[SkySoldier]

So I finished blasting 62k miles of shit off the first 4 intake valves, now I notice there is a tiny hole that goes up into the head in each of the intake ports above the valves. Where does this go to? should I be worried about the walnut shells that have probably gone up there? DIY guides said nothing about them.

[sammy_0559]

Don't worry, I've done a million. no one has ever had any issues.

[SkySoldier]

Anyone have an EGR system diagram?
I suspect the holes lead to the EGR system, would be interesting to see if disabling the EGR valve would stop the carbon buildup.

[eric@helix]

Originally Posted by sammy_0559

Don't worry, I've done a million. no one has ever had any issues.

This.

[sammy_0559]

Originally Posted by eric@helix

This.

[SkySoldier]

K i'm not worried. But still curious what the holes are for?!

[JamesM3M5]

You should be worried about them if you have a powerful blaster tool but inadequate vacuum power. It will push walnut bits into the PCV. Not the end of the world, but not ideal, of course. You want to use a relatively large shop vac at the same time you are blasting to prevent the walnut shell bits from working up into the PCV and down into other intake ports.

Those ports are part of the PCV system, and they run up into a channel on the outside of the valve cover. You can see it with the acoustic cover off. If there is a lot of liquid oil coming down from those ports (usually #5 and #6), then you may want to get a new valve cover (comes with new gasket) and/or remove and clean your VC thoroughly with heavy degreaser and water, blow dry, and upgrade the PCV to the Rob Beck PCV valve.