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2018 Foz 6MT break-in oil consumption (merged thread)

('14-'18) 
18K views 99 replies 27 participants last post by  adc 
#1 · (Edited)
I just bought a 2018 Foz, base model, 6MT.

After 500 miles my oil level dropped from about 2mm over the top mark, to about in between the 2 marks on the dipstick (according to the manual, this is about 1/2 quart).

I am breaking-in the engine per the manual, this is not my first time on a new engine.

**** I have read extensively these forums about oil consumption, and other issues of the FB25 engines ****

Quick questions:

1. should I be worried ? In theory, oil consumption would go down after the initial break-in of the engine and stop, or stabilize at an acceptable level. Still, 1/2 qt after 500 miles is a lot. Did anybody else experienced initial high level oil consumption ? How did it evolve as the mileage went up ?

2. Did anybody measured oil consumption with Amsoil 0w-20 ? or 5w-30 ? Amsoil has 3 oil recommendations for Foresters.

3. the manual insists on 0w-20 oil. I am thinking to use 5w-30 starting with my first oil change (~5000 miles). Anybody has any long term experience with this method ? Not considering the warranty aspect.

4. Let's say I'm not bothered adding oil, or spending extra $ for oil in between oil changes. I understand how internal combustion engines work, and how they are lubricated. High oil consumption can indicates major issues with the engine. However I have read posts on this forum by people who drove over 150k miles on an oil burner Forester ... Your thoughts ?

Thank you.
 
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#2 ·
2018 Foz 6MT

First and most important. Continue to monitor, too early to be alarmed.

My 2015 Crosstrek ‘burned’ a lot... brought in and it was diagnosed as a malfunctioning PCV valve. They replaced and from 4k to 37k... it lost never more than about .5-.6qt per 6k.

I think AMSOIL is top quality oil, and I tend to use their gear oils... but they aren’t technically API certified... so I wouldn’t use during warranty period or when watching for issues you might need to bring up with dealer/manufacturer.

Its probably technically ok and adequate for engine to use the 5w-30 spec as fxt/wrx... and it may lose less oil... but I would discourage this during warranty and when watching for potential warranty issues.

Don’t give them any reason to question you.


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#3 ·
Interesting, I will keep that PCV valve in mind. Any simptoms that would point to a faulty PCV ?

How would the dealer know what oil weight was used ? If there is any warranty issue, don't they have to prove that you used the wrong oil, and not vice-versa ?

I am not trying to convince anybody of my beliefs, just "thinking aloud" to clarify it in my mind: if the manual is ok with topping off with 5w-30 oil, that would logically imply that the 5w-30 is not harming the engine ... On a high oil consumption scenario, if the engine burned 5qt of oil in 6000 miles and you topped off with 5w-30, you could end up replacing your whole 5.1 qt of 0w-20 oil with the 5w-30.
 
#17 ·
... How would the dealer know what oil weight was used ? If there is any warranty issue, don't they have to prove that you used the wrong oil, and not vice-versa ?...
If there is a warranty problem that requires oil change records, it will be important to show that the recommended oil was used.
If you have not used the dealer for oil changes, your receipts will be used, which will show dates and brand/weight of oil.
If you produce receipts showing non-recommended oil weight, it will weaken your case. Unless the oil change interval is in question, it might be best not to show such receipts.
If you are building a warranty case, stay with the dealer all the way. Their oil, their changes.
Most car makers say 1 quart per 1,000 miles is acceptable.
 
#4 ·
You don’t need Amsol, get some oil at the dealer and top it off. Stick to the grade in manual. Do not baby it, though nowadays it probably doesn’t matter as much. Don’t make a big deal out of it, a quart in 3,000 miles is fine. Do make sure you add oil as needed though.

Stan
 
#5 ·
Hi Stan - I had 1/2 qt burned in the first 500 miles. Essentially the oil level dropped from about 1/8 of an inch above the top mark to about 1/4 of an inch above the bottom mark in less than 6 days.

Not babying it, I drove it as hard as I could under 4000 rpms.
 
