o4.5 D Max ?

**ed b.** · 09-02-2011, 07:11 AM

Hello. First off I'm new here. I just found this site.
I am looking at a truck with this engine. Everything is stock on it. What can I expect for fuel economy unloaded and hauling a 10,000 pound 5th wheel? I don't hot rod, but I also don't annoy people behind me with a really slow acceleration. It has 133,000 on it. I've never had a diesel but I'm wanting to switch b/c my 6.0 is killing me is fuel cost. Maybe get 12 mph hwy 10 city with it unloaded. 8 towing if i keep it at 60mph on a flat hwy. 5-6 is more common.
Thanks

Ed

**Jameslleary** · 09-02-2011, 08:59 AM

As of right now, the only Duramax available in light trucks is the 6.6...from what I could find on GM`s website. 4.5 is just a pipe dream for now.

**ed b.** · 09-02-2011, 01:33 PM

I should have been more clear. It is the 6.6 engine. The year is 2004.5 it has the lly injectors that were installed in the later part of 2004.

**Jameslleary** · 09-02-2011, 09:25 PM

Well, I can tell you that you will get better than 5 or 6.....From what I have heard, you may see from the mid to upper teens while towing, and upper teens definitely when not. A lot of guys out here in farm country are running Dmax`s with only 1 mod, and that`s the Walker Big Truck Muffler. It keeps the noise down to acceptable levels, but allows the turbo to spool up quicker, aand just plain makes the truck a little more efficient.

**WillDaBeast69** · 09-03-2011, 12:19 AM

if you put a CAI, exhaust, and a tuner on that you'll get a lot more power and fuel economy

**Diesel Dan LB7** · 09-03-2011, 12:29 AM

Originally Posted by willdabest69

if you put an exhaust, and a tuner on that you'll get a lot more power and fuel economy

fixed

**DarkCharisma** · 09-05-2011, 04:44 PM

The truck in my signature is a 2004.5 (LLY) model Duramax. Unloaded I get about 15mpg combined, 70% city (at least), the rest highway. If I go all highway, I can easily get 17-21MPG, depending where I set the cruise, and if there's a headwind.

I haven't pulled very much weight, but I got 13MPG at 65MPH, towing into a headwind with the AC on (110* ambient) with this load:

That's two Yamaha Grizzly's, a Yamaha Wolverine and a Yamaha Timberwolf, with fuel, water, food and gear for 3 days, along with bigger tires/wheels and winches on the Grizzly's.

I really do love my truck. It's powerful, quiet, pulls like a combination of an ox and a quarter-horse. The only problems with this year is the propensity to overheat. I suggest you look into a new mouthpiece (turbo inlet) for this model truck, as it was a factory weak point. I got the Kodiak MP for $90 shipped, took all of 15 minutes to install and did help my temperatures quite a bit. There are also auxiliary radiators available, and you can really use any number of modifications to help with temperatures.

**ksstang** · 09-19-2011, 07:33 AM

I also have a 04.5 Duramax with the LLY. I have CAI, 4" straightpipe off turbo with 5" tip, Programmer, and I'm getting 16-17 around town all day long, and averaging 22-24 on the highway.

**Heavytruck** · 10-02-2011, 09:21 PM

I just bought an 04.5 also. 20-21 hwy...btw has anyone experienced this ordeal with running their truck, then having the upper radiator hose suck closed after it cools down?