i pulled off my plenum to replace the egr valve and i noticed that the machined surface that mates to the runner flanges is pitted. has small tiny pits here and there.have any you guys seen this before? it should still seal up right or is there any way i can try to make it better?

 

It should seal... When i did my intake I ordered polished stainless steel bolts thru Alloy Boltz... I purchased the total kit and I love the allen head over the star... My sons sanded the runners and plenum starting at 120 grit and went to 2000 grit. Then they polished them, it looks awesome...

 

The pits are probably residual from the casting process. Should be no problem sealing. I use a little smear of Sensor Safe RTV on both sides of my gaskets to assure a good seal.

 

I have 2 new old stock map plenum's they all have these small holes.

 

I have a nasty lower intake leak that I couldn't pin point. The corners of the manifold have started to corrode from the coolant..

 

Several years ago, my intake developed corrosion path from coolant to outside - looked like a worm ate its way out in the aluminum! I took it off, filled it with jbweld, sanded smooth and re-installed. I have a new one starting again in another place. At least I know I can fix it again that same way, because the fix has lasted for at least ten years and is still lasting - this is another one starting to appear now - just a slow seep so far.

 

well i slapped it back in there and it passed smog today so it must have sealed, will keep an eye on it with my fingers crossed. thanks.

 

Good news on passing smog. Those who have trouble with coolant eating through your aluminum engine parts: be sure to act quickly resealing the manifold. The longer you let it go, the worse the damage will be. Think about adding Bars Leaks Anti Rust to your coolant after you flush the system thoroughly. It coats the cooling passages and helps prevent corrosion. Also, consider a sacrificial zinc anode to prevent further loss of aluminum.