AOS?
Oil Catch Can Question
- Thread starter RockyRob
- Start date
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Alwaysthinkin
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JasonH
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Air Oil Separator.
I think you are slightly confused. An air oil separator is what we are calling a catch can. It separates oil from the hot EGR air, and captures it in the catch can. Are you talking about a breather? Which is a issue on our modern closed system.
JasonH
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The AOS does the same thing as the catch can, but also drains back to the oil pan. No dumping necessary.
By definition, not all air oil separators do that. None of the catch can setups out there for these platforms currently do that. Even UPR's VERY expensive setup doesn't.
Also, these catch cans ARE Air Oil Seperators. You are talking about a specific type of Air Oil separator that drains. Also, you would have to filter it even further to drain, because a lot of what is caught is moisture. Wouldn't want to intentionally add water to your oil.
JasonH
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Thanks for clarifying. I guess it's like a square being specific type of rectangle. When I first purchased the vehicle and read about the catch cans, I wondered why they didn't drain back to the oil pan. When I googled it, the search came back with the AOS. So I figured that was the difference between the two. I think the water draining back would evaporate at operating temperature? Especially since it wouldn't have an opportunity to accumulate if the vehicle is driven regularly.
I hate to admit it because I do most of my own maintenance and minor repairs, but I hate popping the hood on my Expedition. It's a rat's nest in there, and the vehicle is very tall. The thought of having to drain a catch can repeatedly is anathema to me.
Common misconceptions.
Water does not evaporate when mixed with oil quickly at all especially when in a closed system like a motor. With it being churned and pumped it stays in suspension, and dilutes the oil, and it can cause hotspots and generally decrease the good properties of the oil.
If allowed to sit, the water actually goes to the bottom, with oil on top. That prevents the water from being able to come in contact with the air and evaporate.
The Catch Can is a piece of cake. Unscrew, empty, screw back on.
I get all oil changes done at Ford Motor Co with synthetic blend. I will tale a picture soon. We don't drive it much since we use the car with netter mileage.
When I emptied it,, it looked like coffee with milk in it. Very watery.
When I emptied it,, it looked like coffee with milk in it. Very watery.
Perfect. You are welcome to post a picture, but it is due to the cold. Do you idle a fair amount? That will typically cause it to collect more moisture.
