Your Thoughts about a Piston Soak and Diesel Oil in Corolla?

[giantsforever]

2006 Corolla with stock 1ZZ-FE engine, 141k miles, and unknown maintenance history. Oil cap calls for 5W-30 SL. I've had it less than 1,000 miles. Piston crowns are black and only on spark plug #4 is black residue (didn't think to take a photo before cleaning it). No pinging or check engine light. Accelerates okay.

Is it wise to clean those piston tops with a piston soak? What would you recommend soaking it with?

How about using synthetic diesel motor oil, eg Chevron Delo fully synthetic 400 XSP CK-4/SN 5W-40, to clean engine internals?

Thanks

 

[javacontour]

Leave it alone and drive it. See if it consumes oil. Choose what you want to use for your next oil change based on what it does over the next 2-4k miles.

I'd just use a good quality 5W30 and drive the car.

 

[giantsforever]

Thank you.

Can you recommend any good 5W30 synthetic oils for this car?

 

[skyactiv]

https://www.amazon.com/Genuine-1052626-Engine-Carburetor-Cleaner/dp/B000QII698

 

[Kansas_Ron]

I have had better results with a 10W30, yours may vary. With the miles on it you will have a clogged cat nearing 190,000-200,000 miles and don't forget the O2 sensors. Just drive it and monitor it and keep it topped off.

 

[JohnG]

You've cleaned the top of the piston, good. The real problem may be stuck rings on the cylinder. There were some really poor VII's back then that may have caused this issue. I don't know if it's a huge problem at this point, but I understand you wanting to have the engine in perfect shape.
GM made a very good soaking solution at one point for carbonized rings. I don't really think any of motor oil is going to do the job. I think it would need to be more of a solvent based solution.
I'd also make sure that the carbon was NOT coming from a rich fuel mixture in that cylinder.

 

[giantsforever]

Thanks.

JohnG, what are VIIs?

 

[Imp4]

Don't do anything to it.....yet (except maybe the plugs if they appear to be original).

The thing is, you're likely looking at 141,000 miles worth of accumulation on those piston crowns. And quite possibly original spark plugs. So it might not be a big deal at all assuming the plugs have been cleaned as you described or changed out for a fresh set.

If it drives well, gets decent mileage, check engine light is off and it doesn't consume an appreciable amount of oil, then just drive it.

You wont know if it consumes oil until you have 2k-3k+ miles on it. So just drive it for a while and monitor performance. It's quite likely that all it needs is gasoline and a regular preventative maintenance schedule.

 

[simple_gifts]

IIRC it seems the 1zz-fe burning issue was not a prevalent from 2005-7; my friend has a vibe with 160K and there is no wild consumption; i would leave it alone or use some redline or amsoil fuel system cleaner.

 

[JohnG]

VII's are viscosity index improvers. Likely are being called something different these days, like VI's or something. Older oils, like SL/non synthetics had improvers that would "coke" or burn in the ring pack forming carbon and preventing them from moving correctly.

The Northstar engine had rings very near the top of the piston, so they were subject to a lot more heat than normal. Everything was fine, except the engine oil was not up to that job back then. Today, those improvers are much better at withstanding higher temps. Unfortunately, just putting in "newer" oil will not unstick a ring pack if it is carboned up. GM made a solvent to do this job, and it worked pretty well I understand.

This is all dependent on what has caused your carbon buildup on the piston crown of course. It could be fuel for all I know.

 

[Powerglide]

You guys speak of 2006 as if it was 1976. The oils that went into that motor were more than adequate and perfectly capable of preventing the "coking" you're referring to. It's the lack of proper OCIs that caused whatever deposits may have accumulated on the Pistons, the ring packs, and the combustion chamber.

 

[jqgz]

Pull plugs, spray in an ounce of Kreen into each cylinder, and turn engine over by hand a few times to work it into the rings a bit. Allow to evaporate be careful not to hydrolock it. Then, put a bit of kreen in the oil and the gas.

 

[CharBaby]

Originally Posted by javacontour
Leave it alone and drive it. See if it consumes oil. Choose what you want to use for your next oil change based on what it does over the next 2-4k miles.

I'd just use a good quality 5W30 and drive the car.



^^^This!

 

[dave1251]

Originally Posted by Powerglide
You guys speak of 2006 as if it was 1976. The oils that went into that motor were more than adequate and perfectly capable of preventing the "coking" you're referring to. It's the lack of proper OCIs that caused whatever deposits may have accumulated on the Pistons, the ring packs, and the combustion chamber.



Great post! I believe you are hitting the bullseye.

 

[Rob_Roy]

If the engine appear to operate normally, there is no need to do abnormal maintenance. A tank or two of gas treated with your favorite injector cleaner certainly won't hurt, and a set of plugs if they are due.

 

[giantsforever]

Thanks.

The car came with iridium spark plugs, which Toyota says last 120k miles. Gap on them is fine, no unusual blemishes, except for #4 with dark debris. Nothing unusual in terms of performance except rough idle, which I have narrowed down to engine mounts (idle speed is normal at around 800 rpm).

When should I change those spark plugs?

 

[kschachn]

Originally Posted by giantsforever
Thanks.

The car came with iridium spark plugs, which Toyota says last 120k miles. Gap on them is fine, no unusual blemishes, except for #4 with dark debris. Nothing unusual in terms of performance except rough idle, which I have narrowed down to engine mounts (idle speed is normal at around 800 rpm).

When should I change those spark plugs?

How about 120K miles?

 

[TurboTravis]

Originally Posted by Char Baby
Originally Posted by javacontour
Leave it alone and drive it. See if it consumes oil. Choose what you want to use for your next oil change based on what it does over the next 2-4k miles.

I'd just use a good quality 5W30 and drive the car.



^^^This!


100%.

 

[nicholas]

Try BG EPR it worked wonders in an audi that had bad oil control rings.

Harsh stuff though. But it helped.

 

[Graham Piccinini]

I had a couple vehicles with 1ZZ engine. One of them was a 2006 Pontiac Vibe with AWD. On my first drive home with it it burned a quart of oil in 100 miles. Added some MMO to it, then a few short OCIs with Diesel Delo 5w40 (which is also SN rated) and some other oils got the consumption decreased to 1qt per 5k miles. But engine still had tons of crusty sludge, so I sold it pretty quick as it started having other issues.