Sometimes they leak due to the flange plate being warped.
I suggest taking the manifold off, checking if the flange is flat (we cut my flange plate in half at the Toyota nationals to relieve the stress - it works a treat and we did some driveway machining thanks to Jamie from JT ), clean it, permatex ultra red silicone, tighten firmly and give it a few hours to cure, tighten the rest of the way to F tight.
Sun, 14 November 2004 23:30
), clean it, permatex ultra red silicone, tighten firmly and give it a few hours to cure, tighten the rest of the way to F tight.
