Piston Soak for reducing oil consumption

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Hi everyone, I have a 285k miles 01 Corolla with a 7AFE engine that is consuming oil. At the 250k miles the engine has overhauled with new piston & rings, bearings, gasket and seals but the block wasn´t bored in a machine shop because it looked in good shape, it didn´t had any ridge in the top part of the cylinders. At 273k miles the engine overheated because of a faulty radiator cap, it bent the cylinder head and whe had to send it to a machine shop so it would be flat, we changed all the gasket of the cylinder head including the valve stem seals.

The engine has always used 20w50 oil and it consumed 0.8 qts every 1k miles, then I began to read in this forum that thick motor oil isn´t always the best so I decided to give HDEO 15w40 a try and now the engine is consuming 1.1 qts every 1k miles. I´m planning to do 1 more oil change using an HDEO 15w40 to see if the extra detergents help clean the engine (which isn´t very dirty by the way, but cleaner is always better) and then I want to try the old 20w50 again to see if it lowers the oil consumption.

What I wanted to know is if you think that a piston soak could help me to reduce the oil consumption rate? What I think is that the new rings have only 2-3 years and 35k miles, my guess is that they aren´t stuck, I think that the real problem is that they lost flexibility in the last overheat which happened at 273k miles. Would a piston soak help me?

The valve seals have only 12k miles and I dont see any signs of worn valve seals, the PCV valve was checked in less than 3k miles ago and it wasn´t blocked and it sounded like it should when I shaked it, I could even blow with my mouth and it let the airflow go to one side and it caused a restriction sucking (just like it should, because it is like a check valve). I also cleaned it.

What products would you recommend to do a piston soak? I´m in Venezuela so the products that you might use aren´t avaible here, what I have in mind to use is:

- Injector Cleaner
- Kerosene
- Diesel
- Carburetor Cleaner
- Acetone
- ATF
- Engine Flush for oil

I recently took the spark plugs out to see the piston tops and they look very shiny, they have just little pieces of carbon in them, I think is because they are only 35k miles old.
 
Any Berryman B-12 Chemtool available? That would do it. Otherwise, a combination of acetone and carburetor cleaner would do it too--IF the rings are sticking or stuck.
 
Could my PCV Valve be worn even if its sealing the air flow from the intake manifold to the crankcase but it is letting the air flow pass from the crankcase to the intake manifold? It´s also making a clicking noise when I shake it. Can it be worn even this conditions?

It´s a metalic one, but I must have a lot of thousands of miles.
 
You say it was not bored in a machine shop, because it looked good. Does that mean a machine shop checked it, or it looked good and you did not take it in?

If the bores are not round anymore, or the hone finish is not correct for the ring type( cast, moly etc) that could be the problem. Its possible that the overheat scored the cylinders as well.

If i was going to do a piston soak, I use a strong solvent like Berryman b-12. I'd want some oil in there too. The solvents could wash all the oil off the rings and cylinder causing wear.
 
If the problem isn't the pcv valve then my guess is going to be the block not the rings.
 
Thanks for your answer.

Originally Posted By: 2015_PSD
Any Berryman B-12 Chemtool available?
No, it isn´t but I will try to find an equivalent product.


Originally Posted By: 2015_PSD
a combination of acetone and carburetor cleaner would do it too
Do you think is safe for the block and piston to use that?

Originally Posted By: 2015_PSD
IF the rings are sticking or stuck.
How can I know if they are sticking or stuck?
 
Originally Posted By: Emanuel
Thanks for your answer.

Originally Posted By: 2015_PSD
Any Berryman B-12 Chemtool available?
No, it isn´t but I will try to find an equivalent product.


Originally Posted By: 2015_PSD
a combination of acetone and carburetor cleaner would do it too
Do you think is safe for the block and piston to use that?

Originally Posted By: 2015_PSD
IF the rings are sticking or stuck.
How can I know if they are sticking or stuck?


Berrymans is a mix of 80-90% acetone and 10% toluene, maybe you can get those and make a mix.
 
Last edited:
Originally Posted By: spasm3
If the bores are not round anymore, or the hone finish is not correct for the ring type( cast, moly etc) that could be the problem. Its possible that the overheat scored the cylinders as well.
I think that not round cylinders can be the real problem, I don´t think the overheat scored the cylinders.[/quote]

Originally Posted By: spasm3
If i was going to do a piston soak, I use a strong solvent like Berryman b-12. I'd want some oil in there too. The solvents could wash all the oil off the rings and cylinder causing wear.
Couldn´t I add motor oil after the treatment? Or should I add oil with the treatment?
 
Originally Posted By: Emanuel
Originally Posted By: spasm3
If the bores are not round anymore, or the hone finish is not correct for the ring type( cast, moly etc) that could be the problem. Its possible that the overheat scored the cylinders as well.
I think that not round cylinders can be the real problem, I don´t think the overheat scored the cylinders.


Originally Posted By: spasm3
If i was going to do a piston soak, I use a strong solvent like Berryman b-12. I'd want some oil in there too. The solvents could wash all the oil off the rings and cylinder causing wear.
Couldn´t I add motor oil after the treatment? Or should I add oil with the treatment? [/quote]

I mean adding oil to the cylinders after the solvent dries up
 
Originally Posted By: Emanuel


Originally Posted By: spasm3
If i was going to do a piston soak, I use a strong solvent like Berryman b-12. I'd want some oil in there too. The solvents could wash all the oil off the rings and cylinder causing wear.
Couldn´t I add motor oil after the treatment? Or should I add oil with the treatment?


If you are going to spin the engine over some with the solvent in there, add it after the solvent but before spinning the pistons up and down.

If you are not going to spin the engine with the solvent. Add the solvent, let it sit then add oil before putting the plugs back in and firing it up.
 
I wouldn't think a recently overhauled engine would need a piston soak.What is the compression like? Just keep on top of the oil loss. I learned to carry a few qts in the trunk. I would start using 20w50 oil and check the stick frequently. Thats how it used to be. Fill it up and check the oil.
 
Stuck rings doesn't sound especially likely in this case.

If I thought I had stuck rings, I'd do a soak with DOT3 brake fluid, then I'd follow that up with a water treatment. Alternate that a few times and then change the oil (probably for the thicker stuff.)

My cars starting to run on a bit after switching off, so I'll do a water treatment fairly soon. Probably won't do a brake fluid soak because I don't especially suspect stuck rings and I don't want to change the oil yet.
 
Does the car smoke out the exhaust? If so, see if it does it on acceleration, overrun, or start up. I’m thinking it’s smoking on acceleration. How hot did it get when it was overheated? Possible rings lost their temper or out of round cylinders.
Thanks,
Andy
 
In Venezuela you could probably run a straight weight oil which MIGHT cut consumption a bit and would reduce the chance of ring sticking, IF that is likely to be an issue.
 
Originally Posted By: CT8
The engine is worn , what is the engines compression?


I don't know the compression but I would say it has plenty of power, I drove it at 102 mph recently
 
Originally Posted By: AndyB
Does the car smoke out the exhaust? If so, see if it does it on acceleration, overrun, or start up. I’m thinking it’s smoking on acceleration. How hot did it get when it was overheated? Possible rings lost their temper or out of round cylinders.
Thanks,
Andy

I have pushed the engine at 4000 rpm in a uphill in 3rd gear and I didn't see any smoke looking by the mirrors. It doesn't smokes at that rpm going downhill with the throttle closed and doesn't smoke neither in the mornings, it never smokes oil just moisture in the morning and sometimes it doesn't even smoke moisture.

It overheated pretty bad, enough to bend the combustion chamber.
 
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