Leaderboard

There's only one high pressure oil passage on the top of the gasket. If it's flipped backwards that would explain the leak. It's the topmost oval one. It should match to the top port

I don’t think I’ve gotten H4s of that vintage. 06+ H6 installed years ago, after 135k miles it started headgasket issues last year. Came with two damaged connectors from shipping, not unsurprising for shipped/JDM engines. taped one and never had issues and spliced the other from the original engine. I installed new VCGs and OEM iridium spark plugs…and probably the oil cooler seal, when I installed the engine and never touched the engine again for 135,000 miles except oil and belt.