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30 wt. Oil in the FB-Your Results (merged thread)

('09-'13) 
120K views 371 replies 69 participants last post by  bingow 
#1 · (Edited)
I thought I would start a new thread for those FB owners that decide to boldly "Go where no man/woman has gone before." Many realize that some FB engines use an excessive amount of oil. Perhaps there are those that will throw caution to the wind and try a heavier oil..... Subaru recommendations not withstanding.

Those that go this rout would hopefully share their experiences with respect to mileage and oil consumption. Obviously oil analysis would be great. Of course Subaru will not endorce this idea and let no one here think I am saying it is a great idea. But If I owned an FB I would certainly go this route.

The thread where this thread comes from is here
http://www.subaruforester.org/vbull...erged-thread-119562/index122.html#post2156865

It was getting off track (my fault) so I thought I would correct the issue. I would hope this thread does not become argumentative. We understand it goes against Subaru's recomendations. But it is the consumer's right to do as he pleases..warranty considerations not withstanding.
 
#2 ·
I decided to repost this bc it is what led to this new thread:

I am surprised folks here have not tried to see what occurs by say doing a mix of 20wt and 30 wt or really going to 30 wt. Subaru will never be able to figure out that you used a thicker oil.....bc if the engine fails the oil will also have failed and post disaster viscosity will be meaningless.

it has been proven when vehicles started with 20 wt oil (around 2001) that engines would not last as long. Origionally the EPA demanded I believe a 150K durability test. Ford was not able to reach that value and the results were that the durability was pushed back to (*I believe 125K miles). So why would you run with a 20 wt oil that is guaranteed to lower engine durability?

I have given this a bit of thought and have reversed my opinion. I previously felt that 20 wt oil was not a problem. Well for some engines (including Subaru FB IMHO) durability and apparantly normal operation is adversely affected.

So my recommendation [disclaiomer: do so at your own risk] would be to go with a 50/50 mixture of 20wt and 30 wt.

I am a mechanical engineer with a fair amount of lubrication experience. I have participated in equipment troubleshooting as a maintenance supervisor for 30 years in a power plant. I have spoken to oil industry tech reps. In addition I have done numerous oil analysis on my personal vehicles. I have mixed many different brands of oils and have also mixed diferent visocities of different brands. I have never seen any problems.

But again..do so at your own risk. You are doing what Subaru would not recommend. However if you read the Magnuson-Moss Warranty act..my intrepretation is that if your actions result in damage to the vehicle its your dime. My personal opinion though is that it won't and Subaru can not prove it did (The burdon of proff technically is on them)
 
#5 ·
This is a pretty good idea to get an idea at least if using the heavier weight oil does make a difference.

Personally my '14 Forester with the 2.5i motor does not use any oil, at least not yet (5500 miles). So I cannot contribute to this poll.

I would have to assume though that the heavier weight oil will contribute to loss of miles per gallon. Subaru says to use 0W-20oil for a reason, not only for maximum lubrication, but also to attain maximum miles per gallon. How much of a loss of MPG is anyone's guess at this point.

So you have to weigh both issues, using a heavier weight oil to avoid oil consumption, but use more gas to do this.

Still though, it's worth a try.
 
#6 ·
I would have to assume though that the heavier weight oil will contribute to loss of miles per gallon. Subaru says to use 0W-20oil for a reason, not only for maximum lubrication, but also to attain maximum miles per gallon. How much of a loss of MPG is anyone's guess at this point.
The estimate when the 20Wt came out was 2% better mileage
 
#7 ·
I'm sure alot of people will be following this thread as well as the excessive oil consumption thread. But I really think there is a mechanical/design problem with the FB engine not the weight/grade/viscosity of the oil. If the 0W-20 oil was the sole cause of excessive oil consumption then every owner of a Forester who has a FB engine would be complaining. But that is not the case. Some are experiencing excessive oil consumption and others are not. Quality control/inconsistent tolerances in engine manufacture? Anybody else agree with me?
 
#11 · (Edited)
It would be nice to know if the FA and FB20 engines have the same problem. The FB25 is a long stroke engine and the FB20 is square. I do suspect it will require a major redesign to solve...Maybe even a new block cast. The Subaru engineers know exactly what the problem is and since it is not fixed yet....It is at least somewhat major. It shows up in such a small number that they have basically blown it off for now. I am 90% certain that it is a piston/ring/cylinder design flaw and oil is getting past the ring pack on a small number of engines. Another problem downstream is that the oil additives are going to poison the catalytic converter over time...It is cheaper for Subaru to change a cat than replace the engine. I suspect Subaru is working on a DI version of the FB25 for the very near future. Maybe the fix will come then. Honda (R18, 2.4L Earth Dreams) and Toyota (2.5L) have designed off-center cranks to help mitigate forces in the piston/ring pack/cylinder area. I don't know if the FB engines have this design.

