I took the water pump off the engine and a 1/4 inch diameter water passage is almost rusted shut. Any way to remove the rust from inside the engine? Prestone make a flush for rusted engines but cant imagine how you would use it on a open cooling system.
Howdy, Well you would have to block all the openings and outlets in the block and fill it with the "flush" and let it sit long enough to dissolve the rust. It it's strong enough to dissolve the rust, it's strong enough to dissolve elemental iron.
The trick would be to stop the process before it "eats" through a thin spot and completely destroys your block..............(which IS really NOT possible because you cannot see inside to find the "thin spots"!)
NOPE. Time for another engine.
That rust is actually from the block (iron) . That means that you do not know how thin (cyl to water jacket wall thickness) the jackets & cyls etc are getting. Eventually they'll rust through someplace.
You can get yourself a wrecking yard engine though. Find a similar year 5.7L /350 cu-in out of a truck. replace the core plugs with brass, and get new manifolds and risers. Swap all the marine specific 'stuff" over, and you'll probably need a "new" intake manifold if the truck manifold won't work.
There is no practical way to clear a completely clogged engine.
Regards,
Rick
