Engine knocking noise after oil drained out do to drain plug falling out

  • 2.1L
  • 120,000 MILES
My vehicle is a Daeqoo Evanda. Recently, I was driving my vehicle and the oil plug somehow fell out of my oil pan causing my oil to drain out. The oil pressure light came on and the car turned off causing me to pullover. I replaced the oil plug and added a new oil filter and new oil. Ever since then my car has been making a knocking noise and the noise increases as the gas is pressed down. The oil pressure light is on when the car is stopped the light disappears. I was told by an auto shop to use 5W30 oil. What issue does it sound like I’m dealing with and would I need a thicker oil?
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Thursday, January 23rd, 2020 AT 1:56 PM

1 Reply

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The damage has been done to the bearings already. They have a clearance, or gap, between moving parts in the order of .005", give or take a couple of thousandths. That's the thickness of three sheets of paper. Within just a few seconds with no oil pressure, those bearing surfaces will begin to be chewed away. The increased clearance leads to the hammering sound heard as knocking. The bearings are highly-polished smooth metal strips made up of three layers of metal. The first layer is very soft so dirt particles can become embedded in them rather that scratching the highly-polished crankshaft "journals" those bearing ride on. Once that soft outer layer starts to become chewed up, that damage progresses and the knocking gets worse very quickly.

That increased clearance lets the pressurized oil seep out much too quickly. That reduces the flow of oil to all the other critical places, so more damage occurs. The repair is to rebuild the engine with mostly new internal parts. Given the age of the car, a more common solution is to replace the engine with a good used one from a salvage yard.

For related information, take a look at this article:


A typical engine bearing is shown in step 6.
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Thursday, January 23rd, 2020 AT 3:21 PM

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