Never "baby" a new engine! and never change the factory fill oil early! It is important to seat the piston rings immediately when engine is brand new. Most engines are pre-seated at the factory now but you really don't know for sure. Load the engine right from the dealer lot for the first 50 miles or so...Meaning - climb a hill in 6th gear or similar keeping RPM under 4000. High RPM "Lugging" the engine produces cylinder pressure that pushes the ring pack against the cylinder. Failure to achieve proper ring seating in the first moments of an engine life can result in using oil for its entire life! Seating rings properly also makes the engine stronger at lower RPM and adds to engine smoothness and longevity. If you baby the engine from the start, you can have a oil drinking weakling forever :)

It would also be good to know if the engine used oil from the very start or if it developed a "drinking problem" after 1000s of miles. If the engine isn't using oil after the first change, then I doubt it will ever use oil.
 
#14 ·
And the BRZ's "OK" oil consumption spec is up to 1.1 U.S. qt. per 600 miles = 1 U.S. qt. per 545 miles:

● If your vehicle consumes more than 1.1 qt. (1.0 L, 0.9 Imp. qt.) every 600 miles (1000 km), contact your SUBARU dealer.

Ref: 2013 BRZ OM Version D, page 297

:icon_eek:
Jim / crewzer
 
#16 ·
To add fuel to the fire, this is my 7th new car. I've never "broken them in" other than to drive them all gently from day 1. None have used an excessive amount of oil (unless you consider my present 1 Qt/6K mile excessive).

I, however, changed my factory fill at 7.5K per the manual.

This is just me. I suspect most other break-in methods (or not) and/or change intervals work just fine too.
 
#17 ·
I would have to agree with you about breaking a vehicle in. I have owned 7 vehicles as well and always take care to keep the revs down and "baby" them while breaking them in. Not one of the vehicles ever used a drop of oil between recommended oil changes, so I don't subscribe to the theory that you have to keep the RPM's up and drive agressively to properly seat the rings in the engine. If there is a fault with the FB engine(which I think almost everyone on this thread thinks there is)no matter how you break the engine in, it is still going to use oil. Agree or disagree?
 
#18 ·
How can you say there is a fault in the engine when it's obvious majority of people are not having issues?

The engine break-in doesn't have to do specifically with RPM, it has to do with load and heat cycles. You could load up the engine going up a hill at 3K RPM and it may be sufficient.

Stan
 
#22 ·
Well Gent's, my story will start here then.
Just dumped in the last of the 0w-20 and recorded the mileage. Went to local store, they didn't have the 0w30 I was considering so I got the 5w-20 High mileage Mobil1 to start.
Suppose to reduce oil consumption so they claim.
See what happens with it. I will start adding it as the level drops.

I am still going to go after Subaru about this problem as soon as I can figure out who to communicate with.

If I had known at the time I bought this that is was the first year for a new engine, I would have bought a low mileage 2010 instead of the new 2011.
 
#23 ·
I've been reading all the excessive oil consumption threads with a lot of interest. For some reason discussion of oil always interests me. First, I have a 2013 n/a Forester with just over 9k miles on it. It uses about .5qt every 4k miles. I've only used 0w-20 so far. Next oil change, I'll use 0w-30 or 5w-30. Not necessarily because of oil consumption but because it's better for the engine.

Here's the deal. No engine is designed to use such a thin oil and every engine that you use 0w-20 will burn oil. Some more than others. If you think I'm wrong, visit any forum for any manufacturer and you'll see people with all the same complaints. This is not a Subaru thing.

So, why do manufacturers recommend it?? They recommend it because EPA fuel economy tests are run starting with a COLD engine, so the lower viscosity reduces friction until the engine warms up. That's also why you can find people all over the place say they have the same mpg ratings after switching to a thicker oil. Even if you do loose some small mpq percentage, you'll spend far less money of extra fuel then on adding oil and your engine will last longer. Manufacturers are doing everything they can to increase fuel economy ratings, even if it means burning some oil and a shorter engine life (I'm guessing they figure an engine running thin oil will still make 150k miles, or more than most people will go).

I guess I'll add this is just my opinion based on the research I've done. Anyway, you won't see me running any more 0-20 and I love my subie!
 
