To all those who think catch cans are a waste of time and money: stop in for a look!

[SubieRubyRoo]

2019 F150 3.5 EB. Dark sample on the right was 2400 miles (road trip) in October, no freezing temps, ran E30 the entire distance.

The milky goop on the left was from 3000 additional miles (no OCI) since about October 28th. This sample only had E30 for one tankful. There was only 2 hours total idle time during the time the milky sample was collected, so it wasn’t low temps or short trips that led to all the extra condensate.

Even though the oil on the right isn’t snotty and contaminated, I’m still glad it didn’t make it into my intake. Upon seeing the milky stuff, I decided to keep the samples separate because I’m having both analyzed. Should be some interesting results!! JLT catch can on passenger PCV line only.

 

[Rand]

is the catch can metal?
Lower temps obv. condense much more moisture into the liquid.

 

[SubieRubyRoo]

is the catch can metal?
Lower temps obv. condense much more moisture into the liquid.

Yes, aluminum. But even in 10* weather the can itself is so hot you can’t hold the can, so I doubt that’s a major factor.

 

[Owen Lucas]

Ok, noob question, but why do you need a catch can? Is this for cleaner crankcase ventilation?

 

[Rand]

Yes, aluminum. But even in 10* weather the can itself is so hot you can’t hold the can, so I doubt that’s a major factor.

well if it was hot enough it would boil off the moisture.. and that doesnt seem to be happening.
OTOH goo like that is common under oil filler caps this time of year.. the ole Mayo deposit.

 

[SubieRubyRoo]

Ok, noob question, but why do you need a catch can? Is this for cleaner crankcase ventilation?

I have a GDI (hybrid) engine and it’s suspected that oil in the intake via the PCV contributes to intake valve deposits. ~4oz of oil and slime didn’t make it into the intake of my truck. That makes me happy.

 

[jetman]

I've had a catch can on my 07 Yukon w/6.2L for 4+ yrs and 45k miles. I get about 1 oz the dark stuff every 5k miles. Engine has 185k miles.

 

[carviewsonic]

I have one on the Impala, I think it's worthwhile to have a catch-can on GDI vehicles. I would rather empty the catch can at each OCI, than have that stuff coat the intake and bake onto the intake valves. Collects about 1.5 ounces per OCI in the summer, and maybe twice that in the winter.

 

[SubieRubyRoo]

Dropped the samples off at the lab today. Should hear something back tomorrow.

 

[RhondaHonda]

Does yours use any oil? My 2019 and my current 2021 don’t seem to use a drop of oil between changes (5,000 mi). I am intrigued but just never got around to buying a catch can.

 

[SubieRubyRoo]

Does yours use any oil? My 2019 and my current 2021 don’t seem to use a drop of oil between changes (5,000 mi). I am intrigued but just never got around to buying a catch can.

Nope, the level stays right where I put it at the fill time. The milky snot makes sense; the lab was curious that I got an ounce of what appears to be straight oil in 2400 miles, and there’s only a tiny, tiny bit of actual oil in the “winter” sample. Not sure if this was the HPL PCMO liberating stuff left behind by Ravenol, MC, and Pennzoil, but if the oil accumulation stays gone when the weather warms…. I’m not sure what else I can attribute it to other than previous oils.

In addition, I picked up my 6 quarts of No VII Euro 5w30, 5 quarts of Differential Life 75w110, and 2 gallons of the PAO Green CC ATF for springtime maintenance today. Quite pumped about it.

 

[BMWTurboDzl]

2019 F150 3.5 EB. Dark sample on the right was 2400 miles (road trip) in October, no freezing temps, ran E30 the entire distance.

The milky goop on the left was from 3000 additional miles (no OCI) since about October 28th. This sample only had E30 for one tankful. There was only 2 hours total idle time during the time the milky sample was collected, so it wasn’t low temps or short trips that led to all the extra condensate.

Even though the oil on the right isn’t snotty and contaminated, I’m still glad it didn’t make it into my intake. Upon seeing the milky stuff, I decided to keep the samples separate because I’m having both analyzed. Should be some interesting results!! JLT catch can on passenger PCV line only.

Compare that volume of condensate to the amount of fuel burned. It's really nothing I'm the grand scheme of things.

 

[Tomioka]

Ok, noob question, but why do you need a catch can? Is this for cleaner crankcase ventilation?

In turbodiesel applications (EPA 07+) it's to keep the charge air cooler and plumbing free of oil mist. In those applications a replaceable crankcase breather filter is used where it contains a felt absorbing material as well a way to drain back into the crankcase. Cummins recommends changing the Crankcase Ventilation Filter every 75,000mi/60mos.

 

[2strokeNorthstar]

Compare that volume of condensate to the amount of fuel burned. It's really nothing I'm the grand scheme of things.

That's my thinking. It's like a drop of oil into a jet intake. Imagine the amount of air/cfm that that small amount of oil could have been diluted into in 5k miles.

 

[SubieRubyRoo]

Compare that volume of condensate to the amount of fuel burned. It's really nothing I'm the grand scheme of things.

There’s only a 600-mile difference between the two samples. Oil only @ 2400 miles; 3oz of nearly all water & emulsion after an additional 3000 miles. You think these results are insignificant?

 

[BMWTurboDzl]

There’s only a 600-mile difference between the two samples. Oil only @ 2400 miles; 3oz of nearly all water & emulsion after an additional 3000 miles. You think these results are insignificant?

Ya I do. I mean water accounts for approx 13% of the combustion byproducts from burning gasoline. In any case instead of the water vapor going out the tailpipe it's condensing in the cooler catch can.

 

[KrisZ]

The thing with catch cans is that the liquid you see in it, is not what goes through the engine. All of that is suspended as tiny droplets, it’s harmless. The catch can condenses all of that into liquid and all of the sudden, it looks like scary stuff, especially when water mixes with oil.

 

[BMWTurboDzl]

The thing with catch cans is that the liquid you see in it, is not what goes through the engine. All of that is suspended as tiny droplets, it’s harmless. The catch can condenses all of that into liquid and all of the sudden, it looks like scary stuff, especially when water mixes with oil.

They're big sellers in BMW circles because individuals are scared to death of out-of-warranty engine problems or they participate in the competition of who can over-maintain their car the most.

 

[SubieRubyRoo]

The thing with catch cans is that the liquid you see in it, is not what goes through the engine. All of that is suspended as tiny droplets, it’s harmless. The catch can condenses all of that into liquid and all of the sudden, it looks like scary stuff, especially when water mixes with oil.

While the water vapor does condense, there’s plenty of evidence that it’s not all oil vapors in the PCV system, but droplets as well depending on the baffles & filters in the circuit. Even if the oil is in a droplet mist, it’s going to land on and coat whatever it touches. I’d prefer in my engines to have that be the catch can rather than the intake runners and valves.

 

[Dave Hess]

I got a CC on a 5.0 Mustang and it catches a nice amount of oil every 5K miles when I drain it.