PCV Valve replacement: why not removing the inverter coolant reservoir?

Don't waste your time with the PCV valve, they don't ever go bad on the 2nd gen Prius

 

It's right up on top of the valve cover; is access that crowded? One thing: take the hose off it first, and use a closed-ended wrench or socket wrench to remove. Using an open-ended wrench you may put a hole in the valve cover casting when it breaks loose. If you do use such a wrench (to make it easier remove the hose or whatever) be very cautious, and/or lay a strip of steel gauge plate over that zone of the valve cover.

Repair Manual info attached.

 

Thanks Chap. I wouldn’t know where to find that sketch.

 

I generally do some search like this and scroll until I spot that image or another one you did with dimension lines added to a photo of a wrench, which is in the same thread.

 

Getting to the PCV valve and replacing it isn't going to give you the "why" (on the 2nd gen Prius). It'll just give you some exercise in getting to a difficult part that doesn't need replacement.

 

PCV valve is cheap to replace (under $10 USD), and I believe new ones come with thread sealant applied. Cheap experiment anyway.

 

The reason I tell you this is because I've removed at least 10 of these in my years of owning multiple Gen2 cars, not once have I found a bad PCV, they all rattle and did their job. And I've talked to many Prius mechanics that have the same experience with the Gen2 cars.

But as mentioned above, there is no harm in changing it, go for it and have fun.

 

The PCV valve on the gen 2 is in about the most inconvenient place imaginable while still being "near the top of the motor". Conversely, the other end of the tube attached to the PCV is very accessible. I wonder why they didn't put the PCV valve on the accessible end of the tube? My best guess is that in that configuration the tube would gunk up with oil before it reached the PCV. Either that or they just didn't care how hard it would be to service the PCV.

For the OP, I believe the consensus for "why these cars burn oil" is that the rings get stuck, usually because oil changes have not been frequent enough. Fixing this sort of problem with additives and such is a black art of dubious value. It wouldn't hurt to change the oil a little more frequently, to see if constant exposure to pristine oil can dissolve some of the gunk and release the rings. It probably won't help though.

If it is the rings the real fix is a ring job. Lot of work if you do it yourself, or a lot of money to have somebody else do it, your choice. Unless it is burning a quart every tank it is usually cost effective to keep adding oil.

 

This PCV valve is very simple to change with a ratcheting box end wrench!


iPhone ?

 

Piston rings are the most common reason for oil burning followed by valve stem seals. Pcv valves stuck open is sometimes cited as a possibility but is rarely the cause. Since it is cheap go for it. But don't discard the old spark plugs before having an experienced person look at them for signs of oil burning.

The same experienced mechanic can perform a dry and wet compression test to help isolate the rings or valve seals. Wet means adding a little oil to each cylinder to restore weak compression. Generally that will point to the rings. It is somewhat common to have bad rings and valve seals. The typical "blue smoke" diagnosis does not work on modern cars since the catalytic converter eliminates the blue oil smoke.

However excessive oil burning over an extended period can ruin the catalytic converter by clogging it up. At that point (rarely seen) the engine runs very poorly. Usually its bad rings causing excessive oil consumption which requires a rebuild to fix. During an engine rebuild the head should also be machined as necessary and new valve seals installed.

Finally Toyota often suggests it takes a quart every 1200 miles or less to be considered excessive. Obviously good engines burn much less than that.

 

I think the coolant reservoir is formed with a plastic tube on the inverter side, that inserts into the inverter and seals with an o-ring. The fasteners keep it locked in place. If you remove the reservoir, it's just like popping a hose off and it will drain. Not 100% sure, but that's what I seem to remember.

 

TMR is right, the second connection is directly to the inverter, with an O ring.

If there were only one hose connection, how would the coolant circulating out through that hose be returning to the reservoir?