Newbie question-

I am looking at a 2007 6spd manual 5.9 325hp Quad Dually and it is noticeably smoother and a LOT quieter (exhaust) than the earlier 5.9 engined vehicles I've test driven.

Is there a reason for this (like a way-more restrictive exhaust)? Does the 2007 5.9 have DPF (or is it only present in the 2007 6.7 engine)?

Are there "Best Years" for the 5.9 liter engine w/ regard to reliability and fuel economy?

Thanks-
Bob

 

The DPF is on the 6.7 there may be a little bit more emission stuff on the 07 over my 06, mine was pretty quiet when new but she is a little louder now at 60 thou.

 

my 07 is exactly like my 06 other then different trim level its the same

 

The 5.9 between 06 and 07 is exactly the same, but any year of the 5.9 is a great year. Are you sure this truck has a 5.9? or when you say it's "a lot" quieter than the earlier 5.9's do you mean that towards the non-common rail engines?

 

Compared to the other 3rd Gen 5.9s ('03, '05 models) I have driven it's almost silent. The other earlier ones I've driven sounded like "big rigs" with even in the well sound proofed Laramie interior, but the '07 is so quiet even running through the gears (where the earlier ones sounded sweet), it almost sounds like a gasser it's SO quiet. At 60mph, you cannot hear ANY sounds and can whisper and be heard. I'm talking QUIET.

Yes, the '07 is a 325hp 5.9 (that's right off the factory sticker on the valve cover), w/ 69k miles.

Bob

 

yea mine was quiet till about 25k when the motor started breaking in

 

My 07 is quieter than my buddy who has the same 07 truck. My 05 was quiet as-well.
I love the rattle of the old 5.9 they almost sound like a computer buzz. I wouldn't want one though.

 

Actually, I meant the exhaust loudness.
The engine is quiet, but the '07 exhaust I drove was like a passenger car vs. the "open pipe" sound of ALL the earlier models ('03-'05).
None of the 3rd gen 5.9s engines themselves were very noisy at all inside compared to my present Powerstroke.

Bob

 

Noticeable difference is the headlights and badging. Everything else is the same.

 

Hmm, you got me then.

 

Headlights should be the same, but you are correct on the badging.

 

06 was the only year to have lamps on the bottom of the housing. Also, they changed the tail lamp housing style.

 

Mine was quiet until I bombed it...

 

Mine was too......

Get rid of that long round metal can between the cat and the tail pipe.

It will give it a nice rumble.

 

Should I assume that pre-'07 models had very free-flow mufflers compared to later ones?

I put a 4" system and free-flow muffler on my Powerstroke and I didn't gain a single extra MPG, would it be different w/ the Cummins?