Join Date: Dec 2006
Location: Santa Clara, CA
What happens to microscopic particles? Well, basically, if they're smaller than the oil filter will capture and in the oil, they act more like tiny ball bearings than like sandpaper, they're too small to get caught in gaps in the engine and be dragged along and score or wear things. When talking about wear metals from aluminum bores it's even more silly to think about where the metal goes -- from the viewpoint of bearings and rings in steel bores and steel camshafts and such, aluminum has basically the hardness of soap, all that happens is that it serves as a lubricant helping keep the steel bits apart. Same principle as using walnut beads to clean heads, i.e., the walnut beads are so much softer than steel that they can't cause any damage to the actual head, they'll just remove any oxidation, carbon buildups, etc.
I've run magnetic oil plugs in a number of my vehicles to hopefully catch broken doohickeys before they get a chance to do much damage. In every single one of them the magnetic oil plug ended up with an oil-metal sludge on it (wipe it off with a shop rag, and it's *shiny*). One of those engines was a Chevrolet LS, a design notable for its durability and long interval between rebuilds. I don't run magnetic oil plugs anymore because they were more damaging to my mental health than the microscopic particles were to the engines and I never caught anything big enough to cause damage with them.
Lots of freakouts going on here making it hard for those who do have real problems to get help. The suggestion about a leakdown test by an independent mechanic if you're worried about your engine being "tappy" is a good one. As for me, I did listen closely to my engine and yes, it *does* make a "tappy" noise at idle, on *both* sides (but on the passenger side all the plastic from the airbox and battery box muffles it a bit). But I can't hear it with the hood closed. Personally, I'm not going to worry about it. This is a hot cam (steep slopes to hold valves open as long as possible before dropping them off) with strong valve springs and every valve train with a hot cam is noisy (the point of the VVT is to eliminate the down-low lump-a-lump and torque hole of a classic hot cam engine). As long as I can't hear it with the hood closed it's normal, because that's the design parameters that noise/vibration engineers use when designing the sound deadening -- if it wasn't normal, they wouldn't have added sufficient sound deadening to eliminate hearing it outside the engine compartment, because sound deadening is heavy and expensive and using as little as possible is the goal. Modern aluminum engines make all sorts of grinding tapping whirring noises that the old iron engines damped out -- you should have heard some of the motorcycles I owned over the years, you woulda thought their engines were disintegrating in place! But that's just how they sounded, right off the showroom floor. Which is one reason why I buy new vehicles if I can afford them -- so I can tell when a *different* noise happens, because it's only the *different* noises (the ones that don't exist on a brand new vehicle) that are worth worrying about. So far so good, not a single one of my vehicles has disintegrated due to a noise it had when brand new off the showroom floor...
Dog: Man's best friend. Cat: Man's weird reclusive roommate who poops in a box.