Oil Catch Can, Eliminate that knock!

Looks like you can't miss it.

I started a thread in 4th gen, asking if anyone was doing OCC. I'll post a link to this.

 

Great idea. Some gen4 here may be at their 100k already. Taxies and uber with gen 4 may be be there by now . 2 years on the road.

 

@soldierguy is getting close, I believe. He has a long commute.

 

Since they are in our geographical area, I offered my services up to help understand if the egr circuit is improved from the Gen3 with the relocation to after the catalytic converter .

Still waiting to hear back.

 

Still, there's no upside to waiting till 100K miles for an OCC. Well, except concerns about jinxing warranty, which is really too bad.

 

After a year mine has only 12K miles. I am a little concerned about the WAF (wife acceptance factor) of doing this for little or no immediate benefit to us.

 

don't tell your wife/
if my wife would know what I did already to her subaru to extend its life, she would probably be mad at me..../

 

Your secret is safe with us... what was it?

 

She can read his posts

Plane bound for island paradise diverted after women discovers husband's affair mid-flight

 

occ, oil/gas/atf/radiator fluid additives, signal lights as drl's, led hi-beams, interior lights & tail lights all leds, brake light flasher, signal light flash speed.....
for my wife a car is nothing more than a tool to get from a to b, as long as it does that, she has no interest at all in the details..../
except she doesn't want neone to screw around with it, because in her opinion cars come perfect from the factory/

 

My wife was raised on a farm so she mechanically knows her way around pretty good.

 

@danlatu . the potential of carbon build up is still there on the gen4. I dont see the engineering improvement aspect. Just by removing and relocating pipes? Pcv valve is at same area so they obviously think it is right. I think you mentioned before that egr cooler is mounted at a higher point now.
Does gen 4 has same p/n for egr cooler? Egr pipe? as with gen3 @Mendel Leisk.
Digging deeper into it lile hoses and pipes diameter or material used may give us an idea of where did toyota engineers decide to improve desigh. They obviously know better and obviously know this problem is real.
@mjoo ?

 

The EGR on 4th gen connect to exhaust downstream of the catalytic converter, whereas on 3rd gen it's upstream. The part no's look to be all different:

EGR System for 2010 Toyota Prius | Toyota Parts

EGR System for 2016 Toyota Prius | Toyota Parts

Here you can see the revised 4th gen exhaust manifold EGR inlet:

Exhaust Manifold for 2016 Toyota Prius | Toyota Parts

EGR inlet highlighted in yellow, downstream of CAT:

 

There must be other reasons you're keeping her...

Posted via the PriusChat mobile app.

 

I haven't really dug into it yet, although I did take a peek down the throttle body a few days ago. I'm at roughly 82,500 miles now, or somewhere in that neighborhood...the miles pile on quickly!

Anyway, I saw what looked like a thin coating of liquid on the inside of the intake manifold...just enough to make it shiny. Throttle plate was clean on both sides. But honestly, I'm not too worried about what I saw in there.

Here's why I'm not worried. There's a lot going on in that intake manifold. EGR sending exhaust fumes (there are tiny particles of stuff in those fumes), PCV sending oily fumes into the manifold, and because the engine itself is an Atkinson cycle engine, the intake valves will allow part of the air-fuel mix back into the intake manifold on the compression stroke, to effectively reduce the compression and reduce pumping losses under low-load conditions. Let's see...exhaust particles, oil fumes, and a little bit of fuel, and all I have is a thin film of liquid on the manifold? That's not too bad to me...I was fearing a VW TDI-like sludge thickly layered on. Also, I know it can't be much oil that's getting in there...I have never seen the oil level drop even the tiniest bit between oil changes.

Granted, I haven't looked at the PCV valve or the lines leading from the PCV to the intake manifold, so that could be gunked up, although given the relative lack of stuff visible downstream of the throttle body, I wouldn't expect a lot of garbage in there.

For now, I'll keep using top-tier gas, and I'll keep tossing some techron in the tank now and then as well. Maybe around 100K or so I'll look at the PCV.

 

Since an oil catch can doesn’t sound like it is in your near future, what about a trip through the egr circuit ?

 

I don't see a need at this point. If I had seen sludge thickly coating the manifold walls, or if I see some nasty stuff at around 100K, I might look at a catch can, but not mess with EGR.

My logic is this. To make sludge, you need at least two elements: quite a bit of PCV oil ending up in the manifold (or some other liquid), and a lot of fairly large exhaust particles being sent into the manifold. I can't do anything at all about fuel ending up in there due to the Atkinson cycle engine, so that's off the table for trying to address. EGR...I'm not too worried about EGR. Since the Prius engine is not direct-injected, the exhaust particles are very likely small...direct-injected and diesels emit larger particles, but not regular port-injected engines. Plus, in order to address EGR, I'd have to mess with emissions components, and I'm not interested in doing that because I do not want to pollute more than I have to. I would be ok with adding a catch can, if I see the need later on...although PCV is part of the emissions system, it's really there for evaporative emissions. A catch can doesn't change that, as long as you keep it sealed by not using the breather element.

So I'll see as I continue driving. For now I'm not sweating it. Maybe sometime in the spring I'll add a catch can. The challenge is finding the time to do it!