Like "Helga She Is Fine " states below. When engine is cold, exhaust gas leaks from the spaces in the exhaust system and produce the noise but once the engine gets warmed up, iron expands and the space gets closed then noise disappear... Is this possible?

>>When the bolts stretch out and the heads snap off it allows exhaust to shoot out of the gap between the block and the exhaust manifold rather than flowing all the way through the exhaust system.

 

OP, did you ever talk to anyone else about this yet?

I'm curious to see if you can just get this fixed for $200 ish & save for that Duramax later.

 

Sure sounds like a broken manifold bolt to me. I had two in my 04 and 1 in my 08. Tick, tick, tick, tick, until engine is warm then pretty much nonexistent. Let it cool down, start it back up and tick tick tick. Very common problem. Lousy bolts, the heads snap right off.

To fix it can be costly. I fixed my 04 myself and what a nightmare. Luckily I found a company that makes a bracket that will fix the issue for much less. Much easier too. Will only work if the broken bolt is one of the corner bolts. Most likely yours is the rear driver.

Here is the company. Put this on my 08. http://www.kralautoparts.com/

The 6.0 is tough as nails and should last no problem for a long time. As someone else stated it's a 300000k mile engine. I'd bet money your issue is the Exhaust bolts.

 

Hey everyone thanks again for your help & advice; I'll let you know how I go.


I haven't been able to get a 2nd opinion it's been in the shop since I made my first post here. After reading about the exhaust manifold I went straight to call the dealer to have them check that first. They checked and assured me that the noise is coming from 'deep inside the engine' and no way could it be the issue as I described it (and I used the description here verbatim)


I got their reassurance that they would make extra sure that it was not the bolts/exhaust manifold - they surely wouldn't rip me off like that if it was not going to fix the noise, right?!?


So as much as I'd prefer to keep the money in my pocket, I really want my beautiful H2 back and able to resume duties so will have a new power plant.


I've had the car since 2008 (it's a 2007) and she has always been looked after, regularly serviced with everything the dealer told me I needed (as you can tell!) and used as a daily driver for my wife with trips off road into the Sierra's when we can get away for camping or snow fun but even then not thrashed. They want $2,500 core charge from me if I want to keep my original Engine I wonder if I should do so maybe it's worth it for resale?


--m3cruz

 

You do not need your original engine. It's not a Hummer specific part. It's just a 6.0 GM motor and there are 1000's of them out there.

 

Thanks calif_phil and in hindsight it'd just be another thing filling the garage!

So has anyone out there had a new Engine in their truck and if so what is the best run-in approach you would recommend?

I've always bought 2nd hand myself but I recall instructions about keeping the RPM down for a certain number of miles or similar used to be the recommended approach

--m3cruz

 

Drive it normal, don't tow with it for the first 1000 miles and maybe change the engine oil after the first 500 miles and put in full Synthetic.