I lost oil pressure on my '06 Silverado w/ 136000 miles. When I opened the hood to check the oil level, I saw the oil fill cap was missing. The engine had been serviced 7 days prior. The oil level was still at the full mark, the temp. was running normal. Is it possible that the missing cap contributed to the pump failure, or pressure loss? The oil looks clean except for some shavings, of course.
No.
“The oil looks clean, except for some shavings, of course”. That sounds like Marion Barry, the ex-mayor of Washington, DC, saying: “Aside from the murders, the crime rate in Washington is really quite low!”
Your oil (clean or dirty) is not supposed to have ANY shavings in it. Are those shavings on the dipstick? If your oil pressure is gone, I would surmise the oil pump broke, and the shavings ended up in the crankcase somehow. Another possibility is that the oil intake got plugged somehow, and the oil pump was unable to suck up any oil, and possibly destroyed itself. A third posibilityis that someone doing the oil change dropped something in the oil filler opening, which then got stuck in the valve gear and got ground up; hence the shavings.
Please let us know what service was done exactly, 7 days ago, and by whom.
I would not drive this vehicle another mile; have it repaired immediately, before you destroy the bearings and valve gear of the engine. Your garage has a lot to answer for; I would pressure them into fixing the engine, since your problems seem to have started with them doing the oil change.
How long (miles, months) was is before the engine was serviced previously?