Oil Catch Can, Eliminate that knock!

Besides the reasons in the reply above this one, there is another reason, equally or more important. Your Prius ICE won’t run correctly if the can is vented to the atmosphere, as the line it’s tied into is a major intake manifold vacuum source.

 

Could Toyota have designed a PCV system that doesn't dump an oil/gas/water oleo into the intake? Or at least really minimizes it?

I'm thinking an effective oil catch can system, part of the factory install, preferably self-emptying, back into the sump.

They took a crack at it, with that labyrinth plate the PCV valve screws into, but it's mostly ineffectual.

 

Doesn't the OCC catch all kinds of goop that you wouldn't want back in your sump? I haven't installed mine yet, but the pictures I've seen of the stuff that others have caught looks nasty.

 

Yes it does. Still i's technically illegal (a mod) and requires regular emptying.

 

Was wondering about the outlet hose or even the benefit of the hose being larger coming out of the PCV Valve. Was originally planning 5/8" outlet hose from the OCC... though just got the 3/8" fuel and PCV rated rubber hose. Now, I am going to think about this some more before I install... hhhmmm...

Neat air intake mod.

Was wondering the same. I recently bought some no-see-um screen for the windows I leave open. Was wondering about using that like maybe super gluing onto the windshield cowling underside at the intake. The cabin filter actually came in the mail today too. Good idea with just regular window screen also. Wondering what the filter is going to look like when I check in the morning?

 

Bought my Prius in September with 25k miles. Thanks to this forum I installed an oil catch can. I emptied it after 1K miles and there was 1/2 oz of black watery liquid. Will the OCC eliminate or delay the need to clean the EGR system around 120K or is it just for the startup knock in cold weather?

 

I look at the Oil Catch Can as an incremental preventative measure; would still clean the EGR (and intake manifold). 120K might be a bit long too; I'd say do it by 100K. I did ours around 70K kms, don't regret it. The first time is the hardest: once you know the tricks it'll go easier next time. Leave the bottom cooler nut off, save the grief of having to battle more than once. Remove the stud at that location too if you like, makes it even easier to remove next time I think/hope.

A couple of tricks:

Leave the throttle body coolant hoses attached; they have plenty of play, no need to spill coolant there.

While the EGR removal does require disconnection of coolant hoses, if you drain 2 liters/quarts from the rad (into a clean container) it drops the coolant level below the EGR system, leaves everything dry. When done, pour the coolant back into the reservoir. For 2010/2011, leave the bleed valve open when refilling, till coolant starts coming out. For 2012 onward (without bleed bolt ): just leave a topmost coolant hose disconnected, till coolant wells up and overflows, then quickly connect.

 

So then how come no removing the 12v battery lead cable? You guys told me that it was common sense and I should have removed the cable from the battery before pulling the manifold. Don’t say you never said that.

 

I never said that.

 

So I just cleaned over 1/2 cup of watery oily sludge out of the bottom of my intake and installed an oil catch can a few days ago. The knock on a cold start up is hit or miss and by that I mean it pretty much does it all the time but some start ups it continues for several seconds shaking violently.

I didn't remove the intake entirely but I did use napkins up as far as I could, waited 24hrs for more to slide down to the well, cleaned again, then reinstalled the throttle body and plenum.

This 2011 gen 3 has 248,xxx miles, had a hybrid battery replacement 30k ago and head gasket(head needed milled too)15-20k ago. Other than the shake on start up it has been good. As we get colder weather the shake continues to get worse it seems even after the catch can install. Any advice?

 

It’s possible that you still have a misfire caused by a failing ignition coil. You probably need to go ahead and pull the intake and make sure it’s all clean. There was also a revised intake manifold that was also supposed to help prevent the knock.

I assume that at the time of the head gasket replacement, the EGR cooler was cleaned as well, if not you should probably get that done too.

 

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I kinda doubt it's a coil since it only does it on cold starts...at least that hasn't been my experience with failing coils. I just pulled the throttle body again and there's over a half inch of sludge again...almost as much as last Sunday/Monday when I cleaned it and installed the catch can. The line going into the intake from the catch can is clean and the pcv is def putting out some crap into the can/jar.

I suppose I'm going to have to take the entire intake off then and clean it. Where on earth is all of this crap hiding if I've removed the source with the catch can and have another 1/2+ cup of sludge?

SM-G981V ?

 

The PCV valve plate on the block is probably loaded down with that mess. I didn’t find that much when I first got my Gen 3 at 209k that was actively leaking from the head gasket.

 

Are you suggesting another blown head gasket with this much muck in there after having just cleaned it out and installed a catch can?


SM-G981V ?

 

One possibility is that the engine is not achieving operating temperature. Thereby allowing condensation to accumulate in the oil.

Is the coolant level stable, and unchanged since the head gasket change?

I installed my Gen 3/4 engine July 2017, and have recently crossed the 25k mile mark since change. I have not seen that level of muck accumulate in my catch can. Never more then a couple of ounces between oil changes at 5k.

 

If you haven’t removed the intake manifold the small EGR passages (one per port) are still as clogged as ever. Ditto for the EGR components: pipe, valve and cooler:

At 248k with neglected EGR you might as well just change the head gasket. You could do leak down test to confirm, but it’s pretty much a certainty. And clean the aforementioned after.

 

The head gasket was done 15k ago and the head was milled as well because it had a warp. It was a buddy of mine's car that he had gotten knowing it had the head gasket blown. He replaced the gasket, blew the new one...took it apart again checked the head, kicked himself for not checking it the first time, had the head milled, 2nd new gasket kept it for maybe 10k miles and I bought it from him.

I don't know if he would have cleaned any of that out when he did the work because he's not a Toyota guy and def not a prius guy. I asked him if he knew anything about the intake design issue, oil catch can use, and pcv valve throwing sludge and said he hadn't heard of any of that during his head gasket saga.

SM-G981V ?

 

Yeah if the EGR circuit is not cleaned with the head gasket change, I’d “speculate” the new head gasket will be prone to failure sooner than later. The EGR clogging rate is exponential, in other words it starts gradually but accelerates.

A new head gasket without EGR cleaning has been “dropped in the deep end”.

 

Since he's not a Prius guy, I'd bet the EGR system has not been cleaned.
Not pulling the intake manifold to clean it is like pulling the oil dipstick and wiping it off to change the oil.

To do the job correctly, you need to pull the intake manifold and gunk it down and rinse it out.
And get a bore brush for a .22 gun and run it through the 4 holes you can access on the manifold where
it connects to the head.

Pressure washer and oven cleaner will CLEAN out the cooler. Don't use the oven cleaner on the egr valve though.
Brake or carb cleaner with a brass wire brush will do a good job.