It it worth going with a 5.3?

c good

Original poster
Member
Dec 8, 2011
521
I currently own a meticulously cared for by me... 2002 Envoy SLT 4x4. 4.2 Atlas Vortec. Excellent condition. 180 k miles, 3.42, no G80 diff. I pull a 18ft Sea Ray with no problem. I might be buying a 17-20 ft travel trailer. Around 4000 lbs.

I found a 2007 Trailblazer, 5.3 Vortec, 120 k miles, 4x4, 3.42, with the G80. Wondering if it's worth making the jump up to the Trailblazer. Asking price is $7500.00
 

linneje

Member
Apr 26, 2012
404
I currently own a meticulously cared for by me... 2002 Envoy SLT 4x4. 4.2 Atlas Vortec. Excellent condition. 180 k miles, 3.42, no G80 diff. I pull a 18ft Sea Ray with no problem. I might be buying a 17-20 ft travel trailer. Around 4000 lbs.

I found a 2007 Trailblazer, 5.3 Vortec, 120 k miles, 4x4, 3.42, with the G80. Wondering if it's worth making the jump up to the Trailblazer. Asking price is $7500.00
I have a 2003 5.3L, it stills pulls my 5400 lb dry weight travel trailer (31 ft). No problem. But your actual weight will be nowhere close to your dry weight, so I would make the upgrade, as long as the '07 was well maintained. Just my thoughts.....
 

Reprise

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Jul 22, 2015
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If you weren't towing (and potentially towing more), I'd say stick with what you have.

I have the same year / engine as linneje, in a LWB with 3.73s.

I pulled a 24ft (tip/tail) trailer with it a couple of years ago. 4000lb dry, so near 5200 with batteries, propane, gear, etc. With a weight-distributing hitch & anti-sway, along with a trailer brake controller.
On the flats, it towed as one -- a really nice match. It *did* struggle, once I crossed the Missouri river and headed up in elevation. But I eventually got to 8000' elevation with it, and outside of going a bit slow up grades, I felt safe with that load.

I decided I'd trade in my 24ft for a 29ft, which came in at 5300 dry (plus my batteries, gear, etc., so probably close to 6000lb (the '03 LWB in my config is rated for 7000lb). Picked it up in Eastern Pennsylvania, and drove it back home to IL. First thing I noticed was that I needed to bump up the TBC by +1 in the settings, as I felt I was being pushed when coming to a stop. The other thing (as I crossed the Alleghanies (sp?) with it was that I wouldn't want to pull any more weight than what I had (e.g.; I knew I'd never go for that last 1000lb -- which isn't a good idea, anyway). So... that's what brought me to the Sierra I have now.

Anyway, I know that's not truly apples - apples comparo, but maybe you'll find it helpful.

From what I've seen, the 4.2L guys don't like putting more than about 4500lb max behind their truck. Personally, I'd give it a try with the RV trailer, as long as you're set up correctly (WDH, TBC) Especially if you're not going up mountains with it. Then judge if you want to make the spend for the engine. The 3.42 gear isn't the best for towing, and you likely know that. But since the new truck is 4x4, you'd need to swap f/r, or ditch the front diff, if you wanted to swap gears. With your current, you only have to worry about the rear diff (and that might be the way I'd go, if I were in your shoes -?) Not that there's going to be a *ton* of difference between 3.42 and 3.73 -- but it'll definitely help get you moving more easily (and if this is a dedicated tow vehicle, you could go bigger -- maybe even 4.10, depending on what diff you have). But you'll be running about 2000rpm at 55mph with 4.10 (which is in my Sierra).

