Hummer H3 For the Hummer driver who wants the rugged look and off road capabilities of the Hummer, but in a smaller size and with a more fuel economy friendly engine.

Someone please help me identify what this part is called.

Old Nov 24, 2025 | 09:49 AM
  #1  
sante65's Avatar
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Default Someone please help me identify what this part is called.

I need help identi

fiying this part on my cylinder head on my 3.5 vortex. It's cracked and seems to be leaking exhaust.
 
Old Nov 24, 2025 | 02:26 PM
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it looks like an EGR blockoff plate.
 
Old Nov 24, 2025 | 05:26 PM
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A 3.5L Hummer H3 does not have an EGR system, so
an EGR block plate is not needed for this model year. The EGR system is primarily associated with the 3.7L or 5.3L engines in other Hummer models and certain other GM vehicles. The 3.5L engine, used from 2006-2009, does not use an EGR system. What you need to know about EGR block plates
  • EGR plates are for specific vehicles: EGR (Exhaust Gas Recirculation) plates are used to block off the EGR system on vehicles that have one, not the 3.5L Hummer H3.
  • No EGR system on 3.5L H3: The 3.5L engine in the Hummer H3 does not have an EGR system, so there is no component to block off.
  • Possible confusion with other models: If you are looking for an EGR block plate, it is likely for a different vehicle. Common vehicles that use EGR systems include some Chevy, GMC, Cadillac, and Isuzu models from certain years.
  • Benefits of EGR delete (for other vehicles): For vehicles with an EGR system, deleting it can prevent carbon buildup and potentially improve engine performance.
  • Drawbacks of EGR delete (for other vehicles): Blocking the EGR system can increase emissions and may cause issues with engine performance or longevity, as it can lead to higher combustion temperatures.
 
Old Nov 24, 2025 | 06:06 PM
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I thought that port was for the secondary air system, to pump air into the exhaust for emissions purposes? I didn’t think either the 2006 or the 2007 models had Exhaust Gas Recirculation.
 
Old Nov 25, 2025 | 09:27 AM
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If your engine was replaced with one from another 3.5L vehicle, looks like an EGR block plate to me.
 
Old Nov 25, 2025 | 09:33 AM
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My engine is totally stock.
 
Old Nov 25, 2025 | 09:35 AM
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So if the 2006 Hummer does not have an EGR system, then what is that plate for? Mine is actually cracked and I can hear an exhaust leaking come from it. I need to replace it in order to eliminate the leak but I have no clue as to what it's called.
 
Old Nov 25, 2025 | 09:48 AM
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EGR Block-Off Plate





 
Old Nov 25, 2025 | 09:49 AM
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it is a block off plate. you can trace the old one onto a new piece of metal and replace it or use a thinner piece as a gasket and shim it.
wether it is secondary air or egr is moot.
 
Old Nov 25, 2025 | 09:54 AM
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Originally Posted by sante65
My engine is totally stock.
I pulled this image from the 2006 3.5 Engine Schwartz manual. The plate in question is a secondary air system block off plate. This is the only mention of it in the 2006 manual, which leads me to believe that 2006 models did not come with a secondary air system/air pump, which is why your engine has a block off plate.

In the 2007 Schwartz 3.7 manual (not shown), there are sections that say “if equipped, remove the secondary air block plate”, which makes it sound like some 2007 models had a secondary air system, and others did not.

My H3 (2007) definitely has a secondary air system. I don’t want to speculate, but I’m guessing this may have been an addition to some of the later model 2007s, where the earlier 2007s did not have it.

Either way, it sounds like that plate is standard on 2006 stock engines.



 

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