Oil for higher mileage N/A subaru 2.5l

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Alright I have a 2006 Impreza 2.5i its a higher mileage vehilce at 238 Km. I just resealed the engine completely and after eliminating all leaks have found its consuming about a liter every 1250-1500km. I want to play with oils to see if i can reduce that hopefully to zero but any improvement is welcome. Currently Im using castrol GTX 5w-30 and blue Subaru OEM honeywell filter

My thoughts are

-try to clean up and release the ring pack, with a HDEO or pennzoil yellow bottle, i do realize this could increase consumption.

-Just play with brands and weights see if i can reduce it that way, any and all suggestions would be welcome

with the turbo crowd WRX / STI's i have heard nothing but good things about Rotella 5w-40 syn. Not sure if it is a good option for the N/A 2.5I I figure it may be too heavy or just overkill
 
First off, did you replace PCV? Are your spark plugs according to spec? It seems you're on the right track using dino oil during the break in period. If it still consumes oil afterwards, going with 40 weight might lessen it. You can go full synthetic with T6 after break in.
 
I have a 2000 RS and my wife used to have a 99 Outback and both cars never used more than a quart between the two of them with MaxLife or Pennzoil Conventional High Mileage. IMO, try a robust 30 grade for a couple of OCI's before jumping to a 40 grade. Yes, and replace the PCV if you haven't.

-Dennis
 
I have only been unable to find a few cases with real data for cleanups using motor oil. Real data like independent teardowns before and after with different oils are hard to find. Just claims by the manufacturers and the users. I have been reading along on multiple forums looking for this, sorted out those who claim something with no proof other than what others say or never used the product from those that attempted to prove a cleaning claim. Here's a small summary:

Read a lot of threads about subie turbo enthusiasts using T6. They claim the oil holds up better, makes the engine quieter. Some on here claim a HDEO cleans better, some posts here claim disappointment. More claim oil consumption stayed the same than improved. those that used the thicker t5's claimed an improvement in consumption which makes sense, its a thicker oil, less flow, etc. I used T6 in an old corolla as a test. It definately ran quieter, smoother. No clear evidence of any dramatic cleaning. A little varnish on the stick remained, but it did clean a lot of it off. Oil got a little dirty, but not that bad. IMO avg cleanup, would be good as a prevent.

Reading oil consumption or cleanup threads the Castrol products, GTX, semi blends, etc. are commonly referenced as the oil that had been used. While it never gets the blame for dirty engines, theres no disputing that oil is mentioned quite often. In another forum I have followed a High Mileage teardown and rebuild (320k) for an oil consumption problem. Oil used for the majority of its life was Castrol Syntec blend @ 5k OCI. Upon teardown all the parts were good, no wear, but the engine had a bad case of varnish and a fair amount of deposit buildup on the oil control and scraper rings. The varnish that clogged the piston oil return holes flashed and hardened into a carbon mass. Cleaners were used on the piston after it was removed from the engine. Nothing could get it out, the holes had to be drilled out. The vvt-i controller was also stuck with deposits causing performance issues. It had to be completely taken apart and cleaned. So although Castrol syntec blend gave the engine a long life, would appear the oil choice caused the consumption problem.

Lot of claims about the power of Pennzoil as a cleaner. Is it hype or for real? Going to find out. I'm currently running PP in one of my cars, a synthetic convert. Not very dark so far, still has varnish on the dipstick at 4k. The engine was definitely dirty prior to PP. Oil was horrible looking, varnish on the stick, PO used OLM for OCI's on unknown dino. Have the service records. Lube shop dino. So..Pennzoil cleaning power inconclusive so far.

I'm currently using Mobil 1 High Mileage full syn in another troubled engine. Seal and gasket leaks, sludge and varnish from a PO neglected dino life. Went to maxlife first. Was an ok oil, appeared to be cleaning pretty well, but the varnish on the dipstick remained after 2 OCI's. Then I made the switch to M1 HM after reading the product sheet that claims "extra" cleaners. A ton of deposits came out after the first 2 oil changes. Chunks of sludge, other small particles. varnish on the dipstick was gone after the second OCI. Idled better. No leaks. I stayed with it. So IMO M1 HM is better than maxlife semi in more than one way.