The one big thing the V8 will have is that there's a ton of aftermarket support for it -- want a tow cam, etc.? No problem at all. You have your pick of many options. But if I'm spending $7500 to acquire the vehicle, I don't want to put more into it on top of that (both in $ and in time), but that's me. And although I say that, I got the Sierra 6.0L, and promptly put a whole new front suspension on it, along with doing the cam / heads. (i.e.; I spent a ton on top of the acquisition cost, myself). But I love the truck, so I don't cry too much about what I've spent on it, as now I can go anywhere with it (as soon as I get the A/C working! LOL)
 
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Mooseman

Moderator
Dec 4, 2011
25,177
Ottawa, ON
Here's my experience. Used my 07 TB 4.2 and 3.42 initially to pull our first camper, a 22' 5200# loaded hybrid. It towed it OK except when we would get any kind of grade, it would drop to 2nd and stay there until over the top. Definitely not a happy truck. It didn't get hot or anything, just clearly underpowered. I then switched to using the 06 Saab with the 5.3 and 3.73 and it was much better suited. Towed with this setup 5 or 6 times and no issues except one day it was running a little hotter than usual due to 34c temps and A/C running but didn't overheat. think it was caused by the Hayden fan clutch.

Traded up to a 25' 5500# dry/7500# loaded regular trailer. It towed it empty when we first bought it so mostly dry and no issues. On our first trip, we weren't that loaded however, the engine in the Saab decided to start knocking on a long hill climb in 2nd. I was flirting with the max tow rating of the truck but, in all honesty, that engine always had a noise that I always thought was piston slap. Wound up having to buy another truck in desperation, an 08 Avalanche 6.0L and 4.10. This truck is way more suited to tow this rig.

For your situation. If that 4000# is dry weight, then loaded, at minimum, it will be 5000#. Some have successfully towed with a 4.2 but had overheating issues when having to do long hill pulls so had to redo their cooling systems with all original OEM parts. When I was towing out first camper with the 5.3, it was better. The truck you have found has 3.42 gears. Not the best but would still be better than the 4.2. The only thing that would make the 4.2 more viable is 4.10 gears.

Another consideration is that the SWB 4.2 is usually backed by only an 8.0" rear diff. The 5.3 is always equipped with the 8.6" diff which will make it last much longer in hard use. And also with that 5.3 you automatically get the bigger front brakes.

I'd switch to the 5.3. Better to have too much than not enough.
 

TollKeeper

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Member
Dec 3, 2011
8,027
Brighton, CO
I personally swear by the V8. Although I think some might think I am bias as I have never owned a I6, but did rent a few (and towed with them, but dont tell the rental companies).

The biggest complaint I always have about these trucks is the GU6 3.42. When you can pull all the way up to 85 MPH in second gear, you know its gearing is to low.

The V8, in general is harder to work on. Motor mounts are a pain, tune ups are a pain, etc. But reading thru all the threads here, I believe that the 4.2, although a stout engine, is just inferior in every way.

So much aftermarket support for the LS, so many LS variants to choose from.

All that being said, would I buy a 2007 5.3 model?

NOPE!

AFM/DOD is a no go for me. Even thou it can be tuned out, the system is still present, and if the oil pressure got passed into the wrong passages, you could end up with problems. Yes, you could spend a couple thousand dollars and get the system removed completely, but as the previous poster said, Im buying something to drive it, not work on it, to drive it later. You could do the VLOM mod, with a tune, and supposedly it will completely disable the system.

The AFM/DOD system I compare to the front wheel bearings on these GMT360 trucks. Its not a matter of if, but when.

Find a 04 V8 model, and you will be as happy as I have been the last 130k miles with my 04 Envoy. And dont forget about the kissing cousins (Ascender, 9-7x).
 

Mooseman

Moderator
Dec 4, 2011
25,177
Ottawa, ON
Even thou it can be tuned out, the system is still present, and if the oil pressure got passed into the wrong passages, you could end up with problems.
I think that is overblown by one particular Youtuber. As long as the system is disabled, oil pressure cannot be sent to the DOD lifters therefore cannot fail in the way those lifters do fail when they are deactivated (V4 mode). Taking the VLOM out and busting the seals as well as blocking the oil passage in the oil pressure sender passage is overkill. Just get it tuned out and you're done. That's what I did with my Avy and the Caprice and I'm fine with that.
 

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