Hi all, new Prius v owner

Did the swap include cleaning the passages in the intake manifold? The whole EGR path should get cleaned.

 

Get a gen 4 engine for $1000 with under 50k on it. Toss it in. No oil burning or head gasket or EGR problems.

Problem solved and much cheaper than putting a bandaid on a junk motor (the gen 3s are decent but too often fail).

 

I have not seen anyone in the Gen4 section complaining of egr clogging or head gasket failure...
At least not yet...

 

I'm not a mechanic but my mechanic has done it 3 times now (possibly 4)...Charges me about $800 labor.

We sold a Prius V and motor blew shortly after so we helped that guy out and went half on repair....and had a couple personals.

Again, not a mechanic but there is a very nice PDF file on this forum. Only 1 or 2 differences. One has to do with disconnecting a colored wire and putting it in different position...and the other has to do with heating up and rotating something with exhaust manifold (?).

Other than that plug and play lol.

They fixed the piston rings on gen 4s because of the widespread and well known oil burning problem....if I am not mistaken....

They are the same motor just improved upon. Oh, you don't need a parts car, you literally just need your car and the gen 4 engine.

We (and by we I mean my mechanic -- has done the job about 4x this year).

https://attachments.priuschat.com/attachment-files/2020/02/182535_Gen_4_Engine_into_Gen_3_Prius_Partial_Guide_-_by_PriusChat_member_Alexander_D.pdf

 

There are several improvements in the Gen 4 that have to make a difference:

Improvement 1) EGR coolers have been around a long time on big trucks, so the concept of an EGR cooler is not new. The EGR cooler in the Gen3 takes its Exhaust Gas from the Exhaust Manifold, before the Catalytic Converter. This is where most cars got their EGR gas from before EGR coolers were implemented. The Gen4 takes its gas after the CAT. This makes a huge difference.

Taking the exhaust after the CAT means the Gen4 is dealing with less hydrocarbon content to cause clogs. It also means the exhaust gas has cooled a little bit, and at a lower pressure going into the EGR cooler. As a result, the Gen4 EGR cooler can have larger passages, that are less prone to clogging.

Improvement 2) The Intake Manifold was redesigned. Pre-2015 IMs have the Exhaust Gas coming in from the left side of the engine, and a single straight passage feeds the smaller passages to each cylinder with a right angle bend. I will refer to this as cylinder #1 * (furthest from from the EGR inlet). Cylinder #1 EGR gas has a longer path than Cylinder #4 (about 16 inches longer). The gas going to #1 is cooler, and slightly reduced pressure. It is where the crud builds up first. When that cylinder's passage plugs up, that cylinder burns hotter. That is why the HG goes on that end of the engine first.

When I cleaned my 2013 v at 94K, I confirmed that the furthest Cylinder passage was more plugged. It is also the hardest to clean. The problem with this uneven distribution is that the EGR performance test tests all 4 cylinders together. Cylinder #1 can be plugged, and the other 3 cylinders only slightly plugged. When the EGR test runs, the aggregate flow of all 4 cylinders may be within limits to prevent a P0401 code, even though Cylinder #1 is starved for exhaust gas, and running too hot.

At some point, Toyota changed the path of the EGR gas takes in the intake manifold. I think they started using it with the 2015 Prius V. This new design uses a "tournament style" EGR gas distribution path **. The distance the gas travels from the EGR valve to each cylinder is the same, although now each path now has 6 right angle bends, instead of just one bend. The path is probably twice as long to boot. This "tournament style" IM is almost certainly used in the Gen4 engines.

Toyota spent a lot of engineering effort to make this change, and the IM is a far more complicated (i.e. expensive) hunk of plastic to manufacture. They would not have deployed this new style IM without some testing to see if it improves the problem. At very least, clogging should happen evenly on all cylinders, and the P0401 code should be thrown before a HG or piston blows.

Improvement 3) Improved oil consumption rings were implemented in models manufactured after a certain date in the 2014 model year for the Prius V. Less burned oil, less hydrocarbons to clog things up. This should have been a no brainer.
​

In conclusion, the Gen4 might still have EGR clogging issues, but the P0401 code will be more likely thrown before any serious damage occurs. I would also assume any clogging would happen at a much higher mileage.

* I am not 100% certain if the cylinder on the passenger side of the engine is officially cylinder #1. There is a crankshaft pulley with no belt on it on that side of the engine. That makes it a pretty good guess as cylinder #1

** IIRC @rjparker posted something that described this redesign with pictures, but I can't seem to find it.

 

That experiment has been done thousands of time, with the same result, it doesn't work.
Only a very temp thing.

The accumilator is doable. I saw partial video of removing the inverter to get to it.
Unless you have a lift to get it in the air and remove the suspension...

 

Yea, I know.....

The question still is.... Has the Gen 3 egr cooler clogging problem been resolved in the Gen 4 egr system?
Only time will tell. I havn't heard from anyone with 4th generation having a head gasket fail like the Gen 3.

 

Which really points to the 3rd gen “smoking gun”.

 

The house cleaner put it up
Did 4th Gen fix 3rd Gen? | PriusChat

 

I have seen a product that is old school work for months without clogging things but they did multiple flushes to ensure no coolant remained. But it did fail because none of the underlying causes were rectified, primarily the excessive oil consumption. When it did fail it was engine time instead of just a head gasket.

So for scamming flippers it is a tool of the trade. Sell off the car and let the new buyer suffer several months later. As a result, when we see buyers ask for advice before purchase, I say no. And then there is a chorus of owners who jump in and suggest otherwise because they have not seen it with their own eyes. Until they do.

 

What are the miles and price you would want, approximately, if you were to sell? I have a 2016 motor sitting around waiting to drop in a gen 3 (did the gen 4 swap and car got rear-ended, pulled parts/motor and scrapped)

 

Interesting video .... showing that the head gasket material works, but you may very well only get 10K miles out of the fix. Also of note, that it may very well be the gasket is just fine, and it might just as easily be the head got warped - that the sealer is temporarily making allowances for, until the 10K mile limits (or so) finally expire.
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