Oil Catch Can, Eliminate that knock!

THIS is exactly why I removed my oil catch can (after installing updated intake manifold). In the winter and when temps got cooler, I basically had to drain it after every trip to avoid oil gravy being sucked into the engine, and even then, sometimes it still would (and would knock because of it).

UPDATE:
15,600 miles on the new intake manifold without oil catch can and STILL not a single knock. I'll add I'm in the Midwest USA with Winter temperatures as well as scorching Summer temps. 233,000 miles and engine still doesn't burn a lick of oil.

 

Personally, I would consider bypassing it in the winter. I thought it did more harm than good in winter temps.

 

@Coots may I please ask the part # of your updated manifold?

 

@jzchen
https://toyotaparts.mcgeorgetoyota.com/oem-parts/toyota-engine-intake-manifold-1712037054

 

If you want to save some money, look on ebay, just make sure the donor car is from newer model years.

 

To save even more, just clean the intake manifold you've got, lol. I doubt the revised manifold does squat.

 

When I installed my can, I thought "why are they cutting the original hose and needing to use 2 barbs?" so I just kept the original hose by just disconnecting it from the PCV valve and only used one barb.

My thought process was that a barb right by the PCV valve would introduce a piece of metal in he hose that would stick out and interrupt the flow of gasses and be more thermally conductive than the hose and allow vapors to cool on it and then drip back down to the PCV valve.
I put the hose directly to the PCV valve from the catch can.


This arrangement also allows me remove the catch can and reattach the original hose if I ever needed to.

 

I did more than my share of revisions, went back to @danlatu’s method. It’s crowded under there, and any unnecessary changes tend to impact adjacent components. My 2 cents:

Cut the orig hose at middle, leave the 2 ends at orig locations, with orig clips. Those resultant 2 elbows fit well, and can be rotated to various directions, depending on where you locate your can.

Push on 3/8” barb splicers at each cut end, and run 3/8” ID fuel line to OCC. Use no additional hose clamps on the new connections; they’re not needed with barb splice, and can actually be detrimental to the hose ends.

This’ll give you a neat, efficient layout, nothing crowded.

 

Skimmed a few pages of this, has anyone thought about running one that drains back into the crankcase?

Its a common thing on subarus. There are ones with a drain on the bottom that the pan gets drilled/tapped for, others that go right over the oil fill port

 

Why would you want to put it back in the engine? It's very minor, and it could
be contaminated with moisture... You certainly don't want that in the engine oil.

 

One negative: the goop that collects in oil catch cans tends to be about 50% water, pretty sludgy looking. Maybe best to just leave it in the can?

 

The water evaporates.
Similar to all the comments during the first cold month of the year when everyone posts pictures of the white milky stuff on their fill cover asking if the HG is toast.

4runners, subarus, etc all have the same issue.

 

A “catch can” with a return is better but is more expensive to implement properly. It is more commonly known as an “air oil separator” and often is built into the engine, including some later Toyota systems.

Both devices prevent crankcase over pressure which can blow seals and both prevent old school atmospheric discharge of the fumes.

Often a stock gen3 will build up significant fluids in the intake manifold. Good engines will collect very little fluids; however many gen3s are burning oil and or have excessive blowby which can quickly fill a lower volume catch can. Careful monitoring of simple catch cans is required on a worn engine or they can slug the intake with fluids.

Integrated air oil separators perform a catch can function and use engine/coolant heat to keep the fluid from gunking up and allow heat to evaporate moisture. Better aftermarket separators have better filters and often have heated coolant passages as well.

The best solution is a rebuilt engine with revised pistons and rings when significant fluids build up in a gen3 intake or catch can.

 

Not when it mixes with the oil....

 

Where does the oil in the catch can come from? Why cant it go back there?

 

Been awhile since I had to make one of these.
My EGR wasn't plugged, but the amount of oil in the intake was more than enough to be concerning

 

So the 3/8" or 10mm ID tube will do the entire system. from the PCV to the can and back to the original tube.
10mm or 3/8" Barb would then connect to the original tube large side.

if I cut the original tube in the middle I have to go with 8mm barb
wouldn't that be lose on the 10mm tube?

Also do you recommend this mod in north east weather and winters?
should I go with a larger can, I see the average size is 300mL ; I saw some 700mL capacity

I just got concerned since I read the post with issue in cold winters.

Just got my Prius v 2012 with only 75K miles but not sure about the maintenance History so I am deciding what I need to do on it to be comfortable for the next 50K miles...

 

3/8” barb splicer works fine with original tube cut at the middle.

not sure. I never had a problem on west coast Canada, in Vancouver region. Presume your concern is freezing? Location of the can might be a factor, but not during cold starts, only after warm up.

last time I let mine (have two Moroso 85474 in series) go a full year, roughly 5000 kms (3000 miles), and both cans had 50~100 cc. I’ll double check; for now pic attached. IIRC bottles shown are about 40 mm OD, hot sauce bottles. Flow direction is left to right: left is mostly oil, and second the inverse.

EGR cleaning would be my prime concern, it’s the Gen 3 Achilles heel; my conviction is it’s the cause of the head gasket failures. See top two links in my signature; on a phone turn it landscape to see signatures.

 

I have not seen this discussed maybe missed it, but came across it in a video on YT.

Relocating the PCV valve to a higher position via a hose or all the way to the outlet of the Oil Catch Can

the PCV valve is M16-1.5mm thread, which is the same as many oil catch cans, some even come with a M16-1.5mm to 1/2" barb connection.

Can you think of a good reason not to it that way?

Engine PCV plugs in to a threaded Female M16-1.5mm >> connects a Male M16 x 1.5mm to 10mm Barb instead of PCV >> 100mm Fuel line Hose to OCC input>> OCC >> Install the PCV on the outlet of the Oil Catch Can >> 10mm Hose from the PCV on the OCC >> Intake manifold direct connect the 10mm or use 10mm Barb to 10mm Barb and connect the new hose to the fat part of the old hose.


PCV is supposed to let the engine release extra pressure, why would it matter if the PCV is so close to the engine to get clogged with garbage... let the gasses come all the way in to the OCC cool down and get rid of the garbage and then go through the PCV back to manifold if the pressure is high enough.

as a benefit, the PCV valve will be a 2min job replacement in the future with this setup.

 

Ah, that's over my head. I've left the PCV valve as-is, cut0half of the original PCV hose connected to it (with orig clip, 3/8" barb splicer pushed on, 3/8" fuel line (SAE30R7) pushed onto that splicer, other end to first oil catch can intake, short length of fuel line from first to second can, and yet more fuel line from second can exit to 3/8" splicer, pushed onto other cut-half of the orig PCV hose, which connects to intake manifold (with orig clip).