hold brakes, put in drive and rev slightly to check the motor mounts are not allowing excessive motion. This typically checks only the one. IIRC the Dmax motor mounts are fail safe so there is metal to metal contact when the rubber in it falls apart.
Yeah, I've had that experience too with work being "done" when they didn't! I'm not sure how it would be motor mounts - the sound is a constant, even "whirring" sound. I would think motor mounts would be an uneven chirping sound.

As far as the torque converter - I'll have to look at that closer, although the sound is louder from the front of the truck as opposed to by either front tire. Seems like the TC would be louder from the side(?). I'll take a look.

Thanks!
 

·
Registered
Joined
·
45 Posts
Discussion Starter #17
Going to vent a little..... Received a call back from Chevrolet Customer Service. They said they were working on diagnosing the issue but that they did not have a known reason for, or cure for the noise. I asked how they were doing that as the truck is in my driveway and they said they have others doing the same. I told them (again) I did not want to drive my truck while it was making the noise as it has to be doing some damage somewhere (it sounds to me like metal on metal). They advised that they would not authorize a loaner until the problem had been diagnosed and that it was not a "safety concern". I asked how she knew it wasn't a safety concern if she didn't know what it was? They said they had done all they could for me until it was diagnosed. (This is where I got a little hot under the collar). I asked her if she had purchased a $66k truck just over a year ago, and had only driven it 13k miles and it was doing this - how would she feel? Didn't make a difference! Still no loaner! Told her I wanted to speak to her supervisor, was put on hold for about 12 minutes and then was told the same crap by the supervisor.

Went back to my local dealership and contacted the manager. Told him about the phone conversation and told him I was NOT impressed with their company. Took him out to the lot to listen to the truck and he agreed it was not right. He took a video of it and the noise and said he would e-mail that to their tech people working on the issue. He spoke with the service writer I have been talking to and asked me to bring the truck in this Wednesday and said they would have a loaner for me and would "dig into it" to figure out the problem.

Sooooooo.........hopefully we are finally starting to make some progress. The sound, with the hood open, is definitely louder in the center of the front of the engine, with it equal walking to either side from the center. The saga continues.

Sorry for the long post - really tired of the run around I am getting from Chevy Corporate.
 

·
Registered
Joined
·
45 Posts
Discussion Starter #18
Update - Now they say they think it is the wastegate on the turbocharger. They are ordering a new turbo and will install it when it arrives in "about a week". I'm no mechanic, but I don't see how a turbo wastegate would make a noise when the turbo is not producing boost. Will update in a week or so, when the new turbo is on the truck and we see if the noise has gone away or not......
 

·
Registered
Joined
·
1,084 Posts
Does the L5p have a waste gate, I thought it was a vgt. Any way a real waste gate could get stuck in a position where you couldn’t build boost and the escaping boost could produce a high pitched noise similar to a whistle.
 

·
Registered
Joined
·
6,063 Posts
It's vgt.

https://gmpowertrain.com/engines/docs/GMQD16CLM70_L5P_Product PDF.pdf


Electronically Controlled, Variable-Geometry Turbocharging System
• Advances the Duramax legacy of variable-geometry boosting, creating more power
in the engine
• Revised design enhances the capability of the exhaust-brake system
• New variable-vane turbocharger enables the engine to deliver more power with
lower exhaust emissions
 
  • Like
Reactions: sargenthp
1 - 20 of 52 Posts
Top