Pulling Sucks--2001 Suburban 3/4 ton--6.0

[OldBlueDually]

Gent's, beyond getting a suburban like I should have with the 8.1, is there anything I can do with my 6.0 to make it pull our camper better in "not perfect" conditions (perfect conditions being no wind, no hills, cool temps)?

I am pulling a 34' (bumper to hitch) tandem axle travel trailer camper. Dry it weighs 5,800lbs--probably 7,000 fully loaded with all our crap. I use a Reese brand trunnion style load equalizer setup on this, and I am running 10-ply tires on the suburban, and camper.

With ANY kind of wind, or hill---this suburban struggles, very badly. I am constantly floor-boarding it to get it to stay at even 45/50mph on a straight level road against any kind of wind. This past weekend coming home with hardly anything in the camper (I never pull it with any water in it either), and bucking against the wind, I was doing all I could to keep it at 55mph. Even then, my transmission temp & engine temp were nearing the red lines and I was about ready to pull over to let it cool.

The tow-haul option is an effing joke!! That heats the living heck out of the transmission, and nearly in the red with engine temp. With no tow-haul it works better.

I am beyond frustrated with how much of a dog this suburban is when pulling in not perfect conditions which is most of the time when we use our camper. Is there anything that can be done to make this 6.0 pull better? If it requires a crap-ton of money, I will just find a suburban with an 8.1. I'd like to tinker with this over the winter if I can.

I have ZERO experience with these 6.0 engines, hence why I am asking you guys. Thanks!

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[squaredeal91]

Are the cats possibly plugged up?

 

[bucket]

Ours does ok, but honestly I haven't used it much to pull around a large windsail of a camper. Other than the brakes, I've always felt that my '78 454 Burb was a better tow rig than our '00 6.0 Burb. However, I've never had a problem with it running hot and the trans always runs cool.

 

[PrairieDrifter]

The 6.0 is a dog. Don't get much out of it over a 5.3 other than less mileage and head gaskets lol.

Im pretty pleased how my 98 k2500 pulls with a 5.7 and 4l80.

 

[PrairieDrifter]

Heads and cam or power adders.

 

[HotWheelsBurban]

We never pulled anything bigger than the 6x12 larger u haul enclosed trailer, but was probably at capacity when we did. The truck handled it well though. This was a 2006 Yukon XL Denali with the 6.0 and 4L65E, AWD and 3.73 gears. That trailer is not much wider or taller than the Denali, so I don't think there was a lot of drag on it. Truck had 255/70-20 Michelin tires on factory 20" wheels, so it sat really stable and handling was great for something this big. And I don't recall issues with performance, and we towed this bigger trailer, fully loaded, with 4 of us in the Denali, to Austin and back, and it's fairly hilly.
I believe the load, 3 people, and trailer (5x8 u haul enclosed trailer) that my '97 C3500 crew cab took on our last swap meet trip was around 9500#, and it did well even though it's just a 5.7.
So maybe your Burb has some issues? Our Denali had over 150K on it, probably more like 175K, when we made these trips. And it got driven daily in Houston, Texas area, by my folks.

 

[Hunter79764]

I also have some experience with a 6.0 in a Yukon Denali XL, but not a ton of towing with it. And I have an 8.1 in a 34' Super C. The LS engines in general want to rev, so feel free to let it as much as practical, but from the sounds of it, seems like something isn't quite right on yours. Plugged cat or other exhaust restriction sounds reasonable.
That said, a tune can definitely help things out, especially on a 2001. These were still generally tuned for straight gas, not the 10% ethanol you're going to find everywhere. I believe yours is the lower compression (like my '04, not like the Escalades that had the higher compression), but you might try a tank of higher octane to see what it does.
If this is going to be a regular thing (the heavy towing), upgrade your trans cooler, especially if you're seeing elevated trans temps.

