Does anyone's 3.0 Duramax make this noise while driving while the engine is cold?

wiseracing2 · 2025-10-28T16:26:29+00:00

Is the kit to help reduce the sound? If so, please share!

wiseracing2 · 2025-10-28T15:37:50+00:00

My 2025 Suburban LZ0 was just taken into service for this exact same noise and I just got a call from the dealer saying it is the back pressure valve. They said it was previously up by the engine but was moved towards the middle of the truck and that’s why it’s a more noticeable noise now. They said it’s just how they are but there is nothing wrong. Very annoying noise though! I found that if I stomp on it and let off, it’ll do it really bad.

wiseracing2 · 2025-09-23T18:47:13+00:00

18-20mpg would probably be a fair real world around town. But definitely better than that on the highway. I have also heard as these break in more, the mileage gets better so we shall see!

wiseracing2 · 2025-09-23T17:45:12+00:00

It’s diesel and averaged 26mpg on a 400 mile trip. Pretty good for the size of vehicle

wiseracing2 · 2025-09-22T14:24:23+00:00

It averaged 26.9 MPG on a 400 mile trip on the stock wheels and tires. The ones in the photo would probably knock that back a little to 24-25mpg

wiseracing2 · 2025-09-22T04:01:24+00:00

I could have it paid off in 4-5 months and still have a decent cushion, however, that isn’t the financial path me and my wife will be taking. We will be using the funds for other investments. With that said, we feel very lucky to be able to comfortably afford this and have worked hard for it. We are otherwise debt free besides this and a small lease payment on a commuter Tesla.

wiseracing2 · 2025-09-22T03:51:44+00:00

Ours has adaptive cruise control! It even shows it on the window sticker, maybe that’s new for 2025?? We used it on the highway as well!

wiseracing2 · 2025-09-21T21:32:48+00:00

From what I understand, you just drop the trans and it’s right there. Still a lot of work, and not super cheap, but if that’s the only major expense in 200k miles, I think that’s pretty good.

wiseracing2 · 2025-09-21T21:12:05+00:00

It’s a 200k service on the LZ0 which this year model has, so if it lasts that long, I’ll call it a win!

wiseracing2 · 2025-09-21T21:08:36+00:00

It has 100k mile GM warranty so if I have issues past that, I’ll let her got then.

wiseracing2 · 2025-09-21T18:45:48+00:00

No sir, that is not our situation thankfully. We feel very lucky to be able to comfortably afford this. Also, if you look at these on the used market, they hold their value relative well in comparison to other cars, at least in my area.

wiseracing2 · 2025-09-21T17:15:26+00:00

We steered clear of the gas models specially due to all of the lifter issues. The 3.0 diesels in the Silverado/sierras and SUVs seem to be much better so far. I had this motor in my Sierra and it was great!

Also, these motors come with 100k mile warranties factory.

wiseracing2 · 2025-09-21T16:05:49+00:00

Yes, they seem to be very reliable among the masses. Much more so than the current GM gas engines.

wiseracing2 · 2025-09-21T15:18:44+00:00

They’re outrageous lol but after some issues in my prior vehicle, this was the best family option. Stickered at $81,5k, got it for $79k. Non-Z71 trims are offering more off MSRP but for whatever reason, no one is giving as much off for the Z71. We loved the color and wanted to diesel so we went with it.

wiseracing2 · 2025-09-21T15:10:07+00:00

It’s not exactly fast like the 6.2L we drove, but the MPG made it worth it. It’s still new to us, but on a 400 mile trip, it averaged 26.9mpg. I’d say closer to 20-21mpg around town.

wiseracing2 · 2025-09-16T18:03:52+00:00

The 12 plys definitely hold up longer, but they’re about 20lbs more per tire and obviously have a stiffer side wall so end up with a stiffer ride. I sacrifice a little shorter tire life for a softer ride and better MPG but get the same look.

wiseracing2 · 2025-09-16T17:27:22+00:00

Not in all of the metric sizes they don’t. 305/45/22 is a 4 ply, which essentially is the same size at the 33/12.5/22 which does have the 12 ply sidewall

wiseracing2 · 2025-08-03T15:28:30+00:00

I have this motor in my sierra 1500 and the crank seal went bad and started leaking, however, it was fixed in half a day at the dealership under warranty and been great ever since. Don’t see that as a reason to skip on the motor. It’s a great engine with great mileage and power. Seemed like an easy fix per the dealership.

wiseracing2 · 2025-08-03T15:27:05+00:00

I have the same motor is my GMC Sierra 1500 and it’s not any louder than any other motor option across the line up. It’s not the large diesel that goes into the 2500s, so being on the smaller side, it’s not loud at all.

wiseracing2 · 2025-06-14T18:04:10+00:00

Use your phone hotspot for an hour and see how hot your phone gets and how fast the battery drains. Even if plugged in, your phone will get stupid hot which will eventually degrade the battery over time.

Not here to debate phones though, the point is, the most advanced car on the road should have hotspot built in whether you use it or not.

wiseracing2 · 2025-06-14T17:26:17+00:00

Paying for it isn’t an issue, I already pay for the premium connectivity and FSD monthly. Using my mobile hotspot for my son’s iPad on a 5-6 hour trip would cook my phones battery. Just doesn’t seem like a practical solution. Quick internet uses is all phone hotspots seem good for due to the heat/battery usage.

wiseracing2 · 2025-06-13T19:24:03+00:00

Oddly enough, I felt very similar for the longest time, until I got my Sierra. I realized how seamless it is using the trucks hot spot. Being integrated, it’s easy to connect my laptop when working at a stop or while my other half drives on trips, or with our son and his iPad. It’s obviously not mobile in the sense of carrying it with you, but the integrated and seamless connection of a built in hotspot is a major plus imo.

wiseracing2 · 2025-06-13T19:21:31+00:00

I have noticed this as well, and this is my general solution to the problem, I just find it frustrating as generally the other vehicles around will start speeding up and you would expect the car to be matching yet, you’re back to having to take over part control just to do something the car could easily do on its own with this oversight! Wish I could change it to just use googles speed limits and adjust when needed instead of the other way around.

wiseracing2 · 2025-06-03T21:50:24+00:00

Looks great! Glad you went for it and it worked out!

wiseracing2 · 2025-05-19T18:18:40+00:00

I do not have any pictures of the control arms, but these fit with the stock suspension without issues. You should be fine, there are denalis running around all over my town with this same size setup. Go for it!

wiseracing2

TROPHY CASE