Oil change with Mityvac question

[loneryder]

Most car/engine manuals say to run the engine to warm up the oil before draining it. If one is using a 0-40 oil, wouldn't it drain or vacuum out just as easily cold since it is @0 wgt? If you warm it up, doesn't it become a 40W by definition? I have done it both ways but I mostly use the vacuum extraction method these days.
Isn't it easier to vacuum out a 0W vs a 40W?

 

[RooflessVW]

Wut.

Oil is always thicker when it is colder.

 

[TTK]

I have and use an oil extractor on my Volvo and I can say that you will need to get the oil warm/hot in order for the extraction to be reasonable easy.

 

[Donald]

You want the crud in oil all mixed up so it drains with the oil. That's more important than how it flows.

 

[RedOakRanch]

0w and 40 grade are two different terms, they are not on the same scale.

 

[dave123]

WOW

 

[kschachn]

There are no 0 weight oils. The "0W" is not a weight, at least not at all like the 40 is. It refers to a cold weather performance specification that the oil has to meet. 0W is the best performance, followed by 5W and 10W and so forth. You may as well just substitute letter grades for the performance where 0W = A, 5W = B and down the line. The number before the W cannot be compared to the number after the dash. It doesn't work like that.

And as the oil warms up it doesn't "become" anything. 0W-40 is a 40 grade oil just as 5W-40 is and 10W-40 is too. They all are. The 0W-40 just thickens less at very cold temperatures.

 

[simple_gifts]

oil thins out as it gets hotter; that is all you need to know to make the right choice.

 

[spk2000]

Don't get it too hot as it will make the tubing too soft which then collapses

 

[Danh]

As other have said, hotter=thinner. If the theory doesn't grab you, I've tried extracting oil both hot and cold: cold takes about 10 times longer.

 

[loneryder]

Originally Posted By: RedOakRanch
0w and 40 grade are two different terms, they are not on the same scale.


My question was assuming both numbers referred to weight. Since the first number is not really a weight but a reference point, that answers my question. I know about not getting it too hot but I don't have "crud" in my oil pan. Some vehicles take a long time for the oil to drain back into the pan.

 

[loneryder]

The 0W-40 just thickens less at very cold temperatures. [/quote]

Thanks

 

[cheech279]

I used my LiquiVac extractor today for the second time. I let the car cool for 45 minutes after a 20 minute drive. I should have let the oil cool a lot longer. When I was done, I saw in the instructions the engine should be warmed up only for two minutes.