[senorschmidt]

I was underneath my suburban today (2008 2500) and noticed that it has 2 tanks. There is a smaller one that is right above the spare tire which the filler tube goes into, but then there is a much larger tank connected to it on the driver's side. I tried to figure out more info, but have come up empty so far. Why have 2 tanks instead of one larger one? Are there 2 different fuel pumps and sensors? I don't get it.

 

[squatchy]

It’s incredibly simple. There’s only so much room where the tank is. The 2nd tank gives you probably about 1/3rd more fuel capacity, giving you a further range. It’s very common. There are fuel pumps in both tanks, the smaller tank will fill the bigger tank at whatever predetermined level go decided for it to turn on.

 

[senorschmidt]

Makes sense. I guess they had to do that in order to move the spare underneath. In my 96 there was only one big tank, but the spare was inside the cab.

 

[squatchy]

Sounds about right. I know I’ve seen an 02 like yours, maybe they started it in the 00 body year

 

[RayVoy]

Hmmm, never noticed 2 tanks under mine, must take a closer look

 

[xPosTech]

A 2500, Ray. The 6L goes chug-a-lug.

Ted

 

[RayVoy]

A 2500, Ray. The 6L goes chug-a-lug.

Ted

Yeah, I see what ya mean, Ted

 

[blackburb]

Makes sense. I guess they had to do that in order to move the spare underneath. In my 96 there was only one big tank, but the spare was inside the cab.

Exactly. And the 2 on the 800 is still less capacity than the big tank on the 400 was. Something like 38 gallons vs 42. I think the primary reason for moving the spare was so they could add the subwoofer

 

[squatchy]

Haha they couldn't put the sub woofer in the center console like they do with the pickups?

 

[JackE]

So you guys are saying the 6L has as much a drinking problem as my 7.4L? With the wide open roads I drive on, the lack of civilization around here, and 12 mpg, the only thing I can't pass is a gas station!

 

[RayVoy]

It's only about 12% bigger than the 5.3, shouldn't be much harder on gas.

A buddy has the 6 in a 2010 and he thinks the mileage is good.

 

[xPosTech]

It's not just the 6L. It's also the weight of the truck it's in. The 2500 is weighed down with more robust frame, suspension, rear axle, wheels and tires, transmission and weight of the extra fuel. It all adds up to lower mpgs.

Ted

 

[squatchy]

I bet you couldn’t pass my duramax while I passed up that gas station you had to pull into . Tho I do with the trucks came with bigger tanks too. 36 gallons is ok, but a titan fits in the factory location and is 57 gal for my truck (crew cab short bed). 21 more gallons in the same spot. Add that to the 50 gal auxiliary in the bed and I would have about a 1900 mile range on a fill up

 

[squatchy]

It's only about 12% bigger than the 5.3, shouldn't be much harder on gas.

A buddy has the 6 in a 2010 and he thinks the mileage is good.

Idk about newer stuff but I had a 00 5.3 and my neighbor had an 01 2500 light duty 6.0 and I got about 5mpg better than he did. His son has an 02 2500 hd and it gets about 2 less than the light duty

 

[RayVoy]

Idk about newer stuff but I had a 00 5.3 and my neighbor had an 01 2500 light duty 6.0 and I got about 5mpg better than he did. His son has an 02 2500 hd and it gets about 2 less than the light duty

My buddies was the 1500 HD and as Ted pointed out, the 2500 is heavier