#6 ·
When are you checking your oil level? Shortly after a drive or after it's sat a while? When you say you drove it as hard as you could under 4000 rpms did you do a methodic breakin...meaning wait until fully warm, do low rpm pulls to 4k and then engine brake to allow oil to be pulled back up the wall to keep lubrication up during those pulls, followed by varying rpms/load conditions?
 
#7 ·
Don’t overthink the break-in, just drive it as you would usually. If something is broken, let it fail early on but don’t do it by running low on oil as some on here have done. Let the dealer know, buy some oil from them, add half a quart and see if it gets you back to normal level.

I’ve dealt with 2 cars that use 0w-20 — a 2012 TSX I owned for a few years, and my wife’s Mazda 3 that she’s owned for a year now. TSX needed about a quart every 3,000 miles from when it was new to around 60K when I sold it (may have been a bit more initially), Mazda 3 has had no visible loss in 3,600 miles that she’s driven it. I drove the TSX pretty hard, Mazda 3 sees city driving only. Using heavier oil isn’t the answer IMO — I keep preaching that if people are worried about these cars running thin oil they shouldn’t buy cars that call for it. In grand scheme of things minor oil loss isn’t a huge deal. Obviously, a quart in 1,000 miles is not minor and should get addressed under warranty, but you have to establish that first.

For the record, I am not a fan of easy break-in, but I don’t think that makes a huge difference with new cars nowadays.

Stan
 
#8 · (Edited)
@scooby - I checked on a level ground (i have an airbubble level to check that the ground is horizontal :p), after at least 6 hours of letting the cat sit with engine off.
Yes, engine is warmed up (oil at ~200 F), then I start the break in, just like you said. Vary the rpms, pulls and engine breaks.

@Stan - will do, it's just my driving style, never babied any of my cars.
My main assumption is that the request for 0w-20 is not that the engine is designed for it, but motivated by stupid emission or mpg regulation. I could care less about mpg. And cows pollute our air more than cars .... just saying ...
As far as I know, the problem with super-thin oils is that they don't usually stick that well to cylinder walls and when you start the engine (warm, and especially cold) the oil is almost absent until the pump start pushing it around to create the oil flow. So you have a couple of seconds of metal to metal. I'm exaggerating a bit, just to make the point.

I appreciate your time folks.
 
#9 ·
You will get some people reporting 0 loss and others reporting crazy losses using 0w-20. But, that’s happened before also with other oil weights. My thinking is the oil will work fine, at least it did for me with 7K+ OCIs for 60K. Run heavier oil if you wish. Some have done that without any effect on consumption. Running 0w-20 in the XT would be an issue, but your car is designed for it.

Stan
 
#11 ·
I do engine brake regularly, but i don't go through all the gears until car stops. I've been driving manual all my life and it kind of happens automatically. For engine break-in I would for example go down a hill in second or third (depending on speed) with no gas, and let the engine brake the car - the rpm-s will slowly go up and the car does down the hill and slows down. On the other hand, on a level ground, or up a hill I would also accelerate from the second or third full throttle until about 4000 rpm-s and hold it for a minute, then switch into 4th and drive normally.... And so on.

My driving style is such that I often find myself around 4-5k rpms in the city. For highway, I would use 5th or 6th or even cruise if it's a long trip. Haven't done that with this Foz yet.

Definitely on a MT the rpm-s will be higher and vary more sharply. Every car I had so far had no oil consumption, or any other issues with this driving style. A well build engine with redline at 7k rpm-s or so should not have any issues at 4k rpm-s.

I drove all kind of automatics and CVT-s and I understand how they work, definitely lower engine rpm-s, maybe short peaks quickly resolved by switching to a higher variable gear (= lower rpm-s). CVT keeps the car at the lowest rpm needed to maintain the current speed. On a manual, the driver chooses the rpm of the engine - remember peak torque is usually around 4k rpm for most engines.

For example, if i want to pass on a 2way road, I would normally get closer to the the guy in front of me, switch to a lower gear (depending on the speed) that would bring the engine close to peak torque rpm, then full throttle, pass, merge back to the left lane and switch the gear back to 4th, 5th, etc, whatever the case.

