How much of your favorite cleaning liquid to use in a piston soak, and why? (valve, engine)

[M3 Mitch]

I'm not sure doing this will help the "curb appeal" of a car much, if you are just wanting to clean it up and "flip" it.



On a car like this, maybe a set of spark plugs, maybe an O2 sensor, make sure it's not throwing any codes, if it runs smooth with reasonable power, that's all you can expect and all any real buyer will expect. Mostly clean it up, if the paint is good, maybe wax it. Get all the glass really clean, I personally like Stoner Invisible Glass, both the spray and the towelettes. Make it smell good.



I personally refuse to obsess about putting on new wear items, which is almost always done on the cheap. A set of new cheap tires and a chain garage brake "overhaul" do more to make me suspicious than they would help sell me the car. So long as tires and brakes have some life left in them, I would sell it as is, price it accordingly, and let the new owner decide what he or she wants to do about these wear items. Tires worn about halfway down and all are uniform means to me that the suspension and alignment at least nominally "work". Brand new cheap tires makes me think the tires that came off had odd wear patterns from suspension problems. Likewise engine oil. Brand new oil with less than 100 miles on it just makes me think you are trying to hide something.

[Quietude]

Originally Posted by lollydoodoo

Please forgive me, I do try to ask general questions. I do a car almost every month and I do my best to clean up other people's formerly neglected wrecks etc into some semblance of a great car, possibly re-sell I try to ask general questions. In this case it's a 1989 Nissan Sentra with 258k miles and yes I want to know if the liquids on a hot engine does anything. So many swear it does.

Are you talking about internal or external cleaning, here?

An engine would have to be in terrible shape to need the cylinders and pistons cleaned... and the cleaning would be only a temporary fix.

[lollydoodoo]

Can it hurt anything?

[Quietude]

Pouring non- or semi-flammable liquid into cylinders isn't a completely great idea. Enough, and a compression stroke could blow the head gasket or even damage the rings.

[M3 Mitch]

I guess it's possible if the ring pack is really dirty, from short trips and few oil changes, that putting Sea Foam or similar solvents into spark plug holes to soak out some of the crud, to loosen it so it can be blown out into the oil - might possibly raise compression and/or reduce oil burning. Particularly in an I-4 with the pistons moving more or less vertical, in a V engine, the solvent would only go into the "downhill" side of the piston and not clean all around, or not as well.


That said, I would just use some patience, and better oil changed more often, maybe some Techron in the gas. Like I said in my last post.



Why do you think this engine is dirty enough to benefit from a specific cleaning like this?

[lollydoodoo]

Originally Posted by M3 Mitch

I guess it's possible if the ring pack is really dirty, from short trips and few oil changes, that putting Sea Foam or similar solvents into spark plug holes to soak out some of the crud, to loosen it so it can be blown out into the oil - might possibly raise compression and/or reduce oil burning. Particularly in an I-4 with the pistons moving more or less vertical, in a V engine, the solvent would only go into the "downhill" side of the piston and not clean all around, or not as well.


That said, I would just use some patience, and better oil changed more often, maybe some Techron in the gas. Like I said in my last post.



Why do you think this engine is dirty enough to benefit from a specific cleaning like this?

You see, M3 Mitch, I have become somewhat of a believer in noticing more smoothness and throttle response after using specifically Seafoam sometimes after a water clean (done carefully, seafoam absorbs water) and things like this. Had some GM cars which taught me all about how carbon can be issue. I then learned that pretty much any engine that isn't super duper super clean can benefit, so now i want to fact check myself.

Every forum. And I do mean every forum. Of car discussion. This topic when it comes up, you get about 80% of people they say Yeah Seafoam cleans it up then 10% say the Smoke Show is just the Seafoam and doesn't do anything. In the gas I agree, its a waste unless maybe you have water in there or need a slight octane boost like for a turbo. But. Every discussion i see talks about through either the intake or the brake booster. Even water right at the throttle plate works too. No discussion is ever really had about this piston soak business.

You at least are smart enough to acknowledge that this would be iffy on a V engine, and impossible on a Porsche or Subaru Boxer Engine. So I am liking your insight.

