Please list engines that are prone to piston/ring deposits, varnish, or sludge.

How many miles on the Outback before problems started? I have an 18 Legacy with the same engine that has had 6m/6k oil changes it's whole life minus a few 6m but much short mileage the first year or 2. By the time I started doing oil changes (the third one for the vehicle), I had 9,264 miles and the fourth OC was 12,234. Both those used M1 AFE. Since then, it has been Steady M1 EP and 6k changes. I'm at 74,019 now. The first 2 changes were done at the dealer and while I may have paper records, they aren't listed in my mysubaru account. I am planning on running VRP in it, but I have 2-3 more jugs of 1 EP that I want to get through before I do the 4 VRP as a possible preventative measure.
Are you burning oil yet?

Excellent plan to just run VRP. M1 EP staves off the oil burning longer but not forever. Learn from others!
 
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Got it. I remember this thread but forgot the details.
 
Are you burning oil yet?

Excellent plan to just run VRP. M1 EP staves off the oil burning longer but not forever. Learn from others!
I don't think so, but I'll have to pay more attention this next OCI which will be in December. If I remember, the last change using an extractor I closely filled up the 5qt jug. Maybe not full but pretty close. I think I am do for a real change too using the drain plug but getting under the car is hard at my house and December is usually pretty cold. Maybe in the spring, I'll do it at my fathers house or just pay some shop to change for me while supplying the oil and filter.

Like I said, I have 2-3 more jugs of M1. Without looking, I'm pretty sure they are the new Triple Action + formula whereas the others were not. Most of those 6k miles are highway. Don't know if that makes a difference.

One other note, usually I just use 5qts as opposed to the 5.1. The last change (maybe the last 2), I topped that last amount off with HPL Premium and will continue to do so until I switch.
 
You ran yours to what - 100K? Was it pretty sledged up? You were doing pretty short OCI as well due to the chain correct?
Gosh I hope mine was clean. From 20k to 103k (about 4yrs time) I never exceeded 3500mi between OCIs. I wish I had thought to pop a VVT solenoid out of the cam cover to check it for cleanliness before I got rid of it.

I base my statement on all the owners who went 5000-7500mi between OCIs, yet has sludge build up so bad, the recommended fix was "replace engine".
 
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Subaru non turbo EJ engines (ej251,252,253,259) all prone to oil control ring deposit related consumption after 100k

Already mentioned on list by OP the Subaru FB25 engine, can also add FB20 the 2.0L version of the FB25 2.5L.

There are many EZ series non turbo 6 cylinders with oil consumption from oil control ring deposits with high miles as well.

Heck, even engines known for not having oil consumption end up with oil consumption at even higher miles from oil control ring deposits, so is any engine really exempt from this list?
 
Gosh I hope mine was clean. From 20k to 103k (about 4yrs time) I never exceeded 3500mi between OCIs. I wish I had thought to pop a VVT solenoid out of the cam cover to check it for cleanliness before I got rid of it.

I base my statement on all the owners who went 5000-7500mi between OCIs, yet has sludge build up so bad, the recommended fix was "replace engine".
I would really like to know what causes sludge beyond outright abuse, because the MPI VK does not sludge but the GDI does, and the VQ line with MPI does not sludge but the new VQ35DD does. I don't think they really changed all that much structurally. I wonder if you ran really short OCI's like the old ones if they would do better.
 
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I would really like to know what causes sludge beyond outright abuse, because the MPI VK does not sludge but the GDI does, and the VQ line with MPI does not sludge but the new VQ35DD does. I don't think they really changed all that much structurally. I wonder if you ran really short OCI's like the old ones if they would do better.
I don't remember details but the old 1.8ts in the Audi's were notorious for sludge. SO much so they were blowing engines. They ended up changing the OCI from 10k to 5k, changed to a much larger filter and made synthetic oil mandatory, specifically meeting the VW 502.00/505.00 spec whereas I think conventional was the original recommendation. My guess is the small engine and the turbo had something major to do with it.