On a CVT, in the same situation and assuming you don't switch to manual paddle shift, you would just floor the gas, the transmission will usually switch to a higher gear - but not always optimum torque rpms - and you can (slowly) pass. Traditional automatics, or double clutch automatics will react differently (usually better). The sport mode of CVT and automatics will usually keep the engine revved up higher so you have access to an optimized torque output.

Of course, even with MT I can drive in the city in the 5th gear an keep the rpm-s under 2k rpm, and that WILL give me better gas mileage, but the car will not be available for quick maneuvers unless you downshift. CVT-s keep the engine at that level rpm-s, that's why people say "CVT-s are better for mpg". Of course, because you move like a snail and let the engine chill.
 
#12 ·
Just monitor it and if it continues then bring it back... warranty for a reason!

Its not unusual for a new engine to consume a little bit of oil while breaking in. Also checking at different temps or ground levels will change the level too. Good to check with the same warmed up engine on a known flat ground to compare.
 
#13 · (Edited)
IMO what you are doing isn’t creating load. What I do is load up the engine, like going uphill, say, in 3rd gear while accelerating. Accelerate up a hill, then let off the throttle, repeat. But, again, may not be relevant.

What you are doing may actually suck oil past the rings while creating a hot condition since injectors aren’t firing, but I may be full of it.

What it takes to set the rings is cylinder pressure, and heat. Cylinder pressure makes the rings expand and press harder against cylinder walls, while rings rotate. Coasting downhill will not create positive cylinder pressure needed for this.

For RPM limits and torque curves — depends on the car. And you want horsepower while accelerating, so revving higher is needed. My TSX was very happy zinging past 5K, while the Golf is fine to lug under 4K. Depends on the car, but IMO the FB needs to rev.

Stan
 
#14 ·
I really like how this car drives and the engine opened up after these 500 miles. I'll keep going and see what's going to happen next. I would hate to have to get rid of it. Money wise as well.

If it keeps burning oil at this rate, will talk to the dealer - they will say it is normal - and I might talk to an independent Subaru mechanic as well. There is a Subaru specialized shop in my area.

There are no other option for manual SUV-s. Too bad. My other option was a 4Runner. The Foz won because of manual transmission. And because I got the sense from this forum and other sources that they fixed their oil consumption issues.

Maybe it will be ok. We'll see.

Great community, appreciate the input.
 
#15 ·
I certainly feel you on the manual transmission situation.

If you buy the oil from the dealer, at least that establishes you needing to do so to top off, may be good warranty-wise if you need to prove high consumption down the road. Otherwise, enjoy the car!

Stan
 
#16 ·
My 2018 6MT is doing the same thing. Added a quart at 935 miles. Added another at 1800+. Our 2014 2.0 Impreza did it too, but not quite as badly. They gave us a new short block for that car, which seems to have fixed the problem. My salesman (yeah, I know) said that he *has* seen them use a bunch during break in and then settle down, but I'm not holding my breath. If it keeps up, I'll be discussing it with them.
 
#19 ·
kmg, it seems like we got sister cars :) I really don't mind adding oil, question is, on such a high oil consumption, how much trust can you put in the car ? i wouldn't call it a keeper.

I will keep topping it off with dealer oil and I might go for the first oil change to the dealer as well.

At what mileage did they replace the short block ?

Did you brake in your new short block ? or just drive it normally from day 1 ? I would be interested how that behaves long term ...


@Menel - going to the dealer for top offs is just an annoyance for me, they are out of my way and it's not worth it. Maybe just to build a case ... That measn every weekend I would have to drive to the dealer. And they will probably overfill.

I will ask for an oil consumption test, see how that goes. Somebody said they don't do that before 6000 mi or so - is that true?
 
#18 ·
2018 Foz 6MT break-in oil consumption

If your dealer is even remotely respectable. They’ll give you free oil top offs to get between maintenance cycles... ESPECIALLY in the first 3/36.

Thats what you paid the big $$$ for a new off the lot car for, you should be able to make it scheduled maintenance to scheduled maintenance without having to service.