Seafoam is combustible, the car wants to run off it if you use a lot. The questions I have are specific to soaking pistons.

Hot engine supposed to be better than cold, though if it sits then what is difference

Some people let it sit 15 minutes, during course of spark plug changes which really doesn't even take 15 minutes

Some a half hour
Some an hour
Some an hour and a half
Some 6 hours
Some 8 hours
Some overnight
Some a day
Some a week
Some a month
Or as long as their car sits. Unused

Seafoam isn't the only one out there. People like to say how Seafoam is just this and just that.. yeah but if it cleans even paint brushes then. That carbon on the top of the piston. It is odd how more carbon technically is supposed to raise a compression ratio, but blasting it off and getting it small and hot enough to get out the exhaust and not clog (heat and being able to mash past substrate will get it out with exhaust force, mostly heat making it melt and goo) will make an engine run so smooth.

So this thread I seek to address specifically the piston apication.

Now, filling a cylinder all the way up, putting a spark plug in then turning it. That may not be a good move. But 1 or 2 ounces? Hey, if the piston is traveling up then its going out an exhaust valve and if it is going down then its getting into oil ring etc so I dont see how it can blow something out unless it is not compressible like water and all the way full..

I cannot through the spark plug hole and see black on the pistons and while I realize they will perhaps never be clean, this goes back to the carbon, compression ratio vs smoothness paradox.

[lollydoodoo]

https://youtu.be/CgmzTAgooD8

[Quietude]

To be honest, this all strikes me as voodoo or cargo cult mechanicking.

[phinneas j. whoopee]

Its all speculation without a borescope inspection. This is rather lengthy, its from an Isuzu forum where I posted it 6 years ago.

Okay I'd like to share my little adventure trying to pass smog on an unmodified 170k mile 95 passport V6. Failed for hi NOS on the 25 mph run. Had some iffy vacuum lines and a couple exhaust leaks but they shouldn't have been enough to fail it. The carbon buildup issue seemed like a logical villain so I got my hands on a real optical flexible borescope and took a look inside a couple of cylinders (through the spark plug holes) and good gawd what a mess in all of them, to various degrees. They all looked like the surface of the moon, some you couldn't see any of the piston top metal. I'd say about 1/8- 3/16 thick in some spots.
So I am seeing all the glowing reviews about SEAFOAM and how I'm just a big white cloud away from a clean engine.
I do it by the book and get a somewhat lesser white cloud than some but a cloud nonetheless. I used half a can and poured the other half in the tank. After I drove that away I looked in the borescope again.
Not only is the carbon still there it may have gotten worse.
So I go buy that "pass or double your money back" stuff and pour that in the tank, then drive it away.
The carbon. It laughs at me. It mocks me.
So I go buy some Chevron Techron. Drive a bottle of that away.
The carbon remains, I swear I hear it making jokes about my family.
Now I tried that Seafoam, and PODMB and Techron based upon the reviews of all the fanboys who swore it worked.
Yet I'm noticing in the hundreds of threads I had now pored over online a common theme. Not one endorser of Seafoam or any similar chemical had arrived at their findings (swearing it worked for them) with any objective reasoning- they simply looked at a white cloud, thought the engine ran better, and put their seal of approval on it. Nothing as tangible as looking at the combustion chambers before and after.
Would thick carbon deposits instantly burn off into thick white clouds? I don't know but it appears Seafoam does burn off in a white cloud. All my (dried) carbon deposits remained. It may have dissolved some of the wet "sludge" deposits pre-combustion chamber. Then put them on the piston maybe.
In any case those 3 popular chemicals had virtually no visible effect on the thick piston top carbon deposits.

These carbon deposits would wreak havoc on the operation of an engine in the right circumstances. Raising the compression ratio. Interfering with fuel air mixture flow. It's weight on top of the pistons, causing imbalance to the rotating mass. Worst is that in the warmest operating environment the carbon will glow and intermittently preignite the air fuel charge out of time with the power stroke, robbing the engine of power and economy.
Not in my engine!

