Oil Catch Can Experience

[thecowdoctor]

I purchased a 2020 SX with 60000kms in 2021. Car performed well. At 125500 kms (75000 miles) I installed a J & L oil catch can. (nice product, easy install). When we checked it a few weeks later the catch can (3oz) was FULL. We started to check it every week and it always had a milky product.. about an ounce. Traded the telly last week at 129000 kms for a new 2024SX..when we removed the catch can for the sale, it again contained the milky product. I would say in the 3500 km (2100 miles) the catch can collected over 150 mls (5 ounces of liquid. On letting it sit in a jar it separates into a cloudy, milky portion on the surface (10%) and a clear yellow liquid (90%) that looks and smells like gasoline. The last time we dumped it, there was some frozen stuff (water?) in there too.
Does anyone else have experience with their catch can? I am wondering if the clear liquid is in fact the fuel that the Atchinson engine pushes past the inlet valves. Running on 5W30 synthetic oil.
Currently I have not installed the catch can in the new 2024 SX.
Thanks for your input.

 

[G-442648]

Thank you for sharing these results with everyone. I will say these catch can byproducts are a welcome surprise, as it appears to be primarily a fuel and water mixture, which is easily and safely combustible without much concern for carbon buildup on the backside of the intake valves. Now if the can was full of mostly liquid oil, then I'd be much more concerned with the factory PCV system being inadequate for preventing this common DI engine issue.

 

[thecowdoctor]

Thank you for sharing these results with everyone. I will say these catch can byproducts are a welcome surprise, as it appears to be primarily a fuel and water mixture, which is easily and safely combustible without much concern for carbon buildup on the backside of the intake valves. Now if the can was full of mostly liquid oil, then I'd be much more concerned with the factory PCV system being inadequate for preventing this common DI engine issue.

Since the weather has warmed up, the contents of the catchcan have reduced considerably. Think it was the condensation in the winter causing most of the liquid.

 

[thecowdoctor]

I did install in the 2024 and results were similar to the 2020 until recently when the weather warmed up.

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[drizzt]

I did install in the 2024 and results were similar to the 2020 until recently when the weather warmed up.

Yes, the liquid you see is mostly from condensation due to living in colder clilmates. I got 2.5oz of latte like fluid that smell much like gasoline after driving little over 1k miles. You can buy J&L extension that doubles the capacity. So yes, even with the extension, I would check the can more often during winter time.

Oil Catch Can Experience

Installation itself is very simple, so reversing the process would not be difficult at all. I was cursing up and down when trying to remove the PCV line, including a run to Harbor Freights. But that will be your only difficulty. Your perseverance will pay off. thanks...i didn't look too...

tellurideforum.org

 

[MrMCar]

Since on/about 1995 onwards (brand/engine/emissions family dependent) all engines are now "sealed". Some are even bereft of dipsticks to further remove a leak point. In the past all the engine vapors were allowed to escape out to the atmosphere. Now they're all captured, most usually off of the valve cover or nearby, pulled down a hose utilizing some vacuum and usually sent into a separator.

From there the slurry is allowed to sit collect and separate. The liquid (mostly oil) is returned to the crankcase (oil pan) and the vapors are sent back into the intake stream. They are burned via combustion and processed by the catalytic converter. Therefore making it "green" rather than vented out to the atmosphere.

There are many caveats to the above. Most if not all manufacturers struggle with design and implementation of the CCV (closed crankcase ventilation) system. Most work well, given one huge caveat. The engine oil must reach and stay at full operating temperature for at least 15 or so minutes.

The oil and engine are cold in the morning, yes even in summer because full operating temperature is somewhere in the 100°C (212°F) range. As the engine/coolant/engine oil warm, condensation will form. Now that we're sealed up the vapors cannot escape out, like that of a teapot. Tantamount to your favorite Sunday pasta sauce simmering on the stove with a tight lid on it. All of that vapor has to go somewhere. It goes into the CCV system. Most of these systems work if you get the oil fully hot. Which by the way takes 3 or 4 times longer than the coolant. When the oil reaches 100°C the water vapor boils off and is sent through the intake to be burned in the combustion chamber. The milky residue ("milkshake" in the BMW community) collects on the insides of the CCV hoses, underside of the valve cover(s) and the oil filler cap. Some remove the oil filler cap and start to wonder about a blown head gasket...

The design flaw:
In North America, a large percentage of the population does NOT drive for at least 20 minutes each trip. This never allows the engine oil to reach full operating temperature and boil off the water vapor. Just even the smallest amount will turn the oil milky white. (what you see in the catch can) This accumulates and can even clog in the most extreme cases some breather hoses. BMW had such a problem with some engines near/towards the north, they even retrofitted heaters to the hoses/system.
My wife used to take the train to work. A scant 5 blocks from the house. Here I was, each and every morning starting and warming up the car for about 15 minutes before she departed so not only was I doing myself, but the engine a favor.

If you drive longer distances as an average and/or liver in warmer climates, this is less of an issue. The delta between cold start and fully warm is much less; less condensation. And/or full burn-off.
This gives rise to the popularity of catch cans. Ones of VERY good design & engineering work well if your car is affected by the above.
A nice long spirited drive of an hour will most often burn off the offending gunk.

Sometimes it can get really bad. I hate the moniker, but it best describes what happens. Soccer mom (sorry again) gets into car and goes to starbucks. Then to drop off then home. Repeats with trips to the store. All short and the coolant (let alone the engine oil) never warms up. This puppy needs more driving or possibly a catch can.

Yes if you're affected, the colder it is out, the more often you will need to empty. Keep in mind that home-made and/or cheap systems will create a vacuum leak. Any vacuum leak will eventually turn a "check engine" light. So if you are in the market for such a system, buy quality and take your time to install it well.
HTH?

YMMV