2015 2500HD 6.0L squeal on startup

corn18 · August 14

Howdy. About a year ago my 2015 2500HD 6.0L flex fuel developed a loud squeal on the first startup of the day. Only happens on the first startup even if the truck sits for a long while after the first startup. I have changed the serpentine belt, tensioner pulley and the idler pulley. Still there. I tried listening with one of those stethoscope thingies but the radiator fan is too loud. Before I take it to a stealer, what else can I troubleshoot? Thanks!

Here's a link to a video on facebook. Not sure how to post it directly here.

https://www.facebook.com/100004961733954/videos/493003216698713/

Edited August 14 by corn18

newdude · August 14

1 minute ago, corn18 said:

Howdy. About a year ago my 2015 2500HD 6.0L flex fuel developed a loud squeal on the first startup of the day. Only happens on the first startup even if the truck sits for a long while after the first startup. I have changed the serpentine belt, tensioner pulley and the idler pulley. Still there. I tried listening with one of those stethoscope thingies but the radiator fan is too loud. Before I take it to a stealer, what else can I troubleshoot? Thanks!

IMG_5967 3.MOV

Have you taken the belt off and started it briefly? Don't leave it running long as the water pump won't be spinning, so maybe 10-20 seconds quick to see if the noise goes away. If its gone, could be a bad water pump.

If the noise is still there without the serpentine belt on, I'd remove the AC compressor belt and retest, see if the noise goes away. If it goes away after that, its the AC compressor.

If the noise is present with either belt off, you've got an internal issue like a lifter spun in the bore.

corn18 · August 14

2 minutes ago, newdude said:

Have you taken the belt off and started it briefly? Don't leave it running long as the water pump won't be spinning, so maybe 10-20 seconds quick to see if the noise goes away. If its gone, could be a bad water pump.

If the noise is still there without the serpentine belt on, I'd remove the AC compressor belt and retest, see if the noise goes away. If it goes away after that, its the AC compressor.

If the noise is present with either belt off, you've got an internal issue like a lifter spun in the bore.

Coolio. Will try that in the morning. Can only troubleshoot one thing a day.

corn18 · August 18

On 8/14/2024 at 12:31 PM, newdude said:

Have you taken the belt off and started it briefly? Don't leave it running long as the water pump won't be spinning, so maybe 10-20 seconds quick to see if the noise goes away. If its gone, could be a bad water pump.

If the noise is still there without the serpentine belt on, I'd remove the AC compressor belt and retest, see if the noise goes away. If it goes away after that, its the AC compressor.

If the noise is present with either belt off, you've got an internal issue like a lifter spun in the bore.

Ok, finally got around to this. I removed the serpentine belt and started the truck. No squeal or odd noises, so the air conditioner compressor is not the source. Replaced the serpentine belt and the squeal was there. I also removed the clutch fan and the squeal was still there. So I guess it is either the water pump or the power steering pump. I did turn the steering wheel and the squeal did not change so would my best bet be to change the water pump?

Edited August 18 by corn18

newdude · August 18

1 hour ago, corn18 said:

Ok, finally got around to this. I removed the serpentine belt and started the truck. No squeal or odd noises, so the air conditioner compressor is not the source. Replaced the serpentine belt and the squeal was there. I also removed the clutch fan and the squeal was still there. So I guess it is either the water pump or the power steering pump. I did turn the steering wheel and the squeal did not change so would my best bet be to change the water pump?

Yea sounds like its the water pump. I assume you left the AC belt on as its a separate belt on these engines so if it was quiet without the main belt you can rule the AC out yes.

corn18 · August 18

16 minutes ago, newdude said:

Yea sounds like its the water pump. I assume you left the AC belt on as its a separate belt on these engines so if it was quiet without the main belt you can rule the AC out yes.

Yup, left the belt on the ac when I removed the serpentine belt. I'll replace the water pump and go from there. Thanks!

corn18 · August 19

Ok, replaced the water pump and the squeal seems to have gone away. Will have to wait until tomorrow morning to know for sure but I am hopeful.

corn18 · August 20

Well, the squeal is still there. Will replace power steering pump today.

corn18 · August 20

Replaced the power steering pump. The power steering fluid was very dark and smelled bad. Steering is easier now as well. So maybe that was the problem all along. Will see tomorrow AM when I start the engine cold.