2007 Prius Piston Soak

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My '07 Prius has been consuming roughly 1 quart per ~1000 miles for the last 100k miles or so. I figured a piston soak was relatively low effort, low cost, and (hopefully) low risk. I've already replaced the PCV several times and run Castrol Edge high mileage on 5k OCIs. I removed the spark plugs and was greeted by this:

This was just after removing the plugs on a still warm engine. Tops of pistons 2/3 look pretty awful compared to 1/4 (to me anyhow).

I ended up going through two 12oz cans of Berryman's B12. I put a few ounces in each cylinder and rotated the crank by hand a few revolutions, poured a bit more, replaced spark plugs (loosely), and waited a few hours. Rinse, repeat until I was out of chemtool. Let it sit overnight and dumped the now pitch black oil and replaced with fresh. I also replaced the PCV and cleaned the MAF/throttle plate and whatever oil/etc. had accumulated beneath the throttle body in the intake plenum. Blew any remaining chemtool out of the cylinders, threw the old plugs back in, and started it up.

Billowed smoke for a few minutes but ran well otherwise. Drove it like a maniac for ~20 minutes, let the engine cool, and replaced the plugs with fresh ones. I accidentally deleted the "after" video I took, but all of the pistons looked like the top of #4. It certainly seems to run better, but I'll report back when I know more in regards to oil consumption.
 
Also, I was using NGK IFR5T11 (#4996) and the plugs were TRASHED. Perhaps 80,000 miles on them and the gap was well out of spec. I was pretty surprised considering the set prior to these had around 100k on them and looked nearly perfect.
 
"I ended up going through two 12oz cans of Berryman's B12"

According to Berrysmans site...

B-9 is now known as Professional Chem-Dip (part #0905), while B-12 Chemtool can be either our carburetor cleaner aerosol (parts #0117 and #0120) or a pourable fuel treatment (part #0116). In either case, B-12 Chemtool is not well-suited as a parts dip due to its fast evaporation rate and it's extreme flammability. If you have parts that require extended soak times, such as stuck piston rings or old metering blocks, then Chem-Dip is your best bet.

https://www.berrymanproducts.com/question/berryman-b12-verses-berryman-b9-carb-dip-cleaner/
 
I've done piston soaks on saturns, mostly stick shift ones, and know the runs-better feeling. The engine was directly connected to the wheels, underpowered, and I could feel the timing map where certain ranges were retarded.

A prius-- I have several now-- would be challenging to "feel" engine performance as it throttles up and down on its own whim, vaguely related to accellerator input. I bet they can get pretty sick, with the electric drive covering for it, before the owner takes action.

Hope all works out for the best!
 
How many total miles on the Prius; Mine was short tripped until 65K and I have to run 89 octane to prevent pinging after the engine is "hot to the core" (which in winter isn't too often)

I've been toying with adding Echo's Red Armor 2 stroke, which apparently is formulated to attack carbon deposits.

I'm not in oil burner mode but it is probably just a matter of time.
 
Originally Posted by krismoriah72
then Chem-Dip is your best bet.

https://www.berrymanproducts.com/question/berryman-b12-verses-berryman-b9-carb-dip-cleaner/

Yep, I realized my mistake once I'd started. The B12 does flash off VERY quickly, unfortunately. I considered fogging the intake with it but was too chicken to do so. Next time I have 2-3 days to experiment I'll try the B9.
Originally Posted by simple_gifts
How many total miles on the Prius

245,000 miles right now. It has rarely been short tripped -- every time it leaves the garage it gets driven at least 50 miles.
Originally Posted by eljefino
A prius-- I have several now-- would be challenging to "feel" engine performance

I can't say it feels any faster, but the engine doesn't seem to be revving as high when accelerating. Seems to make sense considering how the hybrid system works.
 
Originally Posted by Kira
Indeed. I didn't know one could drive a Prius like a maniac.

I do it occasionally - Uber drivers do it all the time.

FWIW, Prii don't handle too horribly but then again you can only do so much with 185/65-15 or 195/65-15 tires with a solid rear axle. The 4th gen cars on the new Toyota platform with 4-wheel independent suspension feel better.
 
I used BG EPR and Liqui Moly Engine Oil Cleaner to get my consumption down, my car was a family hand-me-down that I did all the maintenance on. I was able to get the consumption down from 1qt/2000mi to 1qt/3000mi.