But to answer the question more directly, I'd plan on a tune immediately to get it back to how it should have been factory, and if I wanted more umph out of it, I'd look at a truck cam and replacement valve springs, even if the cam doesn't call for it, they may be getting weaker if you're over 150k miles. And of course, turbo is always the answer, but obviously a lot more involved.

If all you are doing is using it as a tow pig, you might keep an eye out for an 8.1 and do the swap. I haven't dug into it on these specifically, but I think it would be a fairly easy swap with a minor harness modification and a full retune on the factory computer. I could obviously be wrong though, do your homework.

 

[yevgenievich]

I would say do the back pressure test on exhaust. 8.1l will pull better, but 6.0 should do ok letting it ride higher rpm in 3rd gear. It also might be a gearing issue where it falls out of the right spot. 4.10 gears in the rear help.

 

[Bextreme04]

There's no way it should be that bad stock. My 2011 K1500 Burb with a 5.3/6l80 isn't the best, but it did better than that even when it still had the stock 3.05 gears in it. I now have 4.11 gears in it and it will still pull pretty good in 5th gear with the converter locked and rolling at about 65-70mph even with windy conditions. Engine has no overheating issues and the trans runs cool at about 65 degrees above ambient at those loads. When I pull through the cascades or coastal mountains I usually have to manually pull it down to 3rd and let the RPM come up to about 3500-4000rpm to maintain 55-60mph at 3/4 throttle. Still no overheating or other drama and trans will come up to ~100 degrees above ambient at that point with the converter unlocked. No overheating issues still.

First thing I would do is get a tru-cool 40k cooler out front. You will need two GM quick connect fittings and a 3/8" compression coupling and then it only takes about an hour to install it in place of the tiny stock external cooler. Your 4L80 will really thank you for that. Then I'd start looking at why the engine is a complete dog. When was the last time you changed the plugs and wires? How old are the O2 sensors? If all of those are original... its going to really hurt the power output. Run a couple bottles of cataclean through it. If you have plugged converters, that will help blow the junk out. Connect a vacuum gauge to the manifold somewhere and rev the engine to about 2-3k rpm, if you see the vacuum start around 20in-hg and then start dropping towards 0 while it is sitting there reving... you have a clogged exhaust. Usually because the cats are old and have come apart. This can also cause false knock from the cat parts bouncing around in the exhaust, which will cause the knock sensors to detect detonation and pull a bunch of timing. If you have HP Tuners, you can see and log timing and knock retard and see if that is happening. You could also buy an OBDxPro GT tool and use PCMlogger to see what is going on. That would also give you the ability to tune the engine yourself or even reflash the PCM with the 8.1 engine segment if you ever do that swap in the future.

 

[Grit dog]

Agree, I’d look at the exhaust and make sure it’s not choking the engine. Pretty common slow progressive loss of performance issue with old cars with cats.
I would generally consider that combo to be a bit of a dog and wouldn’t expect it to ever get into 4th gear except going downhill.
But I think performance and the temperature issues you have are somewhat or wholly exclusive of each other.
Have and still do have some old 6.0/4L80 work trucks and overheating engine and trans is never really an issue. Heck used to have a couple duallies with the 6.0. Slow azz turds but no overheating.

Performance wise for the engine, unless just a tune does something, the typical, tune, cam, headers etc is pretty spendy and time consuming.

Bottom line, I’d concentrate on the temp issues and check the exhaust. From a budget standpoint it just gets to be a lot more $ to do any real parts swapping. JMO.
And if it’s 3.73s that doesn’t help matters.
Also concur, not a single LS motor out there that is unhappy with running high rpms for extended periods. Let er eat.

 

[Craig 85]

If you're on Facebook join these groups, it's specific to 2500 Suburban owners. Very good groups, basically the same people in each. People behave very similar to this group.

2500 (3/4-ton) Suburban/Yukon Owners

Suburban/Yukon XL 2500 (3/4-ton) Owners

 

[OldBlueDually]

Thanks gents!! I will hook up a vacuum gauge & also run a can of that cataclean mentioned just to be sure, I will certainly update the transmission cooler either way no matter what.

