[tony17112acst]

My Rainier's 5.3 L (with 180k miles) started to make a loud rattling noise from the engine area and it is in sync with the engine RPM's, not the wheels turning.

I checked the oil level and it was within the hash marks on the oil dipstick, so we made an appointment to have it diagnosed at the dealer.

I'm no expert, but I swear the noise sounded like it was low on oil, so even though the oil was NOT low, I OVERFILLED it with about 3/4 of a quart ...and the noise quieted 85%! I can hardly hear it now, but it IS still there. So I canceled the dealer diagnosis so I could do some research, but my searches aren't finding my circumstances.

So what could this be? Any input is appreciated! Thanks!
-Tony

 

[Ravalli Surfer]

From this end of the internet it seems as though you are splash lubricating the bearing(s) with the crankcase being overfilled.

Engines won't live long with this being the only oil the bearings get.... unless you've got an old (a very old) Chevy Blue Flame 6.

They were "dippers"or "target" engines that either threw oil up in the general direction of the bearing journals, or scooped oil from troughs in the pan into (first) the rods then to the mains.

Target engines actually had a rail of squirters that SHOT oil "at" small slots or tapered cups to capture a bit of oil at the big end of the rod as it came by.

3/4 of a quart overfill isn't very much, but it might be sufficient to get oil splashing by the journals whipping the oil into a frenzy.

 

[tony17112acst]

Yeah, it's not much. It's a 2004 Rainier.
I may just make another appointment with the dealer and pay to have it diagnosed. I just don't trust them: since this is an engine with 180,000 miles on it, they can say almost anything is going bad on it.

 

[STSCowboy]

So what turned out to be the issue?