Oil catch cans freaking work

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Antonm

Antonm

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GM is late to party on a factory oil separator for their V8s. As discussed earlier in this thread Mercedes had oil separators in the early 80's for sure (possibly earlier IDK), which that is now 40 years ago (dang I feel old all the sudden).

Most of the modern DI four bangers, especially the turbocharged ones, all seem to have some sort of elaborate, and expensive to replace, crankcase vent system that incorporates an oil separator.

Ford actually added back in port fuel injection on some of their engines, so those engines have both DI and port injection, for the purpose of keeping the back of the intake valves clean.
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Darkstar72

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"Ford actually added back in port fuel injection on some of their engines, so those engines have both DI and port injection, for the purpose of keeping the back of the intake valves clean."

Toyota does the same thing on some of their engines as well. I'm not completely versed in all things Toyota but I know that I have have heard they do they add port injectors as well on their DI engines to keep the back of the valve clean.
 

iamlegion

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Thought I would just throw my results in. EE catch can, about 55k miles, oil is Mobile 1 0w20 Extended Performance (for now).

I put about 2,500 miles on my truck and got just barely enough oil to cover the bottom of the catch can.
 

Silverado4x4

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Thought I would just throw my results in. EE catch can, about 55k miles, oil is Mobile 1 0w20 Extended Performance (for now).

I put about 2,500 miles on my truck and got just barely enough oil to cover the bottom of the catch can.
Yup not really worth the cost. Alot of people think they work great but don't realize these cans sweat water inside due to the cold metal and hot oil and vice versa , they dump the can and the oil is milky looking which means water from condensation inside the can.
 

jfoj

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JL Catch Can on my 2024 Yukon 6.2l. Currently around 5800 miles. Have checked and empied around 2500 mile each time with about 1/2"-3/4" in the can. Usually some water/mayo in the bottom of the can.

Caveat, 80% of my driving is highway. Very little town driving. Also if I start the engine, rarely does the engine run for less than 30 minutes.

If you are taking shorter 10-15 minute trips and you will have a hard time warming the oil up to even the coolant temperature. I have seen 226F temps on the highway so far with only 60F ambient temps. Will not have more data until later in the Summer when the ambients are in thr 80-90's+.

Would not run/own a DI engine without a catch can. BMW has has them standard for 25+ years, while there can be issues with them on BMW's, at least they have something.
 

iamlegion

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Yup not really worth the cost. Alot of people think they work great but don't realize these cans sweat water inside due to the cold metal and hot oil and vice versa , they dump the can and the oil is milky looking which means water from condensation inside the can.
It for sure condensates significantly more when it is cold out and it seems if you do short drives in the cold it is even worse and won heat up enough for that to evaporate. I don’t drive enough in the cold to worry.

It does seem they can be a bit unnecessary for some and it may be hard to really derive the value they provide. I don’t mind mine and it’s reassuring my truck doesn’t seem to accumulate much at all.
 
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Antonm

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GDI (gasoline direct injection) engine have a unique set of conditions compared to port fuel injected engines that makes the oil catch can helpful.

In a GDI engine no fuel ever goes across the intake calve, just air. But,,, that air has oil vapor from the crankcase ventilation (CCV) system, and exhaust gasses from the EGR system in it as well.

Throw that CCV system oil mist on the back of some hot intake valves, and combine it with the EGR gages, and you get an intake tract that absolutely will (not might, not maybe, absolutely will) fill up with a tar like carbon mess.

On port fuel injected engines there is fuel always spraying at the back of the intake valve, and the happy side effect is the fuel spray keeps this crap from building up to bad.

This new-ish/ unique to GDI engines condition has even sparked new snake oil chemicals to remove the buildup and some intake cleaning services (where they literally blast crushed walnut shells into the intake tract to in effect sand blast this buildup back off).

Since we can't (or shouldn't) do anything about the CCV system returning air (with oil mist in it) to the intake, or the EGR system returning exhaust gasses to the intake, then that leaves us with trying to remove the oil mist from the CCV air with an oil catch can to help prolong the time before we have to clean the intake tract out.

Here is an example of what a GDI engines intake tract looks like after about 100K miles.

GDI engne junk.png
 
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