As for plugs & wires---I have never done them on this rig, yet. Not a bad idea just to start fresh. O2 sensors, not sure how old they are, I'll have the scan tool hooked up to it and get a reading on those to be sure they are behaving properly.

I can also certainly try a higher octane fuel in it also--then lastly I would look into a tune for it. Is there a company/part number someone suggests for a tune?? Is it literally a chip or something?

 

[Bextreme04]

Thanks gents!! I will hook up a vacuum gauge & also run a can of that cataclean mentioned just to be sure, I will certainly update the transmission cooler either way no matter what.

As for plugs & wires---I have never done them on this rig, yet. Not a bad idea just to start fresh. O2 sensors, not sure how old they are, I'll have the scan tool hooked up to it and get a reading on those to be sure they are behaving properly.

I can also certainly try a higher octane fuel in it also--then lastly I would look into a tune for it. Is there a company/part number someone suggests for a tune?? Is it literally a chip or something?

Not a chip. You either find a local or remote tuner that knows what to do with LS engines or you can buy the equipment and do it yourself. Those years have available free tuning software. So you can do HP Tuners for about $400 or you can buy the tool for ~$80 and do the tuning/logging yourself with TunerPro or universal patcher.
https://obdxpro.com/product/obdx-pro-vx-obd2-diagnostics-and-tuning/
You can also do the tuning with a generic ELM327 cable or adapter, but it will be much slower than the OBDx tool.

Higher octane fuel isn't going to do anything for you on an older 6.0... they have pretty low compression for an LS anyways. The thing with the newer engines like this is that they will hide a lot of issues that you would normally notice sooner on a dumber engine. So plugs/wires or small vacuum leaks will often not be very noticeable in normal driving, but the way that the engine is adapting to correct those issues will cause you to have much less power and get worse fuel mileage.

 

[RaisedK5]

I agree with most of the suggestions here regarding tune up parts. When I first got my 05 2500hd, thing ran like a scalded dog. After several years started to loose a step. Did plugs and wires and got way better. Never threw codes. On a trans America drive lost the map sensor. Ok. Replaced that got some pep back. Only occasionally threw a code on long grades in hot weather, hasn't since replacement. Several months later finally started throwing an occasional code on one O2 sensor. Replaced that and she feels like her old self again. And milage is back to where it was in 2012 when I got her. I guess my point is I think I was having sensor issues long before the codes started popping but they only show up if they trigger several times in a row. So do your self a favor and start looking at the tune up parts. After since I changed all mine I towed my Bumper pull (33ft and around 9600lbs) 3500 miles from Los Angeles to eastern Canada and she pulled great. Averaged just under 10mpg and had no problem maintaining 62-67 mph (50-60 in the hills)

 

[backyardgarage]

So I own an 01 Silverado 2500 HD 6.0 and I haul everything but past a gas station. Tractor weighs about 9k with trailer about 3k so right at my limit for the suspension, at least stock suspension. The biggest improvement I made was about 12 years a go I had a computer reflashed by a company called Wait4Me. I also added a cold air tube and exhaust, and that increased my mileage about 1/2 mpg....oh yeah baby!!
I never had a problem towing, and my mileage is always the same towing or not, 9-10 mpg. I did have my transmission rebuilt at 100k and during hot days it will climb while towing but never overheated. Now I do have to run 93 octane due to the tune, but it will pull with no issues. I do also have to say I live in Florida, so my towing is mainly flat land, we do have a few hills, and transmission will down shift if I have cruise on, but I've learned to feather the throttle with the cruise off and it doesn't downshift as much. I've owned this truck since 2002 and as she sits she's at 230k and has a trailer hooked up 90% of the time.
So my suggestion, put a scanner and look at your fuel and ignition. If everything good, find a good tuner and have them tune your truck, also have turn off the TM or at least turn it down. Then do exhaust and a cold air kit, I wouldn't recommend a K/N, I tried their kit and had bag preignition pinging, but that could be tuned out. Good luck

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