Sorry if this has been asked before. I could not find similar threads on searching.
When changing oil how important is it to drain all the old oil?
Generally when mechanics put the car on the lift they take out the plug and do something else for a while as it drains. The car is level and the oil has pretty much stopped dripping or an occasional drip by the time they get back to removing the oil drain can.
Since the oil is warm when flowing out I would think most of the dregs on the oil pan bottom would be flushed out.
There are recesses and pockets in the engine and I guess the only way to get it all would be to turn the engine a few times or tilt the car which would be impracticable.
When I do snowblower single piston engines quite a bit of old oil comes out when the engine is tilted back and forth so I thought it might be the same for a car. Just how much of a difference this makes I'm not sure but I do it anyway.
The other day I got my oil changed. The lift was occupied so they used a floor jack to lift the front end to get at the filter and pan bolt. The car was angled quite a bit and I thought it would leave several ounces of oil oil in the engine and pan so requested they level out the car. They put jack on the other side so the car was side to side leveled but still had an angle front to back. The front was about a foot higher than the back so I asked to drop the front to let all the oil drop.
I thought it was a reasonable request but the shop guy did not but did it anyway. So the question is how important is getting "all" or "most of" the old oil out? Certainly it won't make a difference that would be noticeable quickly say 50,000 to 75,000 miles. How much of a difference would it make over the life of a car in 200,000 miles? My car has 269,000 on it currently and I'd like to see it do 300,000.
When changing oil how important is it to drain all the old oil?
Generally when mechanics put the car on the lift they take out the plug and do something else for a while as it drains. The car is level and the oil has pretty much stopped dripping or an occasional drip by the time they get back to removing the oil drain can.
Since the oil is warm when flowing out I would think most of the dregs on the oil pan bottom would be flushed out.
There are recesses and pockets in the engine and I guess the only way to get it all would be to turn the engine a few times or tilt the car which would be impracticable.
When I do snowblower single piston engines quite a bit of old oil comes out when the engine is tilted back and forth so I thought it might be the same for a car. Just how much of a difference this makes I'm not sure but I do it anyway.
The other day I got my oil changed. The lift was occupied so they used a floor jack to lift the front end to get at the filter and pan bolt. The car was angled quite a bit and I thought it would leave several ounces of oil oil in the engine and pan so requested they level out the car. They put jack on the other side so the car was side to side leveled but still had an angle front to back. The front was about a foot higher than the back so I asked to drop the front to let all the oil drop.
I thought it was a reasonable request but the shop guy did not but did it anyway. So the question is how important is getting "all" or "most of" the old oil out? Certainly it won't make a difference that would be noticeable quickly say 50,000 to 75,000 miles. How much of a difference would it make over the life of a car in 200,000 miles? My car has 269,000 on it currently and I'd like to see it do 300,000.