I finally got my 79 F-350, 460, running smooth. However I noticed that when it warms up there is sound similar to an exhaust leak. I thought it might be the donuts on the exhaust manifold/tail pipe connection. However I found out that there are no donuts on this. Is there a chance I have a crack in my exhaust manifold? If so how can I actual locate it? A visual inspection can't find it. If anyone can help me out, I'd sure appreciate it.

 

Have something very similar on mine and it turned out to be the manifold being pitted on the right side where the exhaust attaches to the manifold. If so fill the pitting and then seal the pipe. Hope this helps.

 

To locate the leak try this:
Take a length of hose, fuel hose or heater hose works well, hold one end to your ear and move the other end around the suspected leak. When you find it, you'll know.

 

It could be the EGR spacer plate gasket leaking. These are bad about leaking between the intake manifold and the plate.

 

To find an exhaust leak and get rid of the mosquitos in the neighborhood connect a small vac hose to your engine and stick the other end of the hose in a container with a few ounces of ATF. let the engine suck a little of that at a time into the engine at a fast idle and anywhere you have an exhaust leak you will get white smoke. This is great to find the smallest leak or even cracks in manifolds. It is also a good top end cleaner and lube.

Beware! This has not been tested to be OK on O2 sensors and converters. Just in case somebody with one of those newfangled electronic uncontrolled vehicles tries to use this tip.

 

I was doing that exact thing to my 390, minding my own business, looking for a leak, and the Fire department showed up.

They gave me a lecture on Air quality.

Dont use so much ATF that it makes a House fire sized cloud.

 

Thanks All. I'm going to give these a try. I'll let you know what I found. This is a great site, and everyone is always helpful. It's gotta be a FORD thing.

 

I have a Secret!! Check the Choke !!!

My 78 460 has no EGR so no leak there.

The Dam choke is HEATED by Exhaust!!!

The little two bolt plate was leaking and giving me that tick!!!

I can tell U how to fix it if U want.

 

You can also try having a friend block up the exhuast outlet with shop rags while at high idle. You might be able to hear/feel it easier.