Catch Can Oil Recirculation

[BaconBait]

So I'm pretty lazy and really don't want to empty out the catch can if I don't need to. So the question is: Is there any downsides to having the catch can recirculate the oil back into the oil system instead of into a reservoir?

[brockallentaylo]

None that I know of. I have always setup a return if it was convenient to do depending on the placement. Although I did not do it on my 1.8T, the resivoir sits by the battery and it doesn't have but maybe a teaspoon in it after 5K miles or so.

Just use an ice maker kit to tap into your turbo drain line for the return LOL!

[BaconBait]

Since I have a -10 AN line for my turbo oil return, I was thinking more like adding a pressure gauge fitting in the line and putting a hose fitting in where the gauge would normally go. Roughly $25 for the parts plus hose and clamps.

[brockallentaylo]

Dude, I was joking.

[1NaudiA4]

Have you seen the crap that comes out of your catch can?.... I really hope your not thinking about putting gasoline and water into your oil

[brockallentaylo]

Have you seen the crap that comes out of your catch can?.... I really hope your not thinking about putting gasoline and water into your oil

Ohh picky picky, there is a lot of debate on this and I really don't sway either way. I change my fluids enough I think it is a negligible amount of nastiness. Besides 99% of cars have been feeding that goo into the intake manifold for the last 50 years and even then you engine can last 250K+ miles if treated properly. Although if I had my rathers I would have the engine digest it (manifold) instead of have it remain in the oil, but I just don't care enough either way, my rotella comes out looking pretty much like it did when I put it in at 3K miles. Could be a bad idea if you are running an overly rich tune and I think a lot of people do.

[1NaudiA4]

Ohh picky picky, there is a lot of debate on this and I really don't sway either way. I change my fluids enough I think it is a negligible amount of nastiness. Besides 99% of cars have been feeding that goo into the intake manifold for the last 50 years and even then you engine can last 250K+ miles if treated properly. Although if I had my rathers I would have the engine digest it (manifold) instead of have it remain in the oil, but I just don't care enough either way, my rotella comes out looking pretty much like it did when I put it in at 3K miles. Could be a bad idea if you are running an overly rich tune and I think a lot of people do.

Its one thing to feed it into the intake manifold where it gets burned off but its entirely different when you cycle all that nasty shit back into your oil. The point of the OEM PCV system was to extract that nasty stuff out of the crankcase.... if you have a catch can that catches that nasty stuff and then just puts it BACK INTO the crank case then there is no point in even having a catch can.

[99blueb5]

just drain it, its really not that involved, on my catch can i have a guage type deal on the outside and it shows how full it is

[PoormansA4]

Have you seen the crap that comes out of your catch can?.... I really hope your not thinking about putting gasoline and water into your oil

I would have to agree with this guy, if you look at some UOA you will see how you don't want fuel dilution.

[BaconBait]

Its one thing to feed it into the intake manifold where it gets burned off but its entirely different when you cycle all that nasty shit back into your oil. The point of the OEM PCV system was to extract that nasty stuff out of the crankcase.... if you have a catch can that catches that nasty stuff and then just puts it BACK INTO the crank case then there is no point in even having a catch can.

All that nastiness is already in the oil. Maybe it's just me, but I was under the suspicion that the Positive Crankcase Ventilation system was meant to vent the pressure build up from blow-by and that the oil/gas mix that it happens to produce is simply caught in the system.

Dude, I was joking.

The "LOL" gave it away. I just wanted to share my thoughts.

[1NaudiA4]

All that nastiness is already in the oil. Maybe it's just me, but I was under the suspicion that the Positive Crankcase Ventilation system was meant to vent the pressure build up from blow-by and that the oil/gas mix that it happens to produce is simply caught in the system.

That nastiness is not already in the oil, some of it is but the majority of it is in gas form. As I was saying, the stock PCV system or a catch can system will extract or catch the gasoline and water in the crank case. Given it will not catch all of it but it will catch some of it... this is part of the reason why it it not a good idea to drive short distances very often where your engine vitals don't get up to temp. If everything does not get up to temp all that stuff will stay in liquid form in your oil instead of turning to a gas where it can be picked up by the PCV system or catch can.

If what your saying is true then there would be absolutely no point to a PCV system or catch can system.

Anyways heres how I drain my catch can...

Tapped my catch can for a 3/8" ball valve and then ran some 3/8" roll copper to the ground so when I want to drain it I just have to put a bottle underneath and turn the valve.

[brockallentaylo]

Its one thing to feed it into the intake manifold where it gets burned off but its entirely different when you cycle all that nasty shit back into your oil. The point of the OEM PCV system was to extract that nasty stuff out of the crankcase.... if you have a catch can that catches that nasty stuff and then just puts it BACK INTO the crank case then there is no point in even having a catch can.

I have to disagree on this, the gases and moisture still get pumped into the atmosphere or wherever your can is venting for the most part. Some oil gets splashed into the can by accident and then it's constant exposure to the gases and moisture that are boiling off and traveling through your can and out to the atmosphere cause what little oil is in the can to look like a mess. If the oil doesn't sit in there that does not happen.......to a degree.