Rattling 2k miles after HG replacement.. but only after sitting 5 mins.

What's the oil consumption been like, historically?

But yeah, you mentioned oily plugs.

 

I assume they lap the valves and checked if it’s all sealed?

 

The proper test here is a compression and leak-down test.

The shade-tree mechanic test above will only reveal a major valve issue, since gas molecules are way smaller than water molecules. I wouldn't expect this test to fail, since a professional shop did the head - they should've already ran that test. Lapping the valves or not!

I'm just spit-balling, because I haven't had one of those apart. Could those new head bolts be slightly out of spec.? If any of those head bolt holes bottom-out; you may think that it's torqued-down correctly.

Oil burn is more than likely sticky piston rings, assuming the head was done correctly.

YMMV

 

Water is too thick. If it leaked through, then you have a large gap.

Use wd40 or other light oil, it's very thin and any gap, it will leak through quickly.

I did do the “water test” and filled both intake / exhaust valves with water and let it sit overnight.. didn’t see any seeping on the combustion chamber side.[/QUOTE]