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Intake manifold leak causes rusting

D

diveryates

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"Can an intake manifold leak/c

"Can an intake manifold leak/crack cause rust to gradually eat away a cylinder head at the exhaust ports? In this case, rust flacking is starting to be evedent at a point where the two center exhaust ports are located on a '83 305. All other points along the head/exhaust manifold gasket junctions are fine starboard side. Portside's fine. Thank you"
 
"Further research allows me to

"Further research allows me to answer my own question:

The problem is not the intake manifold. It is a faulty exhaust valve. A worn exhaust valve can create the situation where, through defective sealing during the piston down stroke, suction is created and draws raw water in, then expelling it out the port on upward stroke of the piston. Over time, the captured moisture penetrates the head and manifold surfaces causing rust.
New head time."
 
"I'd be more suspicious of

"I'd be more suspicious of the exhaust manifold, riser or riser gasket than a valve."
 
"A very good observation! I wa

"A very good observation! I was able to eliminate this possibility. When the rust 1st showed up, I cleaned up the surfaces as best I could and replaced the Manifold, elbow and painted. Low and behold after some 50 hrs the rusting started to come back. I my view and as I suspected, this eliminated the Manifold/elbow as the source of the moisture."
 
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