#24 · (Edited)
Here's the deal. No engine is designed to use such a thin oil and every engine that you use 0w-20 will burn oil. Some more than others.

I guess I'll add this is just my opinion based on the research I've done.

I almost missed the last line where you said this was your opinion, glad you added that because in my opinion this is bullocks.

There is a reason 0W-20 is used in modern engines. 1st the tolerances between moving parts are now so miniscule that heavier weight oils will not pass through these parts and you will have engine wear. 2. Less friction. Which in turn will give you much better gas mileage than using a heavier oil. 3. I ONLY use 0W-20 in my '14 Forester and do NOT use any oil after 5500 miles of driving. 4. The reason some of the FB25 engines use some oil is because the rings are not seating properly, this has been discussed on here in length. Why on some motors they are not seating right is anyone's guess right now. Hopefully Subaru soon will find out.

The only change I would make in oil weight would be in summer run 5W-20 and in winter switch back to 0W-20 which the manufacturer recommends.

If you start over messing around with oil weights not recommended by the manufacturer you could void your warranty. Not creating FUD, but think about this first before experimenting with different oil weights.

My opinion only.
 
#25 ·
...EPA fuel economy tests are run starting with a COLD engine...
Yes and no. Check this link to the EPA testing procedure, and then select the "Detailed Comparison" tab on the chart. Two of the five tests involve a cold startup, but the remaining three tests use a warm startup.

HTH,
Jim / crewzer
 
#26 · (Edited)
Interesting points you make. I have to say I did leave out a million things so not to write a book and I actually agree with a lot of what you say.

But, the point I really wanted to make is automakers have switched to 0w-20 oils to meet strict fuel efficiency requirements. They did not switch to 0w-20 because it was better for the engine.

Really, you can run any weight oil. Thin oils will be best for cold conditions on start up, thicker oils better in hot climates and long drives. Thin oils will burn up faster and you may need to add some every 1000 miles. 0-30 or 5-30 is probably the best compromise for most people in my opinion.

One more thing. Engines use oil for many reasons, not just because rings don't seat properly.
 
#29 ·
Well, I know I started discussing why I think 0w-20 is too thin for all cars. But, like I also said, I tend to us .5qt every 4000 miles with 0w-20. I will post back my results when I switch to a thicker oil. Unfortunately that will be some time from now and I'll be comparing winter results to summer results.

I'm really curious if anyone tried this a while ago as I'm curious to see the results. So post up.

I'll bet I can find this same thing over on Toyota, or some other brand's forum.
 
#30 ·
The FB25 in my 2013 2.5x is not oil thirsty, first oil change at 2995 miles using Subaru 0-20W (free oil change at the dealership) at 8800 miles it was low enough on the dipstick to take a full quart.(Subaru 0-20W). Second oil change at 10501 miles,(at the dealership with 0-20W) now at 13434 miles, still only 1/2 way to the lower mark on the dipstick. No complaints here!:woohoo:
 
#31 · (Edited)
I'll agree with Tony on this one. Today's oils are better than those of 20 years ago. If the engineers are saying 0w20 should protect the engine well, and you aren't seeing issues -- why change? Your 1/2 quart in 4K usage sounds pretty reasonable and is similar to my Acura's 1/4 to 1/2 quart usage in 5K OCI. I just got over 3K after my last oil change and splashed a bit in here because level was a hair below the top mark -- I like to keep it at or above that mark. Most would have probably left it as-is. 20K since new, using 0w20 blend from the dealer, so far so good. I was very worried initially.

I can and have pointed to threads of people going through oil with the same car I'm driving, this problem shows up in other cars for sure and isn't isolated to Subaru. Also want to point out numerous complaints from owners of previous years Subarus which called for 5w30, this is nothing new in this community.

Stan
 
#32 ·
Stan T, you are correct. burning only .5qt every 4000 miles is very reasonable when using a 0w-20 oil. I just think a 5w-30 will extend my engine life, that's why I might switch. I probably should have posted on a different thread but I posted here because I also think moving to a thicker oil will solve a lot of oil loss problems others are having and I'm curious to see if I'm correct.
 
#33 ·
In the excessive oil consumption thread, belik(who is from Russia) posted that the recommended oil in the owner's manual is 5W-30, so I would tend to think that the only reason 0W-20 is recommended by Subaru here in North America is for fuel consumption ratings. If the engine was really only designed for 0W-20, they wouldn't say 5W-30 oil is the recommended oil for use over there. So I really don't see any problems in using 5W-30 oil. Also, if I was a betting man, I would bet that a engine that only sees 5W-30 oil from day one will last longer than one run on 0W-20. Time will tell.
 
