2010 Prius 100,000 Mile Preventative maintenance Items

I don’t think it matters much, if at all. Existing PCV valve in ok condition, or cleaned, or new, are all pretty similar in what they deliver to the intake.

Besides fit they can have different performance, flow rate. I’d stick with dealership parts department purchase; it’s under $10.

 

that’s about right. Some feller did the cleaning and put a catch can in. Weeks after driving, it pooled up again.

 

there’s a thread about that here, and just about everything you can think of. Except for pulling the 12v lead before EGR cleaning, not one thread or tutorial say to do so.

 

Something I'm realizing is that with a horizontal PCV valve, it will only ever close during a backfire. Vertical PCV valves will close when the engine is off due to gravity. If there's pressure in the crankcase, it will open a vertical valve even with the engine off. BUT...I wonder if having a horizontal valve that stays open during engine off allows more vapors to flow from the crankcase to the intake compared to a vertical valve.

 

PCV valves have an internal spring that keep it closed up to some pressure threshold, regardless of orientation I think.

 

Not the supposed OEM one I just received. When I look at it on its side, the little plug bit is slid away from the engine-side opening. When I turn it vertical, it is closed. Maybe it's defective?

 

I’ve never fully got my head around it, but I don’t think orientation should affect its operation. Here’s a wiki article:

Crankcase ventilation system - Wikipedia

And if you search for the text string:

The PCV valve controls the flow of crankcase gases entering the intake system

it goes into details about what the valve does, under varying intake manifold vacuum conditions.

 

So a PCV valve can close (or almost close) in both directions, both under high vacuum and under backfire or engine-off (if gravity assists it). Look at this. With a horizontal PCV valve the condition on the left never happens.

 

I’m not sure. Looking at the leftmost pic, the “bullet” shaped internal thing looks to be encased in a spring, that could keep it pressed against the bottom opening, regardless of orientation?

Granted though: the one you pictured seems to flop open/close easily.

 

Right, that's what the picture shows but not what the PCV valve in my hand is doing. It only does the leftmost situation when oriented vertically. Anyway, maybe it doesn't matter. Maybe the crankcase heat creates enough pressure during engine-off to still push vapors past the relatively loose bullet. I'm sure that's intentional (whether well thought out is maybe another thing).

 

That’s a brand new Toyota PCV valve? Maybe defective?? It’s very infrequently I’ve got one in hand, but it seems to me they’ve always had a metal bit right behind the internal opening, firmly enough that orientation didn’t matter . Could be “creative” recall on my part.

 

I think I’ll invoke the @ChapmanF ”bat signal”, he usually has this stuff down pat.

 

I didn’t disconnect the 12 volt for Exhaust Gas Recirculation and intake cleaning, don’t think it’s needed. For brake work yes, but that’s different.

 

Hilarious!!! You’re one of the 3 who poo poo’d me for not doing it on the old thread.

 

@Rocky Mountain Priusman i would START with that elusive lower cooler bracket nut. Get it done, and leave it off, for good. Anyway:

It takes a combo of long socket and short extension (maybe 1.5”?), and a swivel headed ratchet is helpful. Snake it in there; the nuts around 3 o’clock, relative too and just beyond the braid-clad coolant line going into the head. You’ll feel it lock on, and you’re in business.