Engine Rebuild Gen 3 or Gen 4 Engine?

Sounds pretty good

 

Why? Head gasket failing, head problems (valve stem seals, cams, whatever), or block problems (excessive oil consumption, pistons or bearings going)?

also, how many miles on it?

Addendum:



^ this is the revised piston ring set, the ones with higher tension, said to reduce incidence of oil consumption, down the road. Still, you could probably just replace rings with original style, and it'd be good for remaining engine life. One odd ommision though: I think you have to also replace the pistons; you can't put the revised rings on the old pistons, maybe revised ring dimensions requiring different piston grooves. But there's no mention of the pistons being swapped.

Attached TSB has more info.

 

The list shows pistons. I think a rebuild is the smart solution on an early gen3 with design flaws from the factory and is absolutely what I would do. With a rebuild, you are not going for "remaining engine life", its a new 200k miles for the car. Same argument we make on hv batteries, used or new, short term or long term fix. How about brake boosters? Is used good enough?

 

Oh yeah, you're right. Assume revised part no's, would have to be.

If oil consumption is not bad, you could just replace head gasket. Maybe the economics of that are not that advantageous though, labour about the same?

 

One thing, you can get a rebuild kit from Toyota that has pretty much every gasket, O-ring, and seal. It includes a new (Toyota) head gasket. Just my uneducated and inexperience opinion, if I was ever to do this, I'd go for that kit, and new Toyota head bolts. (Part no's in attached.)

Gasket kit: 04111-37315
Head bolt: 90910-A2011

Amayama shows the gasket kit fairly reasonable for me, in West Coast Canada:



They're out-of-stock for the head bolts though.

 

Most agree when using metal head gaskets in these engines the best choice is Toyota. It is unlikely hg fails are caused simply by the gasket material. Clearances, cooling and carbon caused by blowby and pcv systems are more likely but the Toyota mechanics I know suggest there is no magic bullet or even a good explanation for the hg issues. We do know similar problems happen on Rav4s and Camrys of the era.

What seems obvious is the extensive changes made on the gen4 1.8L engine. Most provided reliability and mpg benefits.
Did 4th Gen fix 3rd Gen? | PriusChat

 

I think if head gasket manufacturing quality or material was the issue, our gen3 engines would not last 125k-200k miles before failing. The prime suspects are excessive blowby and carbon build up. In the same police lineup are liquid slugging due to the pcv and thermal cycling loosening head bolts. Pick your poison.

However if your mechanic is sold on Fel Pro head gaskets and is offering a long guarantee, go with it. Don't risk his good will by overriding his expertise. You may need him later.

 

See if there's a ways you can compared OEM and Felpro head gasket in person. You should be able to figure which one is higher quality that way.

 

I’m totally unsure, just have a play-it-safe mentality.

the kit is invaluable for all the extras: if a machine shop goes over the head for example, they can use the valve stem seals.

 

Not sure its better but its half the price of Toyota which is why mechanics use them. Probably Fel Pro is just fine and their marketing is certainly better than Toyota's.

Good results is another reason mechanics have not stopped using them. The profit goes from a couple of thousand on a rebuild to zero if they have to do it again which usually motivates a shop to do it right. The new pistons and rings along with a fresh valve job should give you reliability regardless of the head gasket. The real test is 150,000 miles down the road.

 

Very simple to swap a gen 4 in (according to my mechanic who has done it about 4 or 5x). There are only 1 or 2 modifications such as rotating the exhaust manifold and switching 1 colored wire. It is outlined on this forum in a PDF. You can get a 30 to 50k mile 2016 engine anywhere from $800 to $1000. And a competent mechanic can do labor for $1000.

Hope you have good luck on the head gasket job