Water crossover leaking
 

After I filled radiator with antifreeze I noticed a leak from the water crossover where it meets the head. I used felpro gaskets and all bolts were torqued to spec. If you look at the picture you’ll see how wet the gasket is on the drivers side. Not sure if passenger side was leaking a little. This was leaking without running if that matters. Should I have put RTV around the crossover holes as well as the gaskets?
Thank you.

If you`re not using a factory intake, ditch the orange retainers.

I have never had this problem before but I would think a little RTV let the get tacky and then the manifold SST down and retightened would fix it. As long as the engine hasn’t been run with hat gasket

It’s not a factory manifold. It’s an Offenhauser dual quad.

I just looked at the intake, it’s gotta be the inserts. There’s no pockets for them to sit in like the stock manifolds.

Yep. The intake stays lifted a bit. Take em out and put some Permatex #2 around the water ports and re install.

Yes, bought new gaskets already so that’ll be tomorrow night. I appreciate the help, would’ve made the same mistake again had I not posted.
Thank you!!!

Just also check that the intake gaskets and valley pan (and its gasket) have no interference..

Sam

I've always put a light coating of Right stuff on each side of the gaskets at the water crossover. I also put a small amount on the rubber donut at the bypass. I've never had any leaks.


I've also put a small flat washer on the valley pan bolt and a small amount of sealer under the washer. Prevents oil migration on top of valley pan.

Yes the valley pan is clear. I had notched this valley pan before I had put the Tripower on it that I used before.

You will typically get a leak if you tighten the fasteners in the wrong sequence.

1) Install all of the fasteners in the intake LOOSLY

2) Tighten the bolt that squeezes the "O-Ring" seal between the timing cover and the intake manifold FIRST.

3) Tighten the rear intake fasteners to the cylinder head.

4) Tighten the front intake fasteners to the head.

5) Tighten the middle intake fasteners to the head.

6) Now go back and go back and loosen one fastener at a time on the intake and then torque it to specification. The Water Cross-over will not leak and the intake will be installed properly.

Thanks Delbert Forrest, World War II Mechanic Instructor and Chief Pontiac Mechanic at my Uncle's Pontiac Dealership. RIP.

Tom V.

Will do! Thank you guys!!

Any problem with adding the counterbore to the intake manifold bolt holes on an aftermarket intake (RPM) so the plastic retainers will clear? I like how they hold the intake gaskets in place.

On factory heads only. The factory heads and intake have provisions for those retainers. So, if either the heads or intake are not factory, I don`t use the retainers.

One other comment.

The Factory Intake manifolds and heads were not cast up for perfect port alignment.

So a Pontiac Guy has a set of heads ported or at least Gasket Matched and makes some marks on the intake or drills pin alignment holes to get the intake on the heads in the exact spot for port alignment.

Then they try to bolt the intake on the engine with the timing cover and find that the "O-Ring" between the Timing Cover and the Intake no longer seals properly. So they cut the water cross-over so that they can still have the proper port alignment and the sealing on the "O-Ring" to the Timing Cover.

If you have a rare intake system on your Pontiac Engine, along with rare heads, just follow my suggestion in the previous post and seal the Timing Cover to the Intake properly. Rare RA-IV heads that have been messed with rapidly lose their value if ground on, especially a correct date original set of heads for the engine, be it Tri-Power, RA-II, RA-IV, or SD-455 Heads.

Tom V.

Thank you all for the input. Tom, I did as you said, it’s back on, no inserts.

Hope all is good for you now. Glad to help

Tom V.

Thank you again!