LastViceRS

Do you guys notice more of a tendency for aluminum intakes to leak at the coolant crossovers? Seems like I never had a problem like this with cast iron manifolds, but my last two cars have had aluminum and I've replaced gaskets on both. Is there something more than luck to this? And can I do anything different to seal them better? Thanks in advance for any replies.

Ward

iTrader: (1)

Well, the intake will expand as it warms up more than an iron one, and it will also expand at a different rate than the heads/block, unlike an iron one. But it shouldn't be enough to make it leak. I've had no problems with my performer. I use black RTV on both the intake gasket faces, as well as the head faces. Also, all my intake bolts have lock washers on them, which may help a bit. Here's a tip though, don't use the crappy rubber front and rear intake gaskets which come with intake gasket sets. I've never had any luck with them, they always leak after a month or 2. I just use a thick bead of black RTV on the front and rear seals, between the intake and the block.

LastViceRS

Yeah, I knew about the different expansion rates, but I hadn't considered that here. I've never used RTV between the manifold and block, although I've heard quite a few recommendations of it. Come to think of it, I did once use Ultra Blue on the pitted sealing surfaces on the stock aluminum manifold on my last car. That one did seal. Thanks for refreshing my memory.

Danno

I have seen it a lot. It has everything to do with expansion/contraction rates. It is a problem not just with our cars. Ideally one should go back after a couple of heating/cooling cycles and retorque the fasteners, but try to do it with a TPI. Left alone after a couple of years the fasteners get to the point of almost being only finger tight. Any time different metals are joined together this problem exists. Thats why I am not a fan of aluminum heads. When you have torque to yield specs it scares me. My recommendation is to use Fel-Pro printoseal gaskets. I also recommend doing it over a weeks time. Torque to spec, let it sit and redo it over a few days. I have seen pro's replace them only to see it come back in a few months. You are also right, I have never seen it to the extent with the cast iron ones.

VERTIGO Z28

iTrader: (1)

I use Indian Head on all the intake manifold bolts. Coating them whit this stuff completely seals the threads, which is where most of the seepage occurs. Since my motor builder clued me in on this I have not had a leak since. Good luck bro:lala: