2007 engine does not run like 2006 engine.

[finall]

Just traded in our 2006 H2 for a used red 2007 H2 SE with 11K miles. Real beauty. But does not sound nice. The 2006 engine was very smooth idling, and had strong pull through all rpms.

But the 2007 engine has a noticeably louder and rougher idle. A bit of a growl. Slight vibration clinking noise from under the hood that was not there on the '06. Sounds a bit like an aftermarket exhaust (but it is stock of course). The growl grows when accelerating from a stop with increased foot pedal travel and rpms, until the vehicle reaches about 30mph. Can't see anything.

The 2006 was noticeably quieter at idle, and smoother at all speeds. No growl.

So the first thing I did was change the new oil that the Hummer dealer 2-litre overfilled during a change to synthetic when I finally got the freshly changed over-tightened and siezed oil filter off. Just after they delivered the 2007 H2 SUV to me. Hopefully this screwup on their part did not damage the engine, as it was only driven this way for 50 miles before I got it home.

I am using the same oil, and the vehicles have about the same miles on them. Threw in 2 bottles of injector cleaner into the tank. No difference.

Has anyone else noticed this difference between the 2006 and 2007 models? Is this growl normal, or does the 2007 have something wrong with it? Seems to run fine otherwise. Just more noisy.

Did anything change from 06 to 07 in the engine, tranny, or exhaust that could be causing this difference?

Help!! Anyone who owns or have owned both an 06 and 07?

Help!! The truck has an appointment with the dealer on Monday for this growl, but I would like to avoid taking it in for exploratory surgery if it is not needed.

[HUMTECH]

They should be the same other than the 07 may have different calibration updates which the 06 didnt have unless it was recently updated. As far as the oil filter being over torqued, no damage not to worry there. Lots of lube shops will do that just to cover there butts. If it was not leaking, no problem. Do mention your concerns with the service manager or shop foreman and have them addressed, if nothing else it will be on file if problems do arise.

[finall]

Hi Humtech,

Thanks for the speedy answer!

Should I ask the dealer to flash the latest update to the 2007 computer, just in case something has gone sideways with the present calibration?

The 2007 has a definite growl (louder, rougher and deeper sounding idle) than our 2006 had at idle. The difference between the '06 and '07 seem to disappear above 1000-1200 rpm.

Are the H2 engines hand built, or for some other reason is there a difference from engine to engine that could account for the different sound tone of the engine? The engine vibration changing with RPM is also different (more pronounced on the 07).

And yes, I hear you about the dealer covering their butt on the over-tightened oil filter. But I figure a newbie did the oil change. I only tighten hand tight. The guy overfilled it too, and this is pretty hard to do on an H2 due to the hole markers in the dipstick end, which clearly show you how full it is.

[HUMTECH]

Def hard to overfill, not smart on their part. As for the calibrations the 07 likely(maybe not) has the latest software already. I myself have never noticed any difference in the model years. As far as i know all engines are assembled by hand(dont think a robot could do it). A slight change in exhaust routing can cause significant changes in percieved noise. We have run into many trucks that after hours of exhaust tuning with weights hung in various spots and slight mods to satisfy customers yet the next truck built the same way has no problems. Tough call and will likely end up as a nff(no fault found) but as i said at least your concerns will be on file if it turns out to be something more

[tomp]

07 has 3.5" exhaust versus 3" on previous years and uses same engine

[finall]

Hey Tomp!

Ok, a different diameter exhaust would definitely account for this sound difference! Good call.

Now, I am curious. How did you find out this difference? Did you measure the pipes? If so, what prompted you to do this? Or did a muffler shop discover this for you on a custom exhaust install? I would sure like to know.

I have been cruising the Internet to see what changed from 06 to 07, but an exhaust change is not mentioned anywhere......

[timgco]

Originally Posted by finall

Hey Tomp!

Ok, a different diameter exhaust would definitely account for this sound difference! Good call.

Now, I am curious. How did you find out this difference? Did you measure the pipes? If so, what prompted you to do this? Or did a muffler shop discover this for you on a custom exhaust install? I would sure like to know.

I have been cruising the Internet to see what changed from 06 to 07, but an exhaust change is not mentioned anywhere......

Good call Tomp.

There was a thread on this a while back. My 06 to 07 was a little different. This one rattles (heat shield), but is slightly louder than my 06 was...befor ethe CORSA exhaust that is.

If you are getting a rough idle, it may need an update/ calibration. I'd take it in and have them plug it in. It should be runing rougher than the 06.

[MONSTERMATT]

LEMON

[mdoyle]

I can't believe nobody focused on the 2 liter overfill, that's a hell of a lot of extra oil and could cause hydraulic effects damaging things; like bending the connecting rods for one.

You could also end up with a host of problems in the PVC system and associated emmisions components.

Did you drive it prior to the overfill and notice a difference in sound and performance?

It's going to be an uphill battle since damage from a stupid mistake like that isn't as easy as pointing at a dent and saying, "here's the problem".

Good luck.

[finall]

Good question.

The oil change was done a couple of days (less than 100 miles) by the dealer, prior to us test driving it and buying it. I am not sure if a 100 miles would be enough to damage the engine?

The 06 engine sure pulled stronger and was quieter. I will ask dealer to flash the PCM or whatever, to make sure timing and firing is correct.

[HUMTECH]

Did not know they changed the exhaust diameter. Learn something new everyday i guess

[Rico001]

Originally Posted by MONSTERMATT

LEMON

Hey Matt awhile since we have seen you here.
Have you got a new Hummer yet?
~Richard

[tomp]

http://www.*******club.com/forum/viewtopic.php?f=3&t=6125&st=0&sk=t&sd=a&hilit=exha ust

[finall]

Hey Tomp,

Thanks for the link! Usefull info. Basically confirms that the late 07 exhaust is really an 08 exhaust. That may explain the growl I am hearing versus the 06.

Anyone have an 07 and 08 H2, and do they sound different or the same?

[finall]

FINAL SOLUTION:

Ok, our 07 SE SUV came back from dealer's shop, and they say that it sounds "normal".

To compare, they brought out a brand new 07 SUT SE for us to test, and it does sound the same idling and during a test drive. Same vibration stopped at idle, when you touch the tires. More vibration off the front right tire than the rest. Same vibration, most pronounced at 1500 rpm and light load when driving.

I did not realize that the 06 was so much quieter and smoother!! The larger diameter pipes on the 07 create quite a roar. The 07's are WAY WAY rougher than the 06s. They apparently "improved" the vehicle. DUh?

On the positive, it gets about 1L/100km better gas mileage with the larger pipes.(= about 2mpg?)

Learn something new everyday with these vehicles!