'07 H3 Starting Problems
 

Ok, I have brought my truck into two different Hummer Dealers, and a Chevy dealer. No one can find an issue with out. At random times when I go to start it I hear a metal on metal clanking noise and the turck struggles to start. There is no pattern to when it happens, both winter and summer, hot or cold start. The last time I brought it in they stated that my starter bolts were very loose and said tighented them and it should be fixed, but a week later its back to the same sounds. I have attached some recordings, let me know what you think.

Re: '07 H3 Starting Problems
 

Interesting. I have the same sound on your #3 recording, on my 2009. Mine keeps trying to start without actually kicking over for a few seconds. But I don't get any of the clanking in your other recordings. Mine is also completely random maybe once a week it will happen. I hope someone knows a fix.

Re: '07 H3 Starting Problems
 

sounds like the starter is going...

Re: '07 H3 Starting Problems
 

I was able to narrow it down to after driving longer than an hour. I recorded it happening and took it to the dealer. They found a bunch of error codes related to the ignition switch. They replace it and so far so good. Keeping my fingers crossed.

Re: '07 H3 Starting Problems
 

X2 Sounds like the starter to me too.

Re: '07 H3 Starting Problems
 

Unplug your crank sensor and check for oil contamination. Check your ecm connectors for coolant contamination. Just fixed one that had both. Messed me up after the crank sensor didnt repair the whole problem and found coolant in ecm connector.