Excessive oil consumption explained and how to fix it

Does it make sense that a cleaner exhaust gas would result in fewer deposits in the EGR system? If so, then how would one produce a cleaner exhaust.

 

Yay! Another oil consumption thread which we already covered over hundreds of pages of detailed info of rings and egr cleaning. But no OCC mentioned in this one.

 

I think so.

Maybe the aforementioned Oil Catch Can, on the Positive Crankcase Ventilation line between PCV valve and intake manifold, will do that.

I did the works (including an OCC), around 70K kms, in September 2017. Checked the EGR pipe a month or two back, at 81K kms, and it was pristine. I had the throttle body off day before yesterday for a clean: there's an oil "sheen" at the low point of the intake manifold, but not a pool.

The OCC is catching around 100~120 cc per year, and that's with only 8K kms usage.

I don't doubt that the EGR will eventually start to clog up again, but between the OCC and periodic reclean of everything, hopefully that'll break the vicious cycle.

 

Maybe a dumb question, but, if the catalytic converter is subjected to exhaust gas like the EGR system is, why do I not hear of more CCs getting clogged?

 

I dont know where the comparison comes from, but, the catalytic converter and the EGR cooler are two different types of animal and are not related in form or function.

 

They both have contact with exhaust gas.

 

Both the EGR cooler/valve and the Catalytic Converter:

1. Have exhaust gas flowing through.
2. Are subject to clogging.
3. When clogged, cause problems.

CC's have been in use a lot longer, they've worked out the optimum cross-section? The EGR as implemented in Gen 3 is new. For 4th gen it looks like they more-or-less doubled the cooler cross-section, and moved the EGR intake to be downstream of the Cat.

 

So, if you have a Gen3 that does not...yet....show any problems, what to do to stall/prevent this from happening?

 

Drive the speed limit, go up on oil viscosity and keep an eye on the Prius chat PM’s (egr circuit cleanse and oil catch can).

Best thing to do is monitor the dipstick to stay ahead of it.

 

Maybe I'm drifting too far into the weeds, but, what if post CC exhaust gas was used for the EGR system? Would it not be much cleaner? Maybe too expensive too engineer.

 

That's what they've done, in fourth gen. I suppose you could mod a 3rd gen, but a lot of work. With 3rd gen the EGR feed pipe branches off the exhaust manifold.

Memorable @Ragingfit quote from the above: "This came off this engine, so it better fit..."

 

An even dumber question but what if the egr uptake was moved posted CAT?

Might loose a small amount of economy but the oil should be burnt off so no more gasket eroding oil chugging?

 

Thanks Mendel. Good job on finding that video.

 

Plus catalytic converters get over 1000F, they burn off the kind of stuff that sticks to the EGR cooler fins. And EGR valve. And EGR pipe. And Intake Manifold.

 

That's easy.

Big kudos to @Ragingfit for taking the time and effort to document his transplant.

 

Several cars come stock with some sort of OCC, and then it's allowed.

At least with a tightly installed, sealed-style OCC, the only reason it's not allowed is that it's not stock, service departments have no awareness of it, no published documentation, that sorta thing.

 

There has to be a rhyme or reason that some use oil and some don't. I live in Texas where it is hot and a lot of freeway driving. I also use only Tier 1 gas and Synthetic oil. I don't use oil and never had my EGR serviced. Could it be the gas and the heat that makes a difference?

 

Have a look at the EGR pipe; it's an easy DIY. @NutzAboutBolts has a video on it, pinned in 3rd gen maintenance forum.