I have a S4 with the 2.7t and they recommended 10k changes also but I never did that. Always went with 5k.
 
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Define high miles. My 415,000 Xterra / VQ40 burns no oil.
I suppose an example would be the million mile 5.4L modular in the econoline. I believe the owners website was millionmilevan . org

The modular is not known for excessive oil consumption but with many more miles than average had oil consumption speculated from the rings
 
I suppose an example would be the million mile 5.4L modular in the econoline. I believe the owners website was millionmilevan . org

The modular is not known for excessive oil consumption but with many more miles than average had oil consumption speculated from the rings
No one can get to a million miles unless there commercial courier or something - its just a time thing. So if there always at operating temperature and constantly running, is it really a fair comparitor?

This Frontier went 1M without trouble. Same thing - courier duty. https://usa.nissannews.com/en-US/re...r-that-delivered-a-million-miles-and-counting
 
13' CRV with the K-24. Stuck rings around 300K with 3k OCI's. No sludge, but varnish. I attest this to alot of idling. Used car for work purposes covering sub-contractors. Alot of paperwork and computer work done in car. Basically, the car was my office desk. Cleared up with a piston soak a bit, then a few rounds of BG PN 109. Still running. No oil burning. Retired now, and the car is pretty much retired also.
 
No one can get to a million miles unless there commercial courier or something - its just a time thing. So if there always at operating temperature and constantly running, is it really a fair comparitor?

This Frontier went 1M without trouble. Same thing - courier duty. https://usa.nissannews.com/en-US/re...r-that-delivered-a-million-miles-and-counting
The point I'm making is that carbon in the rings was still an issue later in its (long) life, even if not an issue for normal ownership it was still eventually an issue
 
The point I'm making is that carbon in the rings was still an issue later in its (long) life, even if not an issue for normal ownership it was still eventually an issue
If your point was nothing lasts forever then I agree.

But my question was define high miles to which you indicated 1M miles. But if 99.9% of normal people could never get there even if they did keep the car forever, is it relevant. Wouldn't 1/2 million suffice? Or maybe 300K for most people?
 
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If your point was nothing lasts forever then I agree.

But my question was define high miles to which you indicated 1M miles. But if 99.9% of normal people could never get there even if they did keep the car forever, is it relevant. Wouldn't 1/2 million suffice? Or maybe 300K for most people?
My point is that piston ring carbon becomes an issue whether at a low or high amount of miles. Whether it is a well designed engine under ideal conditions reaching that consumption point at high miles, or a poor engine design in unfavorable conditions reaching that point at a low amount of miles.

High miles is a matter of perspective of useful life of engine.
If a Toyota 2AZ-FE engine has oil consumption at 600,000 miles, it would be considered acceptable because of high miles.
If a Toyota 2AZ-FE engine has oil consumption at 60,000 miles it would not be considered acceptable to many as it is not high miles.

If both engines consumed oil because of piston ring carbon, who is to say that 600,000 or 60,000 is high miles at all? Whether it is a courier car, uber, delivery vehicle or just Grandmas grocery getter the concept the remains the same so it is relevant to all engines and operators whether it is reached quickly or hardly ever. The entire understanding of high mileage may be changed.
 
I don't remember details but the old 1.8ts in the Audi's were notorious for sludge. SO much so they were blowing engines. They ended up changing the OCI from 10k to 5k, changed to a much larger filter and made synthetic oil mandatory, specifically meeting the VW 502.00/505.00 spec whereas I think conventional was the original recommendation. My guess is the small engine and the turbo had something major to do with it.

I have a S4 with the 2.7t and they recommended 10k changes also but I never did that. Always went with 5k.
Yes. In Europe, recommendations from the beginning were VW502.00.
In US at that time VW502.00 was really rare. So, they just recommended the API spec (I think it's API SJ). They sludge with any oil, conventional or synthetic if it was not VW 502.00 or some other Euro spec.
 
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