Oil recomendation for subaru burning and making oil dirty

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5
Hi, sorry if this has been covered, it's not easy to search for.

I am looking for recommendations for oil, filters and oil change interval.

We have a 2007 Subaru with the 2.5i NA engine. We bought it well used (to put it nicely), and it has burned oil at a rate of about 3/4 Qt per 1K miles for the last 50K miles, the whole time we've had it. It also makes the oil very dirty rather quickly. It leaks a little oil, possibly from the oil pan, and I think from one of the valve covers, but not too much, no puddles on the driveway. I have been using mostly Mobil 1 5W30 HM in it, but I have also occasionally run Penzoil HM Synthetic and more recently Walmart Supertech Full Synthetic HM. None appear to burn less, but my last change with the Supertech looked extremely sooty at 5K miles, which is my usual OCI. I have used Subaru, Fram, and recently Supertech oil filters.

This last sooty oil change was with a Supertech filter. I took apart the Supertech filter and it's construction seemed good, metal end caps and core, but the filter media in the tiny filter is shockingly small, there can't be a whole lot of surface area there for filtering. I put in Mobil 1 oil and a fresh Supertech filter. I may change the filter out after 2-3K miles this time to see if that helps.

Given the rate at which I have to add oil and how dirty the oil gets, I am considering going to conventional oil to save some money, and going to a 3K OCI. I would like to pick a conventional oil that has a good additive package to handle the soot and not sludge up the engine, and a HM might be good for the leaks I have. I am also considering spending a little more on the filters. I can get Subaru or Wix filters for a few dollars more than the Supertech and I think the bypass pressure settings would match the Subaru specs, the Supertech may be considerably lower. The Subaru filters seem to have cardboard end caps similar to Fram, which is why I gave up on them, but I suspect they would be fine for a reasonable OCI.

What's a good oil maintenance approach for this car? Thanks! -- Jim
 
Messages
1,967
Location
USA
Based on your account, vehicle condition and desires, it seems to me....

Go with any brand HM ( base purchase on price) with a medium range filter ( base on purchase price) and move to a 3k OC

There is no miracle additive or secret sauce oil that will offer you any tangible or sustainable benefit in your specific condition based on your assessment of the mechanical condition of the engine so my advice is don't go chasing ghosts. Same with the filter.
 
Messages
32
you could try 10W30 DEO it has good cleaning agents and may slow burning down a bit. Thats what I run in our Jeep liberty that uses oil. It did slow down going from 5w30 to this. I run Rotella 10W30
 
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15,509
Location
N.H, U.S.A.
Have you checked the PCV? Too bad there wasnt room to get a boxer piston out but pulling a head and dropping the pan. But there is a "secret" way if you push the full loating pins out using acess ports in the block ends.. Then you can carefully hone and re-ring.
But why the synthetic? Its doesn't "protect" better - plus you are way past needing "protection" whatever that is. Silly marketing term. Its like home or life insurance - its doesn't protect you from disaster. Stuff Happens.

Do a good health check on the PCV system - and dont over foll the oil Subaru 2.5 love to burn off filled oil. Run it a t leat a quarter qt low - MAX then run it down until its almost at the fill mark. I would run a mix 1/2 10w40 and 1/2 5w30.

I've Owned 8 subarus and seen most of their hijinks. form Justy to the flat 6 SVX "exotic"
 
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2,560
Location
wv
Getting 'sooty' from the blowby.. poor piston ring seal.

This is pretty 'normal' for those era Subarus.

Side effects of consumption are more than dirty oil. Spark plugs and catalytic converters are seeing more of the combustion processes

Theres no sense in pouring expensive oils into your oil burner.. nothing to gain.

T5 10w30 would be a good starting point and monitor consumption.. a basic filter and 3-5K oci wouldnt hurt.
 
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Messages
2,492
Location
NJ
Given that your owner's manual allows for 10W-40 down to -4F, I would go with a conventional 10W-30 High Mileage next. And don't stress out about the oil filter either. IMO, that's one of the most unnecessarily focused on aspects of oil changes in a Subaru. I've stuck with the OEM Honeywell about 80%+ of the time and ran whatever came free with an oil change bundle special the rest of the time.

I run 10W-40 High Mileage during the summer to curb my turbo's drinking problem, but I think the n/a cars seem to take more of a hit in peppiness when going too thick.

And ditto on the PCV!
 

Jim22

Thread starter
Messages
5
This car has had it's cat replaced, did that a couple years ago with good results so far. I put in Walker cat I believe. I have also changed the PCV valve and I don't believe there are any clogged hoses. Curiously, it did throw a PCV code recently, but that seems to be just an electrical jumper that might get interrupted if a hose physically separates, which was not the case. I should probably take a look at the plugs, they were done a couple years ago.

I agree with not over-filling the oil, especially since there is a possible leak in the pan. I put in the 4.5 qts it calls for, which fills it just to the full notch on the dipstick. I could certainly reserve 8 ounces of that to put in after 1K miles.
 

