Intake Manifold Oil Leak?
 

It is that time of the year again up north and when I started the boat everything went perfectly, however, I did notice a small pool of oil on the port side of the intake manifold of my 7.4L 454 BBC. It appears when the engine is running the oil is slightly pulsing out of the gasket between the head and intake manifold where the crossover port (directly in the center of the carb). There are no leaks anywhere else. I have had a few guys tell me to pull those two bolts only and use RTV and then tighten them back down, however, I am unsure of the best solution. Can anyone explain what is happening (why oil in intake manifold) and how to correct the problem (can bolts be pulled or should the whole intake be resealed.

Thanks everyone.

Jed

after all those heat cycles the bolts can loosen up.remove the bolts one at a time and apply thread sealer on them.

This is good information. Is it best to start with only the one port which is leaking to see if this fixes it and leave everything else alone as it seems to be dry as a bone? I am also being given conflictiong information on the torque of these bolts from multiple sources. Any recomendations there?

You can actualy see the oil coming out on top of the intake? I would think if oil is coming past the intake gasket from the lifter valley you would have more problems than that.

Are you sure the oil did not come from the hoses from the valve cover that go to the flame arrester. Sometimes those will leak down the side of the flame arrester onto the manifold.
If you had a leak on the intake manifold I would expect to see it come out from the front or rear of the manifold.

I think 25-30 ft lbs if all the component's are cast, like stated above retorque the complete manifold, cris cross pattern, start in the middle to outside.

I think torque specs on those 3/8"-16 bolts is about 35 ft/lbs. Oil can easily weep up the threads of the bolts themselves. I would pull each bolt and clean the threads real good with some brake cleaner and a wire brush, then reinstall them with some Right Stuff of RTV Ultra Black on them and torque them back to specs. This might fix your leak if the gasket hasn't started to let go.

Are you seeing a lot of block pressure from blow-by? This shows up with a lot of oil coming out the breather tubes and sometimes the dipstick tube if severe.

What I can see is when the boat is idling there is a small part between the gasket and the intake manifold where there is some oil and it will pulse lightly in and out. I sprayed some soapy water on it and you will see a small line of fine bubbles/foam form only in that one section. There is no oil from anywhere else. After a day a running the boat there will be a very small pool of oil in the valley of the intake manifold. It does not come from the bolts directly as the motor is painted and the bolts are painted, however, the gasket is free of paint as it has flaked off there over time. There is no blue smole from the exhaust, just a white steam at initial start up.

1BIGJIM you mentioned bigger problem. What would those be?

Thanks again everyone.

Grab your cell phone and snap a picture of the problem, then post it here. That would help us to help you.

:worthless_without_p

Sounds like it may be exhaust from the exhaust crossover in the heads.

I had same issue cleaned and sealed the bolt and torqued it back down

Anny sugestions on a product to use for the threads?