I am thinking about buying a 2006 hummer h3 with the 3.5L. We have actually already purchased it but I am deciding weather or not to take a loan out on it and keep it. Anyway it is in nice shape and clean with 118,000 miles. I have no clue what has been done to it in the past because it was bought at a auction. Now to my question. It runs fine and never seems like it has a miss in it. But the service engine light comes on and says multiple misfire and at one time it showed cam sensor. I know it could be other things but if it is the cylinder head will it ever really hurt anything? How much will it cost to fix it if I do the work myself? Also will the 3.7 liter work in a 2006 hummer? I love the hummer and I don't really want to pass it on down the line so I am trying to get and idea what it will cost and what is the best fix. Thanks

 

I am a mega mechanical noob so I can't help ya, but from reading other threads about this issue I can say thay it seems like an expensive fix.
I have the 2006 h3, 64000 miles. No head issues yet.

 

You would realize it had the valve seat problem if it had one. You need to look to see if your 06 is within the Vin # range for that problem. If I were you (not knowing vehicle maintenance history) I would search around for how to clean the MAF, Throttle Body, and change the spark plugs.

From an old post of mine:
"The S/Ns affected is any 2006 H3 lower than 287591 .... the first one started with 100,001, your truck build date will be Nov. 06 or earlier. Not all have the problem, but some could. The head issue affected not only the I5, 4s and 6s were subject to the same issues. Call GM with your vin# and build date (from the sticker in the driver's door jam) and ask.

Just in case you're gonna say, wow they didn't even build that many 3s? The VINs are assigned at the same Shreveport plant building Colorados and Canyons. Their VIN sequence unit #s are mixed in and subject to the same TSB re: the head/valve issue.

The recall and extended warranty was for very early 2006s, those with the 3.5L L52 Motors built before March 31, 2006. That is not to say some 3.7L LLRs have never had a valve or head issue. All the Atlas motors built since 4/1/06 have the new hardened valve seats."

 

Thanks for the replies. It was built in 8/05. I have already cleaned the throttle body and looked at a couple of the plugs and checked the gap. They looked fine but I will eventually replace. I also put a new cam solenoid/actuator on because I took it out and one of the screens was missing. You can still tell it has a slight miss by the sound of exhaust at idle. I have driven it about 40 miles after messing with it and luckily the light has stayed off.

 

I have a buddy with a very early build like you. He has replaced the new cam solenoid/actuator a few times in it's 160,000 miles. Came to find out just a few days ago that the timing chain is stretching and causing the new cam solenoid/actuator to throw a code. No an easy fix but not a deal breaker.

 

Thanks. I have driven it around a little more and let it idle a few times and the light has stayed off. Hopefully one of the things I did happended to fix it. I have a feeling that the light will come on again though because it still doesn't idle the smoothest. Guess I will keep my fingers crossed.

 

I5s are not inherently balanced, they do vibrate more than a 4 or 6 at idle, nature of the beast. Just an FYI.