#38 ·
In the excessive oil consumption thread, belik(who is from Russia) posted that the recommended oil in the owner's manual is 5W-30...
There was a bit of confusion over this issue. Belik ultimately confirmed that 0W-20 is recommended for the Russian market.

Regards,
Jim / crewzer
 
#34 · (Edited)
"unless you consider my present 1 Qt/6K mile excessive"

Yes I do. 1 qt in 10K miles is excessive (My car uses maybe 6 oz in 8K miles).

Loading the engine when new seats the piston rings against the cylinder walls...This is physical reality. There is nothing "aggressive" about this nor does it requires aggressive driving (Make the engine sound like a "bleating cow" at 1600 RPM :) ). Most engines are seated at the factory now but it can never hurt to load up a new engine. The manufacturing, CAD/CAM, and honing techniques are excellent today and don't require as much seating (especially those who use plateau honing). It could be the difference of an engine using 1 qt per 6K miles and nearly none.
 
#35 ·
"How can you say there is a fault in the engine when it's obvious majority of people are not having issues?"

Designing "low friction engines" can lead to very tight tolerance on the "hairy edge"...some engines can fall over the hairy edge if inadequate factor of safety. Blame CAFE and the upcoming MPG fines these companies (cost past on to customers since companies don't have money until customers give it to them) will have to pay in MY 2017.
 
#36 ·
"No engine is designed to use such a thin oil and every engine that you use 0w-20 will burn oil"

The viscosity of 0W20 is not the problem. If fact, low viscosity at cold start is much better with 0W20. NOACK can be a problem.

If you want a low NOACK 0W20 try Redline oil, but it is oil NOT recommended by Subaru and it is $10 per quart.

I might try 0W20 in my EJ25 just to see if it uses it.
 
#37 · (Edited)
The viscosity of 0W20 is not the problem. If fact, low viscosity at cold start is much better with 0W20. NOACK can be a problem. .
There is not enough difference between 0W-20, 5W-30 or even 5W 40 down to 0F to have any meaningful affect on engine wear during cold start.

The first number is widely misunderstood. I think many people (not necessarily you) are concerned that somehow a 0W oil is to thin for summer use.. The fact of the matter though is that a 0W-30 oil is still 8 times "thicker" (about 80 cSt) at even 100F than an engine running at 200F with a 30wt oil (say 10W-30). The first number is really only a measure of the viscosity of the oil at temperatures less than 200F. And technically it specifies the cold cranking viscosity (in centipoise) vs specific low temperatures. These are definitions.

Only at engine temps near operating conditions is the second number relevant (10cSt for 30 wt oil)
 
#45 · (Edited)
Well, I don't want to be argumentative, but I want to bring forth my thoughts as to why a 5W-30 wt oil will not harm the FB engine. And remember in countries other than the U.S. 5W30 is the recommended oil so presumadly 5W-30 does not lead to engine damage (outside the U.S)

Mobil 1 Specs:

0W-20@40C 44.8 cSts
5W-30@40C 61.7 cSts

Not a very big difference really and consider that both oils can presumably run at 0F where viscosities will both be in the 1000 cSts range and yet can be expected to start thousands of times with no damage. And consider that the engine can operate thousands of hours with a syn aty very little wear on a timing chain where the viscosity is a mere 8.7 cSts

How is it that oils well between these two extremes (0F and 200F)...one oil with a difference of 17 cSts would cause more wear than the other oil...again for that short starting/warming ujp period.

Also consider when you restart up your car hot (occurrs very very frequently)..you are starting it with a viscosity of 8 cSts...shoud this not be a problem??

Again..just pointing out why a 5W-30 oil will not harm the FB25 engine. Again, just MHO and goes against Subaru recommendations
 
#40 ·
All have interesting points. Unfortunately for me there seems to be many opinions.
My 2011 uses 1qt. per 1200 miles.

I really don't think Subaru is going to do squat when I complain. I will try the 5w20 for every season except winter. I will keep you all posted.

I am starting out with a mix of 5w and 0w. Getting tired of having a total oil change before my scheduled oil change.
 
#41 ·
If you are going to try a 5w20 then I would recommend Pennzoil Ultra since PQIA tested Ultra 5w30 at 6.6 NOACK which is outstanding. Chances are good that they use the same excellent base oils in their 5w20. 1 qt per 1200 miles is just awful unless you are beating the thing around a track.
 
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