The engine running M1 HM was staying fairly clean throughout a 7k OCI for thousands of miles. I added Kreen after reading about it on here. Boom, dirty oil fast again. Why was it dirty again? I can only tell you what the dipstick looked like. Dirty at 4k. subsequent OCI's with M1 HM/no Kreen - oil stays clean for the entire 8k OCI, so I "think" it helped even further.

So there's a small amount of data mixed with my own trial and error. Hope its useful.
 
Leakyseals.
That's good to know about mobil hm and it's cleaning ability. I know mobil 1 touts themselves as a cleaning oil but it's good to know the hm stuff also helps the issue.
Thanks for the info
 
Clevy - NP. I left something out. Did M1 HM solve my oil consumption problems? Depends what is meant by "solved". Will try to explain. Above I wrote about the findings of a high mileage teardown for an oil consumption problem. It was of special interest to me because its my engine. The one running M1 HM. As stated, nothing short of a teardwon and drilling out the piston oil returns can cure that consumption problem. I believe I have that problem in addition to other oil losses like valve seals and external leaks. This being said, yes its consuming less but not cured. Its still 1qt every +-4k which is twice as good as it was. Many would find that unacceptable. The only other option would be oil starvation with a thicker oil or a teardown do dig the pistons out. I'm not willing to do either. Its an old tired engine with an old tired body. I feel the combination of M1 HM and Kreen is my best shot. Going to start using small doses of kreen towards the end of every OCI, Use PEA fuel system cleaners more often and hope for the best. Attack it from both sides. If your consuming oil, your contributing to a fouled combustion chamber and ring coking long term. More oil you burn the more you should be using fuel system cleaners IMO.

So.. if the consumption problem is a combination of external leaks and engine cleanliness (ring coking vs my problem), then you should see good results with M1 HM and/or Kreen. But depending on the problem, nothing short of a repair will solve oil consumption.
 
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PCV valve is fairly new about 12k kms on it so Im not to concerned about it, will probably check just to be sure.

I just had the engine torn down to a short block to replace head gaskets,upon inspection everything was in surprisingly good shape , not a lot of varnish, cylinder walls still had a healthy cross hatch, even on the thrust surface where you would typically see a polished spot. cams and rockers in perfect shape. also still no cold start piston slap at the 238k mark!

while i was in there i had the heads freshened they were machined got new valve seals and a light valve job. every other gasket and seal was replaced and resealed as this frigen engine was leaking oil from everywhere. everything accessible was meticulously cleaned and reassembled. I contemplated removing the pistons but its a fairly large job on a EJ series horizontally opposed engine. I should have......

So I have no concern or need to swell seals or slow leaks, my number 1 and only concern is trying to clean up and free the ring pack.

One question is the M1 HM the mobil super2000 high mileage?

-Maxlife 5w-30 sounds like a safe bet, seems to get praise on here,
-any of the High mileage oils
-Rotella T6 5w-40 sounds like a good bet too,

Couple others that stand out and i can get easily
-Rotella T 10w-30
-Delo 400LE 10w30
 
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Originally Posted By: Chris_H
One question is the M1 HM the mobil super2000 high mileage?


No. M1 HM in the States is a synthetic with older API specifications. Our Mobil Super 2000 HM is a semi-synthetic SN/GF-5. If you're not looking to address leaks, the Super is probably a good bet. I tried it on my leaking truck and it failed miserably, where MaxLife did fine. That's not a knock on the Super - it just didn't do much for my leaks.
 
I have a 2.5 Subaru with 270,000 miles on it. Recently, about 20k or so, I've been putting in T6. No problems with it. I lose well under a quart of oil in 5,000 miles.

For the first 200k I ran Chevron 5w30 and I never had any problems with that. Dino oil might be cheaper if you keep burning it.
 
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