Oil Catch Can, Eliminate that knock!

I couldn't understand my own question, a few days later, lol. What I was wondering was: where on the engine block is that leaking? The pictures of the leaks are close up, hard to judge just where they are.

But now, looking more carefully at the overall picture, I think I understand:



The area I've highlighted in yellow is a separate plate. There is a labyrinth passage behind there, basically to act as a built-in Oil Catch Can (though not that effective). The Positive Crankcase Ventilation valve screws into it, as you can see. The seal between that plate and the engine block is a Form-In-Place gasket. It could be that seal is failing?

There's some info on the FIP gasket application, bolt torque, in this:

 

You should empty that OCC every oil change, or at least every other change.
The idea of OCC is to keep that stuff OUT of the engine.

 

When to empty will vary based on climate and miles driven. For me, during the summer, it can be extended to about once a month. During winter driving, it requires emptying every week. Otherwise, water condensation will fill it completely full. And this can freeze.

I would not recommend an OCC in northern climates unless the car can be parked indoors above freezing. Otherwise, outside parking below freezing will not allow draining until spring.

 

Every week? What a pain, and a mess. Maybe you need a bigger can.

 

In Michigan winter I sometimes have to empty the Ruien OCC twice a week and use a little hot water to unfreeze it. But I think it's worth it. The northern hemisphere has just finished the coldest months of the year and have you seen all the recent head gasket threads?

Pixel XL ?

 

How many miles are you guys putting on, say weekly?

 

100 miles/week most weeks

 

Must be something to do with freezing temperatures? On the west coast, I'll guesstimate ours accumulates maybe an ounce every 1000 kms, in winter, with the creamy look. Through summer maybe half that amount, mostly oil.

 

Nope. I'm in Portland, and I have to empty every two weeks/500 miles if I don't want it completely filling up on me.

I don't have to empty it at all during summer, but I was figuring the winter surplus was due to all the humidity in the air.

 

That's been my experience as well. Around here we get lake effect snow.

 

I use a block heater before first cold start of the day? Might be a factor.

Also we are ridiculously low miles, maybe 500~600 kms per month

 

The OCC I installed is a Moroso mounted on a bracket attached to the cross member underneath. It has a bottom outlet that is attached to a remote ball valve for draining. The valve can be reached thru an opening in the bottom engine panel. It takes less than 3 minutes to drain.

The other OCC install type is accessible from the top which makes the hot water trick doable. However, Wisconsin had a cold winter with -35 F temperatures. Not sure going outside at that temperature with hot water sounds fun. Heat tape maybe a better option.

I definitely recommend an OCC. Anyone considering one should know the potential issue in below freezing conditions. Otherwise it may cause more harm than good.

750 miles per week.

 

No, it's because the water vapor that's always in blow-by mostly remains a vapor and passes harmlessly through your warm catch can into the intake in summer. When the catch can (and associated tubing) is cold, a lot of that vapor condenses.

The need for frequent dumping in winter is one reason catch cans aren't standard equipment.

 

Mine seems to be very effective, so far. Remarkably little oil vanishes.

 

Not sure how feasible this is. I can't imagine it takes longer than 30 seconds from the car start for the catch can to increase temp from 40 (winter) degrees to 75 degrees (summer) with engine exhaust blowing through it.

 

CR94 is correct. Although high ambient humidity does make it a little worse, the main source of water vapor is from the combustion products of gasoline, which are roughly half CO2 and half H2O (by gas volume). The blow-by gasses are cooled considerably by the large surface area and mass of the cold crankcase.

I once had a car in which condensate would freeze in the PCV hose and completely clog it after 10-15 minutes of moderate driving in very cold dry weather. Then the pressure would build up until the PCV fitting would shoot out of the valve cover and dent the hood outwards.​

 

The can and tubing will still be a lot cooler in winter than in summer, even though they may be well above ambient temperature. Therefore, more condensation; very elementary physics.

That's blowby gases being sucked through the catch can, NOT "engine exhaust blowing through it." Granted, those two mixtures have some constituents in common.

 

Bottle on the left, April 2018 - October 2018 (dry season).
Bottle on the right, spans over 5 months, November 2018 to March 31, 2019 (rain and cool winter).

 

How many miles?

 

Hi Mendel, I average 1000 miles a month, although I have no distance record of the dry weather catches (left bottle) it is safe to say around 7000 miles for those 7 months.
Whereas the wet weather catch bottle, I drove 4670 miles for the 5 months from Nov last year to last day of March this past Sunday.

So yeah data is here for sometching everyone already knew, for cool/cold/wet weather your catch can does collect more “stuff” than dry warm months.