If your car cant get there without intervention... they should help, and in the process document your woes.

Go to dealer. Don’t get AMSOIL or other oil.


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#20 ·
Yes you should do their oil consumption test for documentation purposes.

I do not know about not doing it before 6k. I don’t know why though. Burnin is only 1,000miles.

I looked back at my crosstrek base 5mt spreadsheet. I got topped off to get to 6k, then drained so bad after that oil change a cel came on by 8k. They did pcv valve and oil consumption check then.


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#21 ·
Somebody else mentioned PCV valve in connection with high oil consumption.

It seems that it's cheaper for Subaru to finance repairing your engine than to implement a robust quality control on their cars. Very sad situation.

Menel, did that procedure fix your oil consumption ?
 
#24 ·
@setup you're reminding me to check my Wife's '17 Foz 6MT oil when I get off work today. Her Foz hardly burned any oil in the first 6k miles, but I need to follow up again nearing 10k miles. Sorry to hear of your troubles...hopefully your FB25 calms down or the PCV valve proves a case (interesting, this thread was the first I had heard about PCV attributed to excessive oil consumption).
 
#25 ·
As far as I know, a faulty PCV valve is a classic for increased oil consumption in engines. Google will confirm.

I went to the dealer and asked them to replace the PCV valve. "But it's not needed ... " whatever. After some talk, they did it.
Testing in the next few days.

I found references that Subaru recommends 5w-30 oil in Europe. A guy from Germany posted a pic of the user manual that states 5w-30 as recommended oil weight for Forester. I also found a picture of a Subaru oil jug "Recommended for all Subaru cars" (by MOTUL). Guess what was the oil weight on the bottle .... 5w-30.

Plus a news article on a japanese site, where Subaru clearly states that recommended oils for the FB25 engine are : 0w-20, 5w-30, 5w-40.

http://car.watch.impress.co.jp/docs/news/20101022_401853.html

Do a google translate, the reference is a bit down the page.

Hmmmmmmm ....
 
#26 ·
At what mileage did they replace the short block ?

Did you brake in your new short block ? or just drive it normally from day 1 ? I would be interested how that behaves long term ...

The Impreza was burning a quart every 1200 to 1500 miles. I figured out about the oil consumption tests eventually. They made me do it twice. And the first time they overfilled it. Glad I caught that. They replaced the block at 15686 miles. We broke it in per the manual, same as the first time.
 
#27 · (Edited)
@kmg - They did not replace the short block, they replaced the PCV Valve at my request. This is a valve that releases the pressure from the lower part of the engine (blowback) back into the intake. If this valve is malfunctioning it can suck in oil mist and push it into the intake, therefore creating the same symptoms as if the engine would burn oil.

It's a small chance but wanted to eliminate the PCV valve from the equation. Trying the simplest solution first ...

Still testing it, I have 850 miles so far, and I added about 3/4 qt of oil so far before the valve change. I wanted the dealer to do this so I have a papertrail if this develops into an oil over-consumption issue later on.

By the way, I had to pay for this whole thing, and they told me oil changes will NOT be free, $70.- a pop, parts and labor. No thanks Mr. Dealer, will do my own.

Did the shortblock replacement fix the oil consumption issue ?
 
#28 · (Edited)
Subaru recommends 0W-20 vs 5W-20 for two reasons. 0W oil flows better at very low temps and 0W-20 will be a better oil than 5W-20...meaning it will require more Group III or Group IV (synthetic base).
Has nothing to do with emissions. 20 wt oil is specified over 30 wt bc of gas mileage increase.

Chances are that if a vehicle initially burns oil it won't decrease a whole lot. Been my experience over many vehicles.

Just an aside ..my 2016 Chev Spark has used no detectable oil in the last 7500 miles (20,200 miles) The oil is still light gold color. Usually if your vehicle is using oil you will find it getting darker quicker. I am not saying this oilj will be "bad" I am just saying the two (oil use and color) frequently go hand and hand.

My 07 Forester is using about a quart/3500 miles
 
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