Draining Engine Oil vs Extracting Engine Oil
A few weeks ago I posted a picture of the oil extractor that I bought. I mainly bought it because someone at Volkswagen thought it would be a good idea to use a PLASTIC oil pan on the new MK7 GTI. It’s too early to know if a plastic oil pan is a good idea or not, but let’s shelf that for now.
When I posted the picture, it brought up a good point. Is extracting oil better, worse, or the same as draining it from the drain plug.
Before we talk about the Pros and Cons of these methods. Let’s be sure to define each.
- Draining Engine Oil
This is the process where a plug is removed that the oil drains out the bottom.
- Extracting Engine Oil
This is where a device is used to suck the oil out. For this discussion, let’s assume we are pulling oil out through the dip stick funnel.
When most folks think of an oil change, they think of draining the oil. Up until a few months ago, that is how I did every service. Let’s talk about the pros and cons of DRAINING oil first
- It is fast.
We are letting gravity do the work for us. On a hot engine you will get most of the engine oil out in about 5 minutes.
- You MAY get more oil out.
I say you MAY because that is not a guarantee you will get more oil out
- You can do other things while the oil drains.
I usually pull wheel caps off while I drain the engine oil
- It is a more traditional way to change oil
- It can be messy
You basically need to be sure you hit the target of the drain pan
- You have to raise the car up.
You need to have the car high enough to access the drain plug
- Risk oil pan damage
May oil pans are made of soft metal, or plastic, each time a drain plug is removed, the potential for damage is there.
Let’s look a little deeper into the Pros and Cons of extracting engine oil
All of the oil is pulled in to a container. Mine has a spout to make pouring easier
- No need to raise the car
This is great when putting the car in the air is not easy.
- No worry about drain plug damage
A you can see I am concerned about the long term on these plastic pans.
Mine is fairly loud
- Need air supply
With most of these extractors, you need a good supply of compressed air, or you have to manually pump the oil
- You may not get all the oil out
I have found that mine does not get all the oil out of some engines.
- It may take more time
On a cold engine, my extractor takes forever to pull oil out.
There are a few other points that I want to bring up about using an extractor. They may or may not be cons. It is more like just thoughts. Just because you don’t need to put the car in the air to drain the oil, doesn’t mean you don’t put the car in the air. You may still need to access the filter from the bottom. It is also important to put the car up in the air to do an inspection.
There is also the idea that debris in the engine oil will settle to the bottom. When a drain plug is removed, that will be the first to come out. This sounds like a good theory. But the oil filter will hold most of the debris. The oil is changed HOT. This means the debris doesn’t really have time to settle. Plus no matter what you do , there is still oil left in the engine. Heck there is still oil left in the pan.
Conclusion, which is better?
Well, like most good questions, the answer is “it depends”. For me, extracting the oil on a TDI that comes in to wait is perfect. The filter is on the top, the extractor gets all the way down to the bottom, and the oil is hot.
I can tell you that on a 2.0 FSI, there is is no point to use an extractor. I still have to put the car in the air to access the oil filter. It would be a waste of time to extract the oil, then lift the car to replace the filter.
What do you think? Is draining better? Do you get more oil out? Does a 1/2 of a cup left in the engine really matter? Post your thoughts in the comments below.