Rust from exh. manifold sucked back into engine?

[oilyriser]

I just found what looks like tiny flakes of rust at the bottom of a used oil filter. There were some fine particles settled at the bottom of the Supertech 3593 oil filter can, so I wiped them up on my finger, then tried to pick them up with a nickel plated rare earth magnet. Most of the particles were not attracted, but after I cleaned off the magnet with solvent, there was something stuck there. I got out my 10x magnifier, afraid I was going to see shiny slices of metal that were cut loose by my 5w20 experiment, but to my surprise it looked like tiny flakes of rust. The pliers I used to peel open the filter were not rusty, nor was the hacksaw I used to start the cut.

Is it possible for rust flakes from inside the exhaust manifold to get sucked back into the engine, the same way as catalyst bits can get sucked back in those few Nissan engines that had that problem? If so, then this is another source of iron that could show up in a used oil analysis.

 

[bdcardinal]

possible. i know with newer mustangs with a certain brand of long tube headers there have been reports of exhaust valve damage. apparently the welds arent cleaned out properly and when they break off they get sucked back into the motor.

 

[oilyriser]

This might explain some of the mysterious black stuff that collects on my drain plug magnet. It also might explain why most engines always have Fe in their used oil analysis, while a few rare ones have zero. Maybe those have SS headers.

 

[JohnBrowning]

If your engine use's cam phaseing in place of an EGR valve then yes it can happen!

 

[oilyriser]

it does! there is no EGR valve on this engine.

 

[Quest]

LOL!

Come to think of it: if your engine has big enough crevice to pass along some exhaust manifold rust particles/EGR, it's done for!

black Fe power captured by magnetic drain plugs or expressed in UOA readings mainly comes from piston to cylinder wall wear (cylinder wall are pretty much iron sleeves or a cylinder bore out of an iron block).

 

[oilyriser]

The largest flake was maybe 0.02" wide and maybe .005" thick, so it could have passed through the ring gap and made it down into the oil pan. I'm glad that stuff settles to the bottom of the oil filter can, so when it bypasses on startup in winter, the particles don't get circulated to the bearings. Maybe I should stick a magnet to the end of the oil filter to make sure at least the magnetic bits stay put.

Yes, most of the black powder is probably metallic iron, but next time I'm gonna collect some of the buildup and check it out under the microscope.