Cleaning carbon deposits

MMO will THIN your oil.

If you are having a problem with burning oil because of worn rings or leaking gaskets,
it will likely make it WORSE and not better.

And as for removing carbon deposits from your plugs............I'm skeptical.
If you had the plugs out and knew that they were fouled with carbon, you should not
have put them back in the first place.

 

Valves out of adjustment will not give you a loud knock. You either have a worn out engine with excessive bearing clearance or carboned up pistons with a carbon knock. If you are serious about cleaning pistons/combustion chambers, you need piston soak or slow water ingestion. Techron should be also your friend.

 

If the engine consumes oil, that results in carbon. So, it's quite likely. That would rob you of power by retarded ignition.

 

Here's my problem with that:
No need to re-invent the wheel. That has already been done, a thousand times or more.

The results are: In and old engine that has lots of miles that starts making noise and using oil......you need to use THICKER oil not thinner.
In recent years, advances have been made with "seal wetter" too.
In case the problem is mostly valve guide seals instead of worn rings, my advice is to start using 10W40 "high mileage" oil and quit screwing around with it beyond that.

Your MMO thinning out the oil will certainly make matters worse, not better.

 

I don't see much difference compared to regular Otto cycle ICE. You turn it first with plugs out. If you are concerned, evacuate liquid first (if any left) with piece tube and large syringe before turning ICE.
Now, for carbon removal, I had better yield with Berryman's B12 than MMO. You can do both sequentially, too. B12 followed by MMO, each several hours or overnight. I did that in Corolla and that completely stopped oil consumption for 5000 miles and only later consumption came back but to a lesser degree.

 

I don't see much difference compared to regular Otto cycle ICE. You turn it first with plugs out. If you are concerned, evacuate liquid first (if any left) with piece of tube and large syringe before turning ICE.
Now, for carbon removal, I had better yield with Berryman's B12 than MMO. You can do both sequentially, too. B12 followed by MMO, each several hours or overnight. I did that in Corolla and that completely stopped oil consumption for 5000 miles and only later consumption came back but to a much lesser degree (so much for the naysayers above who have no clue whatsoever). BTW, aggressive piston soaks should be done right before oil/filter change.

 

Given those results, have you considered that what you accomplished really was freeing up a stuck ring or two.......and it really had nothing to do with "carbon buildup" at all ??

Despite all the hype from people selling products to eliminate "damaging" carbon buildup in engines, except in rare and unusual circumstances, where there really is another underlying condition that needs to be fixed anyway, there is some normal accumulation of carbon inside the combustion chambers of almost EVERY engine and it causes no problem whatsoever, partly because it is self-limiting. That is, after the accumulation reaches a certain point, it either falls off or burns off.

If you really have excessive carbon buildup on the plugs or valves or pistons, you need to find out WHY and fix that. Simply getting rid of the carbon itself accomplishes pretty much nothing and is a waste of time and money.

 

Only to repeat what I already said;
THICKER oil, not thinner. 10W40 or 20W50 "High Mileage" type.

And that knock is probably a loose bearing, on the crank or piston pin......and the old girl probably won't last much longer no matter what you do.

If you plan on trading in your old engine for a rebuilt one, your old engine might be worth quite a bit MORE with just a knock instead of with a hole in the block from connecting rods flying around loose inside.

Certain basics apply to pretty much all engines.
LOUD knocks usually don't last too long, as the engine usually stops making ANY sounds fairly soon.

 

Assuming your $400 figure is right.......one with ANY know major defect probably isn't worth much more than melt down value. I find $400 to be rather amazing; would think it would vary quite a bit by the mileage at the time of the wreck.

 

Which shows you there is very little demand for a used engine. The Prius gasoline engine is highly reliable, if you keep the engine oil/oil filter changed per the maintenance schedule and keep an eye on the engine oil level between changes, the engine should normally last for "the life of the vehicle" no matter how you define that term.

I've noticed only a couple of situations where the engine had to be replaced, and it seemed that poor or no maintenance (or hitting the engine oil pan on a road obstacle, causing the oil to quickly leak out) were the reasons for that.

 

This guy had prius engine knock, thought it was shot bearings, but he was wrong. Fixed by cleaning and new rings:

 

Which proves what exactly ?? That things can fail.....like worn rings....that make carbon buildup a real problem ?
No argument there.

Given that situation, however, none of the "magic snake oil" fixes for carbon buildup would have done any good at all.
Well, not for more than a few miles anyway.

If you REALLY have a bad carbon buildup problem, you need to find the REASON and fix it.
Just treating the "symptom" won't accomplish anything useful.

 

You either have a comprehension problem or just argue for the sake of arguing. Not sure which.
Lets see if this is simple enough for you (in a good faith effort):
Gummed rings -> oil consumption -> carboned combustion chambers -> carbon knock (and more gummed rings, vicious cycle starts).
Piston soaks -> cleaning rings and pistons -> less oil consumption -> less problems and a chance to break the vicious cycle.