How do I piston soak? Only 1 cylinder fills up.

I am not sure if you realize that water cooled engines operate at constant temperature no matter how hard you drive them. That's the whole point of a water cooled engine. Except on warm-up it will always run at the temperature pretty closely determined by the coolant temperature, which very closely regulated by the system. Driving hard makes very little difference in the modern water cooled computer controlled engines. Italian tune up is for vintage Italian cars, not your 21st century Toyota Prius with Atkinson cycle engine. I mean go ahead and drive it hard, but don't expect it to respond like '69 Camaro.

Also, do yourself a favor and brush up on how most 4 cylinder engines work before you soak anything or add water to anything in there. It may behoove you to know how the pistons move relative to each other inside the engine you are trying to tune up.

Also, the most likely reason for oil consumption in these cars is piston and ring design, not driving style of the majority owners. And despite what many people say, moderate oil consumption is normal and expected behavior on ICE. The amounts vary unit to unit, but most consume some amount of oil. Unless you are loosing a quart every 500 miles, I would not worry too much.

Pistons will always look black, even on a car delivered to you brand new in the dealership. They will look black after 1 minute of running, no matter how shiny they are before that first minute.

 

STOP listening to the useless marketing crap from the sellers of "snake oil".

A little carbon buildup inside an engine is NOT A PROBLEM. It just is NOT.

Now......if there is a lot, such that your plugs are all black, for instance......you STILL should not worry about the carbon, but about what CAUSED IT.

Obsessing over carbon deposits often causes more harm than good.

 

When I changed the plugs on my 07 at 130000 miles I used a borescope and looked at all the piston tops and they all looked very clean. I clearly see clean metal and very little carbon buildup. Plugs were spotless too. Posted all the pictures on this site.

I wonder what I'm doing that's so different than people with carbon build up on what is a clean running car?

Also my engine doe not use hardly any oil at all between changes. The car has had high quality synthetic oil since it was new and changed every 5,000 miles.

 

Because there often is NOTHING you can do to improve the situation.......short of a complete rebuild.

Why should moderate oil consumption NOT be acceptable ??
Some engines do that when brand new. Not so many lately though.

 

I know what a stuck ring is.......and there are symptoms that are different than general wear due to age.
ALL the rings do not stick at the same time. In fact, a stuck ring is somewhat rare in a well maintained engine.

And as I said, it is much easier to apply MMO through the intake.
I did that on a 1976 GM 350 with excellent results.

 

How do you suggest to apply MMO (or water, or anything, for that matter) through the intake? Add to gas? Misting it into the air intake is not going to work since there is a Air Mass Meter in there. Adding MMO to gas is no better than adding any other "cleaner" to the gas. Numbers of tests have shown those products to be almost non-effectual.

 

For water you can place place a tube on an intake vacuum point. It will suck the water into the intake that way. You just have to start with the tube closed off and slowly allow water to enter. MMO I have no idea. Either way you would want to put the engine in continuous run mode. And you don’t have the option of revving the engine like you do in other cars. You will need a light hand to do it.

 

He might have kept his engine in better running shape than yours was. Carbon is caused by excess fuel I believe. Changing plugs and O2 sensors helps keep the engine at maximum efficiency.

 

Are you mostly highway, longer drives? I'd suspect it's lots of short trips, grocery runs, that make for more carbon. That's a lot of our driving, at least once in a while we're driving 'cross town though.

Not always. I monitored engine temps for a few years with ScanGuage on ours, and found it would often settle in around 50~70C in easy driving. Go up mount Seymour, and yeah, then it went right up, to around 90~95C.

 

First......you do not put just "anything" into your engine, regardless of the method.
Water injection systems really was steam or water vapor.

Once you are pretty certain that you have a stuck ring, you warm up the engine, manually set a fast idle (difficult to impossible with some hybrids) and then SLOWLY pour MMO into the intake. When smoke becomes evident and it runs a little rough, you DUMP the last few ounces in all at once to kill the engine. Then let it sit overnight.

To be perfectly honest, that is an old "shade tree mechanics" procedure for an engine with mechanical valves and a carb.
I do not know if it is safe to do with a modern engine or not.

And any true oil that is added to the gas tends to NOT burn completely and should accumulate in the upper cylinder area and hopefully get to the stuck ring eventually. 2 ounce cans of light oil used to be commonly sold as "upper cylinder lubricant". Another product that wasn't really needed under normal circumstances.

 

MMO will increase compression on a failing engine with leaky rings and it also helps with vacuum leaks.
Ask me how I know.

 

I know how to do it on an old carburetor engine. I was specifically asking about the Prius, which is what we are talking about here. When you say "intake", do you mean fuel or air? Air intake on a Prius has a MAF sensor, which is probably not going to like either water or oil dumped on it. Very expensive to replace and the car will not run very well without it. In case of fuel intake, would you inject it into the fuel rail under pressure somehow or just add it to the gas tank? It seems pretty far fetched, the whole thing. On the Prius, which is the relevant case we are discussing here.

 

Can you elaborate on how to use MMO in the Prius for this to work? Add it to gas? Oil? Air? I am trying to understand.

 

The MAF sensor is well upstream of the throttle body. And yes, you definitely would not spray things before that. You can remove everything but the last section of hose connecting to throttle body, or that as well, shoot whatever in right at the throttle body.

 

I reckon that the car will not run well (or at all) if you open up the air intake. I have not tried it, however.

 

I think it'll run fine. There's no vacuum lines connecting, all the way to the throttle body. It'll just be a little noiser, I think. I haven't tried it though.

Addendum: there's is hose from top of valve cover to intake, and the MAF sensor. Hmm, not sure now.

I think you'd want to keep the cable to MAF sensor connected (even though it's pulled off, off to the side), to avoid a Check Engine Light. I know apart from CEL the car will run fine without MAF connected, don't ask how...