3.0L Duramax Towing?

[BobHolthaus]

Just did 580 miles from St. Louis to north of Green Bay Wisconsin. 2023 Denali with max tow and air suspension. Pulling my 5200 lbs boat. Had cruise set at 80 mph the entire way, one hand on the wheel. Not a single issue of any sort, not a sway, nothing, even blowing by 18 wheelers. This thing tows like a dream. Like the boat wasn’t back there. Pic is from last night when we stopped; I think we averaged about 10.5 mpg at 80. Today we did 82 for about 3 hours as well.

We did go through a half a tank of DEF though at 333 miles. That was surprising. I had topped it off before we left. I had the same experience today at 82 mph for 3 hours (not a full half tank, but a lot!)

 

[MrMike1289]

Just did 580 miles from St. Louis to north of Green Bay Wisconsin. 2023 Denali with max tow and air suspension. Pulling my 5200 lbs boat. Had cruise set at 80 mph the entire way, one hand on the wheel. Not a single issue of any sort, not a sway, nothing, even blowing by 18 wheelers. This thing tows like a dream. Like the boat wasn’t back there. Pic is from last night when we stopped; I think we averaged about 10.5 mpg at 80. Today we did 82 for about 3 hours as well.

We did go through a half a tank of DEF though at 333 miles. That was surprising. I had topped it off before we left. I had the same experience today at 82 mph for 3 hours (not a full half tank, but a lot!)

Nice! Yeah we blow through the DEF when we tow. Learned the hard way when the system suddenly told me I was critically low in the middle of no where LOL luckily we found a gas station that carried it fairly quickly.

 

[steiny93]

Used a quart in 1400 miles both last and this year.

Are you seeing oil consumption when not towing?
Are other seeing similar consumption? I'm not seeing the same behavior.

 

[altona]

Yes, daily mix of highway and local is about a quart every 1500 miles

 

[BobHolthaus]

Oh boy, I didn’t check the oil. I don’t think I’ve checked oil in my cars for the last 10 years (not kidding). These things are really taking a quart every 1500 miles?

Note: i oil change to the specs; this isn’t because of ignorance. I didn’t think newer cars really needed to be checked, but if someone is telling me to do it, esp while towing, I’ll be sure to do it.

 

[MrMike1289]

Oh boy, I didn’t check the oil. I don’t think I’ve checked oil in my cars for the last 10 years (not kidding). These things are really taking a quart every 1500 miles?

I haven’t personally experienced oil consumption. Honestly I haven’t checked? But after 34k miles and maybe 5-6(?) oil changes, no one has expressed concern with the oil level. Not sure if this is normal? However now I’m curious to check though

 

[Rangerdeepv]

That is going to be a hard sell for me. Rule of thumb is keep total trailer weight to under 75% of the top rating. Have owned a couple vehicles in the past where the trailer towing was near the max towing capacity and it was white knuckled to say the least.

 

[BobHolthaus]

I checked the oil; no loss at all over 1200 miles of towing.

DEF was crazy: gauge showed 50% and then 10 minutes later we got the “132 miles left” warning. I took it down too .4 gallons in the DEF tank. Plan on getting fuel at truck stops if possible while towing, as they have DEF “on draft” as my GF says.

 

[Geotrash]

That is going to be a hard sell for me. Rule of thumb is keep total trailer weight to under 75% of the top rating. Have owned a couple vehicles in the past where the trailer towing was near the max towing capacity and it was white knuckled to say the least.

This has not been my experience with our ‘07 or ‘12 XL Denali’s. They are rated for 7800 lbs and I’m pulling a 7500 lb camper plus kids and dog. It’s extremely stable and I’ve pulled it all over the mountain west and up and down the east coast with no problems. I’ve made some modifications to the cooling system but that doesn’t do anything for handling stability. In my experience, it has more to do with WDH hitch setup and loading than anything else. These are a great towing platform.

 

[MrMike1289]

I checked the oil; no loss at all over 1200 miles of towing.

DEF was crazy: gauge showed 50% and then 10 minutes later we got the “132 miles left” warning. I took it down too .4 gallons in the DEF tank. Plan on getting fuel at truck stops if possible while towing, as they have DEF “on draft” as my GF says.

This was exactly our experience. On longer trips we now bring a few boxes of DEF just in case!