Looking for a solution I went to Harbor Freight and bought a pack of long wire brushes, thinking I could mechanically scrape off the carbon then vacuum it out with a shop vac. Poking a rod into the top of a piston the stuff would budge but all advice I found online said don't do it, you'll get carbon in the rings and ruin your engine. Okay. So what to do?

"My dad knew a guy whose brother's cousin's sister heard of a guy who...... squirted water down the carb/flew planes in WW2/ had a turbo powered lawn mower with WATER INJECTION!"

So I tried dumping a few tablespoons in the same way I introduced the seafoam- which was a T in the PCV vacuum line. Didn't seem to do much HOWEVER I persevered. Picked up a bunch of parts from around my workshop and home depot and came up with a way to fairly precisely meter a water mixture into the engine while I drove. After some tinkering with the technique I do have to declare this is the only way to get years worth of carbon bull huckey out of an engine. It takes a week or two and let me warn you

If you are not very careful and do this stupidly dumping water into a running engine in the wrong amount or the wrong conditions will ruin your engine in seconds. Hydrolock for starters but there are other dangers. However looking in my engine with a borescope made me a believer. And my passport runs like a new truck.

It idles smoother, revs up like lightning and wants to bolt up near redline like I never knew. I'm going to do my smog retest tomorrow which of course is the ultimate goal but I see shiny new piston tops in my engine now.

You simply hook up a very small pvc hose, like 1/16 ID is ideal (the one I used came from an airbrush kit) from inside the vehicle through the firewall to a T on the PCV valve vacuum line. You want a tiny hose, it's a safeguard against a mistake like cracking the valve open too far and introducing too much water at once. Inside the vehicle you'll need a water supply container you can monitor the overall use from (I'm using a 24 oz smart water bottle) and hopefully mount it so it stays upright. You'll need a feed tube inside that bottle, again very small is good to limit the flow. You'll need a pinhole in that bottle's cap to relieve pressure as it drains. (ideally 13 oz of water in 15 miles at freeway speeds- you're shooting for 10:1 fuel to water)
Next and this is important as I didn't do it at first but it seems critical for atomizing AND safety for clearing the tube before shut down, you need two 1/4" brass needle valves, Home Depot has them for about $6 each. One controls the water flow, and right after the water enters the tube we want a way to introduce air (vacuum) into the tube. It's important to clear all the water out of the tube before you shut down the engine because you DO NOT want water injection into a cold engine. You DO NOT want water injection into an idling engine at any temperature. You DO want to inject water at a 10:1 fuel/water ratio into a HOT engine under some kind of load and the chemical reaction of the water burning will cause the carbon to be harmlessly blasted out of your engine. Ideally this works best when travelling down a highway at a constant speed and RPM simply because you can dial in a steady flow and see what you're using. You'll have a pair of valves next to you but you don't need to be terribly anal about it. Distilled water will obviously be better.

There is no apparent performance benefit by simply injecting water into our engines unless you have a boosted engine and if you do you aren't reading this you know more about this stuff than I do so go drink a beer and think of anything I'm screwing up with here.

What we're doing is cleaning the engine, that's all. I'm going to keep this all hooked up and about once a month run about 13 oz of water into it over about 15 miles and that should keep her good to go- for about $20 in parts I think this is the best money I have ever spent on a car. You may be reading this and thinking "why the **** do I want to dick around with this stuff on my truck which I guess runs okay?" well do you know what the inside of your combustion chambers look like? How neglected they have become? If you did and saw what I saw you would feel like a jerk just starting it up.

Seafoam may have some benefits. I declare removing hardened carbon deposits from combustion chambers was never one and people have been falling for this "white cloud" nonsense by the millions for years. If you didn't look down a borescope and see the tops of your pistons before and after what you did it's all just useless speculation- faith and belief in some person's endorsement, that some day the problem might go away if you did what they did. That's not proper troubleshooting. Thick, hard carbon deposits on piston faces to this degree is a real mechanical problem just like a broken timing belt you have to verify works or it doesn't. If the deposits are not removed the truck generates NOS and you don't get tags and the truck gets towed.

[M3 Mitch]

Water will remove carbon. Water injection was used in some WWII fighter planes. You do have to know what you are doing, a mist of water is what you want, not a stream.