This weekend, I went over to The Critic's shop and I did an OCI with Valvoline Premium Blue Restore and a Fram Ultra. Let's see if that cleans up the ring packs and oil return holes. I kinda want to pull the engine out and do a re-ring but I gotta wait until I have a 2nd car and time on my hands.

My suspicion of why Prii drink oil is low tension rings + being a hybrid, the engine doesn't get a proper break in as you can't really get to redline nor vary the engine speeds under load. Corollas also drink oil - again low tension rings. Toyotas seem to be hard on their oil, yet their V6/V8s and I6s aren't known to drink oil. I had an 1991 LS400 that would occasionally drink but it had 297K when I got rid of it and the Sienna my parents have doesn't drink at all.
 
I did something similar to our old '06 Prius that began burning oil, only I used Kroil and put some in the tank as well. I did switch to Valvoline HM in a 5w/30 afterward and it slowed/stopped the burning until will got rid of it 20k later. I don't know if it was the Kroil or the Valvoline or the combo, but it worked for me so I didn't question it.

Good luck to you!
 
Originally Posted by WylieCoyote
You think fuel brand / grade had an impact on this?


I've always used regular and have paid little mind to brand.

I do wonder if fuel injectors could have something to do with it, though.
 
Originally Posted by nthach

My suspicion of why Prii drink oil is low tension rings + being a hybrid, the engine doesn't get a proper break in as you can't really get to redline nor vary the engine speeds under load.


It's also hard to put a real good vacuum on the engine, like by downshifting for engine braking. IDK what effect "B" has, but doubt it's much use.

When I floor the pedal, Torque reports a throttle position of 60-something percent. Sorta wonder what's up with that, too.
 
Originally Posted by InhalingBullets
I did something similar to our old '06 Prius that began burning oil, only I used Kroil and put some in the tank as well. I did switch to Valvoline HM in a 5w/30 afterward and it slowed/stopped the burning until will got rid of it 20k later. I don't know if it was the Kroil or the Valvoline or the combo, but it worked for me so I didn't question it.

Good luck to you!

You used a bottle of Kroil in the oil cap, like someone would use Rislone? If not a bottle, then how much?
How many quarts does that 06' Prius take?
 
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Originally Posted by krismoriah72
"I ended up going through two 12oz cans of Berryman's B12"

According to Berrysmans site...

B-9 is now known as Professional Chem-Dip (part #0905), while B-12 Chemtool can be either our carburetor cleaner aerosol (parts #0117 and #0120) or a pourable fuel treatment (part #0116). In either case, B-12 Chemtool is not well-suited as a parts dip due to its fast evaporation rate and it's extreme flammability. If you have parts that require extended soak times, such as stuck piston rings or old metering blocks, then Chem-Dip is your best bet.

https://www.berrymanproducts.com/question/berryman-b12-verses-berryman-b9-carb-dip-cleaner/

Berrymans just wants to sell you the more expensive Chem-Dip. I'm sure it's a good product but I've used B12 as a soak for probably close to 30yrs now, long before the Chem-Dip product came about and it always does a good job. Just pour it in, stuff a shop rag down the bore and let it do it's job overnight then drain the oil the next day. Easy peasy, lemon squeezy.

*Never had a problem igniting, then again i don't smoke and the spark plugs are removed on a cold engine..so I don't see how it'd ignite. I've also used Motor Medic as a soak, check out the SDS.. it's basically all solvents with a light oil (kerosene maybe??) as a carrier. That's pretty much what MMO is, kerosene and Stoddard solvent. Remember, like dissolves like....
 
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Originally Posted by eljefino
Originally Posted by nthach
My suspicion of why Prii drink oil is low tension rings + being a hybrid, the engine doesn't get a proper break in as you can't really get to redline nor vary the engine speeds under load.
It's also hard to put a real good vacuum on the engine, like by downshifting for engine braking. IDK what effect "B" has, but doubt it's much use.
When I floor the pedal, Torque reports a throttle position of 60-something percent. Sorta wonder what's up with that, too.
?? Varying the engine speed is as easy as varying the accelerator position. The typical break-in suggestion of varying the load at constant engine speed, would be more difficult, because the system tries to maintain relatively constant load.

Vacuum is fairly high (i.e., low MAP) when it's idling. MAP usually holds around 12 psi when it's working, except at extremes. I haven't checked what MAP is while using "B" for engine braking down a hill; that might be interesting.
 
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