Astro14

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12,310
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Virginia Beach
HM oil - any good brand. Good filter. Change every 3,000. Replace valve cover gaskets.

Best you can do. Nothing that comes out of a bottle will fix your leaks, or restore your engine, but you can help it out by changing the oil more often, before it gets loaded up with carbon, as you suggest is happening. It’ll last a long, long time just as is, as long as it has reasonably clean oil.

Of course, you’re adding 4 quarts in that short time, so you're practically changing it twice every three thousand...
 
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1,106
Location
NC
Supertech 10w30 conventional and call it a day. Supertech 10w40 High Mileage if you're feeling like splurging on it. Oil filter of your choice, Supertech oil filters are pretty good for the price.
 
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4,559
Location
Decatur AL USA
Why do people recommend thicker oil if they think it's the rings? It's been my experience thicker oil only really helps with valve guide / seal issues.
 
Messages
359
Location
North Carolina
Hi, sorry if this has been covered, it's not easy to search for.

I am looking for recommendations for oil, filters and oil change interval.

We have a 2007 Subaru with the 2.5i NA engine. We bought it well used (to put it nicely), and it has burned oil at a rate of about 3/4 Qt per 1K miles for the last 50K miles, the whole time we've had it. It also makes the oil very dirty rather quickly. It leaks a little oil, possibly from the oil pan, and I think from one of the valve covers, but not too much, no puddles on the driveway. I have been using mostly Mobil 1 5W30 HM in it, but I have also occasionally run Penzoil HM Synthetic and more recently Walmart Supertech Full Synthetic HM. None appear to burn less, but my last change with the Supertech looked extremely sooty at 5K miles, which is my usual OCI. I have used Subaru, Fram, and recently Supertech oil filters.

This last sooty oil change was with a Supertech filter. I took apart the Supertech filter and it's construction seemed good, metal end caps and core, but the filter media in the tiny filter is shockingly small, there can't be a whole lot of surface area there for filtering. I put in Mobil 1 oil and a fresh Supertech filter. I may change the filter out after 2-3K miles this time to see if that helps.

Given the rate at which I have to add oil and how dirty the oil gets, I am considering going to conventional oil to save some money, and going to a 3K OCI. I would like to pick a conventional oil that has a good additive package to handle the soot and not sludge up the engine, and a HM might be good for the leaks I have. I am also considering spending a little more on the filters. I can get Subaru or Wix filters for a few dollars more than the Supertech and I think the bypass pressure settings would match the Subaru specs, the Supertech may be considerably lower. The Subaru filters seem to have cardboard end caps similar to Fram, which is why I gave up on them, but I suspect they would be fine for a reasonable OCI.

What's a good oil maintenance approach for this car? Thanks! -- Jim

I have a vehicle who's engine produces sut and I bought it brand new. It's a 2018 Hyundai Santa FE Sport with the 2.4 GDI engine. I always used Mobil 1 EP 5W-30 in it and it darkened it pretty quick after an oil change. Then last year I got dealer bulk (I asked for synthetic, probably go a cheap dino or blend) because they wouldn't take my oil jugs for the oil change and I was caught up doing somethig else. Anyway, I did around 6500 miles on the crappy dealer oil and OEM filter. When I drained the oil it was pitch black and smelled disgusting. I couldn't get that smell out of my nose for about a day or two. I replaced it with Castrol EDGE 0W-40. Two days ago I did my third oil change with Castroil EDGE 0W-40 and finally the smell was gone. What came out smelled like oil. It was dark, but not pitch black. This was a 3000 mile oil change, the other ones where 1500 and 2000 respectively. The engine runs silky smooth and I'm happy with it. Now when I pop the oil filler cap I can see shiny silver metal inside, it's that clean.

Give Castrol EDGE 0W-40 from Walmart a try, I doubt you'll regret it. I cleans really well and protects your engine. Mobil 1 FS 0W-40 is also a high detergent - high anti wear additive oil, however, if you have an old motor with problematic fuel injectors and wear, I heartly recommend Castrol as it stands up better to sut and fuel dillution than Mobil 1 FS. If you go through all the other motor oils in the 0W-20 -> 5W-30 range you will just go in a circle. Just my personal oppinion, others may give different advice or disagree with me and it's their right to do so.

[Edit]

I also agree with what @ka9mnx said, however, my motor oil recommendation stands.
 
Messages
580
Even cleaning it might help :)
I used to change my PCV valve like every 20k or sooner, since I was new in my service advisor career, still a teenager and anal about the maintenance on the only things I cared about (my cars). Now, don't remember how many years ago I replaced them on my 83 Caprice and 84 Olds. O pull them out occasionally and inspect, shake and then put them back in.
Back in the day I had an oil burner 305 that had been overheated, burned a qt every 500 miles, it probably needed it changed sooner but nowadays they seem to last forever even on my old engines. They use about a qt per 2500 miles.
 
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