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Cylinder Head Problems - 3.7L specific only!

107685 Views 105 Replies 47 Participants Last post by  ChecCol2008
Chime in if you have had issues with your cylinder head on the 3.7L engines only.

We are not interested in the 3.5L issues, we all know them well.

Chime in if you have some experience/input on this subject.
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Add me to the list after having some issue with a PTB from supermod I suspected my truck was fucked up and sure enough today it started the P0305 constantly and I talked to the mechanic at the dealership and he said bring her down wednesday for a leakdown and he said they have to run an injector test just to rule it out per gm's guidelines, but I'm positive and this mechanic sounded positive as well. My trucks a 2007 4x4 Z71 Colorado with 42,000miles.
His wording sure implies that, doesn't it?

Considering I was there during the install, I can say the PTB is not his root cause of truck problems.

Some trucks have factory issues, then the owner begins modifying and amplifying those factory issues. Been there, done that...
Clarity is what this world needs, clarity! :thumbup:

the original PTB we installed was an issue though Gerry it had something electrically wrong with it as it threw throttle position sensor codes constantly the next day after the meet and caused some BS for me. I called supermod and the issue was resolved by him shipping me my original PTB that he had performed the porting service on already, after installing all codes went away and everything was fine. But my point by mentioning the throttle body before was to say that having that better flow with and possibly a slightly different fuel mixture depending on how the sesnors react to it will change the pressure in the cylinder at idle and that slight change was enough to highlight the underlying issue.

And to make sure everyone's clear I have probably had a bad valve seat for a while now and just adding the PTB highlighted the issue IT DID NOT CAUSE IT. My truck still has a Supermod PTB on it now even as it's at the dealer being repaired under warranty(that may ease some of your minds, because unless they stare into it they will not come across a difference) and I support Supermods accessories and services and encourage you all purchase one.
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you don't it's covered because we have a 100,000 mile warranty for the 07's and up
Your 07 should not have a head problem.....GM resolved it in the 3.7's.

no they did not. My truck was a late 07' and had 3 cylinders fail the leakdown at 40K miles
I have 60K miles on a swapped head. Also about 20K miles under boost and no issues.

From what I gather on the little info GM has given the valve seats were machined incorrectly and were damaged by the valves over time. Mine failed at 40K miles.
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