Too much oil = DOA

On the Prius we do that by running over blind pedestrians.

Tom

 

I'm no longer convinced putting in 4 US quarts will cause catastrophic things to happen.

The dealer did the first two oil changes, I did the rest of them, putting in 3 litres all the time. Guess what? I still have that little "puddle" in the intake manifold

Out of curiousity, I used a very long swab - the kind used to clean some electrical assemblies - and dipped it in the puddle, with my other hand holding the throttle blade open

The stuff in there smells strongly of evaporated gasoline. Very little of an "oil" smell to it

 

Well then, your puddle is gasoline and not oil, true? I do wonder how it got there [no longer; thanks, Patrick!], but one can't conclude from that observation that overfilling the oil would *not* cause a problem.

 

Since the Prius engine uses Atkinson cycle, the intake valves stay open beyond bottom dead center, which forces some of the air/fuel mixture back into the intake manifold where it condenses and pools.

Regarding the use of 4 US qts when refilling engine oil, I used to do that with my 2001 and had no problems. I've cut back to 3.5 US qts, after joining Yahoo Prius groups & PC and getting sensitized to the engine oil level on the dipstick - but I would not say that this makes a noticeable difference other than to slightly reduce my purchases of engine oil.

Hi Jay,

Try holding a lit match to that swab and see what happens!

 

It burns slowly. Yeah, actually I tried that and it wasn't the sort of FWOOOOFF you get from fresh gasoline

 

I am curious what passages the excess oil would take to get into the intake?

 

A lot of us have theorized the PCV system may introduce excess oil

 

Isn't one end connected to the overhead cam/valve cover? If so, that would mean the Overhead cam/valve area is collecting the excess oil somehow and the excess fumes collecting in the intake, no? Then, why would the oil not drain back to the oil pan as it would normally? and why would the excess oil end up there in the first place?

 

The PCV valve is bolted into one corner of the engine valve cover. The PCV air intake is connected to an adjacent corner. A baffle runs along the bottom of the valve cover to prevent oil splashed around by the camshafts from getting into the PCV hoses.

If engine oil is rapidly pumped into the engine oil filler hole, maybe some of the oil might flow along the baffle and end up in the PCV hoses. That is the only way that I can visualize oil entering the PCV system; but this is not related to an overfill necessarily, but rather a rapid flow of oil into the engine.

Attached photos of my 2001's valve cover. The first photo shows the baffle under the cover. The second photo shows the corner of the baffle below the oil filler opening, and the third photo shows the top of the cover; you can see the PCV valve mounted in the upper right corner and the air intake tube located in the bottom right corner.

 

Grease the suspension? Are we talking 1960s cars? My 1968 Toyota Crown has grease points, but I can't think of anything much more recent from a quality manufacturer that has.

 

My 1985 Jaguar XJ6 VDP had grease points in the suspension, driveshaft, and wheel hubs, and the Jaguarphiles that I knew actually thought this was superior to modern-design sealed parts.

Oh wait, your reference is to quality manufacturers? Never mind...

 

I was thinking more of heavy oil vapor instead of actual liquid ingestion. Eg: extremely cold weather operation will put a lot more vapor into the PCV system.

There is obviously vapor introduced into the intake system from the PCV. I was surprised I had to clean the MAF and throttle body after only one year of driving my FJ. It doesn't get used much , and will sometimes see very short trips in winter conditions

You would think that two hour drive out to the hobby farm would clean out the intake system. I guess not. At least the MAF is very easy to clean, and TB is relatively easy to clean, on my FJ

I used to think that perhaps oil overfill would introduce more oil vapor into the PCV system. I no longer believe that. The only situation I can think of causing liquid ingestion is the grease monkey using a central oil filling system, and the system pumps the oil in so fast it can't drain into the block quickly enough, flooding the head and running into the PCV system

 

Honestly, I was a bit surprised to notice my FJ Cruiser doesn't have any zerks for the ball joints or tie rod ends. It does have u joint zerks.

This can't be much of an issue, I haven't heard of any issues with early ball joint failures. The suspension is the same as the Prado in your market

 

That is exactly what I was visualizing. But, with this setup then, the excess oil is in the oil pan, not in valve cover area and don't see why the oil pump would pump more oil up there just because there is more oil on top of the oil pump; that would make no sense.

So, as was surmised in another post, vapor collection up there, independent of the oil quantity in the pan.