Another EGR thread

From my perspective, near 200k with no previous EGR cleaning, head gasket is or will soon be toast.

Swap in a 2016 engine? That route is a bit more involved, and there's been unresolved overheat problems post swap.

How the oil consumption? Too soon to tell?

 

Last link in my signature is the full engine section.

(on a phone turn it landscape to see signatures)

 

I'm not sure what's the full list of sources and which contribute more or less, but the little puddle of gloop in the intake manifold has been a standard Prius feature all the way back to gen 1. The intake-valve timing used to achieve an Atkinson effect means some of the cylinder charge gets pushed back into the manifold on every cycle, including everything that was in that cylinder charge, including fuel and likely some oil vapor or mist from (at least) PCV. It's most likely the heavier fractions of all that stuff that end up condensing in the manifold, with the lighter fractions continuing on their way through the engine later.

If you dislike the puddle of gloop in the manifold, you can wipe or sop or slurp it out, which ensures that the gloop you see there the next time you look will be new gloop.

 

An oil catch can will reduce the amount of oil accumulating in the intake manifold nadir, how much dependent on the can's quality, and even quantity. I doubt it'll do much to reduce carbon accumulations in the EGR system though; a full EGR cleaning at least every 50k miles is my pick. Cursing Toyota for not road testing that problem child helps.

 

If I was comfortable gambling on a used engine, I'd go for a 3rd gen Prius or Prius v engine, preferably one that has the revised pistons and rings. Earlier years have "low tension" piston rings, meant to reduce friction, but in hindsight yet another insufficiently tested by Toyota debacle, they are prone to start letting oil by, usually around 150k miles.

@rjparker has made this graphic summarizing the transition VIN's.

If I was in your shoes, I would try just the head gasket, using the Toyota Engine Overhaul Kit, which includes a (revised?) head gasket, and has every pliable gasket you'll encounter, and those you'd need for an engine overhaul as well, if it came to that. If oil consumption was out of control: pull the engine, and either replace the pistons/rings with the revised, or a new short block from Toyota (which WILL have the revised pistons/rings).

The engine overhaul kit's around $250 USD, the pistons/rings maybe $500 USD, and the short block $2000~2500 USD.

And granddaughter would need a loaner car, as a DIY'r the last thing you want to do is rush.

 

Hang onto the "old" intake manifold.

 

Morning is good time to check cylinders, after having driven the previous day. Driving raises the pressures on the system, and the overnight sit gives any coolant leaks time to accumulate. That why engine shake is most often at first start in the morning, the engine is struggling with coolant accumulation.

 

Egr stumbling and stalling is typically caused by an egr valve not closing properly at low rpms or more commonly due to leaks caused by egr cleanings.

An egr totally clogged or closed won't cause stumbling unless there is a leak from outside air.

It has been attempted over the years by guys performing a gen4 engine swap into a gen3. As I recall it coded. It is questionable if it could be made to fit in a stock gen3.

The standard way to do a gen4 swap is to maintain the gen3 intake, exhaust and egr.

Hybridpit has a rebuilt engine option for a gen4/3 conversion with a gen4 short block, gen3 head (allowing gen3 intake exhaust and egr) topped with a gen4 cam carrier and valve cover.

They modified the head gasket to make the gen4 block ports work with the gen3 head. Uncertain why the mod was needed but it may have improved cooling over other attempts.

The pcv system. Oil and condensed water. Which is why people put a catch can between the pcv valve and intake.

A full catch can will stop pcv flow and blow seals. So you have to watch it carefully, especially if your car is burning oil and has excessive blowby.

Which is why newer Toyota engines essentially have a catch can built in with a drain to the oil pan.

There is no magic bullet with gen3 engines. The best results seem to be one with the revised pistons and rings maintained flawlessly with shorter interval oil and coolant changes from day one.