I went to a Ford Dealership today to get my oil changed in my Corvette. I know, it sounds like an introduction to a joke, but my last vehicle was a Ford and my other vehicle is a Ford, and I really like the way this Ford mechanic works.

Anyway, I brought my oil and oil filter with me. I told the mechanic it would probably not take a full six quarts because when I had my first oil change done at the GM Dealership, they put six quarts in and it was about 1/2 quart over. The mechanic said okay and that he would put 5 1/2 quarts in and check the level.

SO, he drained the used oil, removed the old filter, put on the new filter and added 5 1/2 quarts of the new oil after replacing the drain plug. When he checked the level, it was a 1/2 quart low. He added the rest of the oil (a full six quarts) and it was right at the upper limit line - perfect.

I looked at him with a puzzled look on my face and he said it was probably the way the GM mechanic changed the oil. My Ford mechanic told me that he drains the oil and removes the filter before he puts the drain plug back in. If I understood him correctly, he said if you put the drain plug back in before removing the old filter, a small amount of old oil will remain in the system and not drain properly. He believes this is why I was about 1/2 quart of oil over with my last oil change.

I thought this was interesting and was wondering what others think about his procedure???

Thanks

 

I've never done it any other way. I always remove the plug, then the filter, and let it drain completely with both removed. I then put in the plug, and install the filter already mostly filled with oil.

 

Yea... It's been a long time since I changed my own oil, so I don't remember when I use to put the drain plug back in. Honestly, I could see myself draining the oil and putting the drain plug back in, before removing the old filter, just so I would not forget to put the drain plug back in and spill fresh oil all over the ground.

I guess this is why I have someone else change my oil...

 

Your Ford mechanic is correct...open ALL the holes to facilitate draining. The seal around the filter (as well as the gasket around the drain plug) may create a "mini vacuum" within the crankcase and let a small amount of the old oil remain (if opened separately).

 

I would hope that everyone follows this procedure....it is very basic.

 

By removing pan plug, filter, and fill cap, you are venting the system. Allowing the oil to drain completely out of the car.

 

Same here. ALSO, while draining you should also remove the fill cap to allow it drain (breath) more freely.

 

I just changed my oil about a week ago. I take out the plug, remove the filter, and then go do something else for a little while and let it completely drain.

 

I remove the two drain plugs(I have a 09 Z06) and then go do something else for a half hour as that allows the oil filter(and the oil in it) to cool some. I then remove the filter and then go find something to do for another half hour. Then I prefill the new filter, oil the gasket, and install, then replace the drain plugs. Lower the car, fill with 10.5 qts of oil and then start the car and check for leaks. My time is worthless(for the most part), so allowing an hour to drain the oil is no biggie. I just find something to do in the garage(that I should have done months ago) while the oil is draining.

 

That's the same procedure I've used for years. Plus I remove the fill cap.

 

I don't believe the sequence on removing the filter and drain plug has any effect on how much oil comes out.

Likely a 1/2 quart was just due to not letting it fully drain out in a hurry.

I did mine Saturday and did notice there is a lot of oil in an LS2 in the block above the filter. I have never noticed any engine overflow the filter so much after loosening the filter to remove it. It's not likely having the drain plug back in the pan would prevent this from draining with the filter off.

Sounds like an old mechanics tale.
LJ

 

Do all my cars, truck, ATVs, M/C and boats that way.

 

Sounds like your mechanic knows what he's doing.

But check your rocker panels... maybe he doesn't know how easily they are damaged.

 

That usually includes checking other parts of the car or cleaning the garage a bit. Never fails to make two or more chores out of one.

 

Incorrect .

 

It is what I do as well.

 

That too!!

 

As soon as the majority of oil drains through the drain hole and it is just dripping, the engine is self venting through the oil drain hole as there is no check valve in the oil drain hole. Really no need to remove the oil fill cap ahead of the drain, but doesn't hurt anything if you do.

 

I'm using the UPF-44 Premium Oil filter and on the filter it says to fill up filter with oil before installing it.