Excessive oil consumption issue?

Difficult to ascertain.

Supposedly only certain vehicles are affected, but at the same time it appears that engines were designed to consume more oil. Owners Manual and Subaru itself warn of higher oil consumption:

"Oil consumption of 1 litre/quart per 1000 miles to be considered normal" (!).

I think they clearly designed an engine that consumes a lot of oil.

This is mainly about the FB engines, the turbo is another type, the FA. Some say it is also affected.

Supposedly next generation Subarus are to get different or somewhat different engines.

Basia

My opinion is that one quart of oil used in 1,000 miles of driving is excessive. If it was normal, both my 2014 2.5L Forester and my 2015

2.5L Outback (as well as my son's 2014 2.5L Forester) would be using some oil within 1,000 miles. There are no consumption issues with any of these cars we have. The issue has affected some 2.5L engines but not all and, thankfully, our cars are not among those having consumption issues.

Bizarre that Car Consumption is soo Much There technology probaly !!

Also I noticed there is a TSB out regarding poor idle. TSB 11-130-13R Maks me feel uncomfy. All our car including older Subaru never had oil issues. In particular my Acura MDX never used oil between oil changnes. Poor idle affects remote starter I installed on Veteran's day holiday. Remote starter is having difficulty learning tach signal. Often it starts after 2nd, 3rd try. It is not good when weather gets cold. Contemplating going back to Acura this time for smaller RDX. These two issues start bothering me.

I was aware of the issues prior to buying the 2014 Forester. It will be two years old on New Years Day and has over 40,000 miles on it already. I wasn't worried about the issue, if my car turned out to be one of those with the issue then I felt confident it would be taken care of by Subaru. Last February we needed to replace our other car and we went straight to the Subaru dealer for a 2015 Outback. We have never regretted for one minute buying either car.

Have you taken the vehicle to the dealer for the idle problem? If it is a known glitch then they should take care of it for free -- if it is just a problem with your vehicle then you might have to pay depending on its age. I've not known anyone with a Subaru oil consumption problem and they are very common around here.

One case I read, this guy had 2 engines replaced for the reason. Did not solve the problem. Had to use quart every 1200 miles. First replacement engine was worse at very 900 miles. Second one was at

1200 miles back to square one. Whether I can take a chance waiting for the outcome, or as preemptive strike go back to Acura. Poor idle issue is from misadjusted cam sensor gap or mispositioned sensor from factory.

Vehicle is under warranty.

As little as 30 years ago 1 qt in 1000 miles was considered low/normal oil consumption, running straight 30 weight oil.

A quart in 1000 miles today is on the high side of normal/acceptable.. Oil seals on the valves, or poor seating of rings - either due to bad breakin procedure, loss of tension due to overheating, or rings sticking due to improper maintenance. Does the car puff blue smoke when started cold? If so - valve seals.

Otherwize, try something like Marvel Mystery oil to unstick rings if they are stuck. I have had many situations where that solved excessive oil consumption. I'm assuming at one point the oil consumption was normal?

If not, the rings may never have broken in and a trick we used on the first AMC engines with chrome rings may solve the ptoblem. At a fast idle, slowly sift a couple tablespoons full of dry Bon Ami scouring pouder into the intake. The very mild abrasive action of the powder deglazes the cyl walls and seats the rings. Change the oil immediately after, (NOT synthetic - a cheap 10W30 is adequate) then drive the car at varying speeds with cycles of full throttle followed by closed throttle decel for a few hundred miles and change the oil again, using a quality "standard" oil and see how the consumption is. Had many go from 1 quart in 500 miles to less than a quart in 2000 with that treatment back in the late sixties. Some guys did it with corn starch instead of BonAmi and it worked too - pretty much the same effect.

The Subaru oil consumption problem might be something different than classic oil burning. A number of people have suggest it may be caused by evaporation; thin 0w-20 oil creating a vapour, an oil mist, that gets evacuated from the engine, and burned by the catalytic converter.

Too bad Subarus approach is to be completely quiet and not inform the public nor owners of problematic cars about the underlying true cause of oil consumption.

If I had a car that was affected I'd use liberal doses of Marvel Mystery oil in the gasoline, unless it was a turbo. Some of it always makes it past the rings and into the crankcase. That way it replenishes oil, albeit with with thinner than recommended oil weight, Marvel is around straight 0, or so. Turbos want high octane; Marvel in gas kills octane, so not a good idea on a turbo. Basia

Surely you njest!!! Oil in the fuel will NEVER make it to the cranksase.. If it is as you suspect an "evaporation" problem, going back to a 5W20 or 5W30 would make a BIG difference, and so would running synthetic. If it is an oil mist problem, it will also go away to a large extent by running half a quart or so low, to keep the oil from being whipped up by the crank.. Using 1 quart less oil than recommended, and using a

10W40 synthetic oil would almost totally eliminate this type of oil consumption - just watch to make sure the oil level does not drop below that 1 quart low mark. This is a way to diagnose the problem - not necessarily a cure (but it was the cure on a friend's stock car with a souped up Chevy six that was throwing oil all over the track untill I marked the dipstick an inch lower - meaning just about 2 quarts less oil in the crankcase (6 instead of 8)

Also, if you pull the front O2 sensor from one bank at a time and run the engine you can tell if there is oil smoke being cleaned up by the converter.

On my 3.o MitsoShitty I was using a fair amount of oil, which was killing the converter - and never showed any smoke. By opening the exhaust before the converter I was able to determine what was going on

- bad valve guides that smoked like crazy on startup..

So why is it that whenever I use Marvel Mystery oil regularly in fairly large doses, approximately 10 ounces per 10 gallons, I always experience a steady albeit small rise in oil level on my dipstick?

The car is a 2000 Impreza 2.2L.

Basia

ps. the best fix might be to just leave it alone replenishing oil frequently. I am not a mechanic and Subaru plays mum, ...so anybody's guess.

Correction: More like 8-10oz per 5 gallons.

The car is a 2000 Impreza 2.2L. Basia

Just look at it analytically.. At 10 oz per 5 gallons you are running a 64:1 fuel-oik mix - pretty close to a standard 2 stroke mix - and at 20MPG and 2000 miles on a change, you are using 100 gallons of gas and over a gallon and a half of MMO. Also, running a 60:1 ish mix will make the engine smoke, and for the converter to "convert" that smoke, the converter would only last a few tanks of gas before it suffered severely reduced efficiency. Frankly, I don't believe you run that much MMO in your car, and if you do, I fail to even begin to understand why you would want to. Not like you are running a Wankel. If you are, and if you are experiencing a "steady albeit small" rise in oil level,- it would be a VERY small increase - you would be so much farther ahead on ALL fronts to simply add the oil required to the crankcase. IF any appreciable amount is getting past your rings they are badly worn And MMO is pretty close to a 5W weight oil - closer to 5 than 0.

During the time I had other cars(I drove company car for 40 years), either company car or my own(always Acura/Honda) I never experienced such oil consumption. In particular Acura engines never needed oil top up between oil change per service reminder on dash MID. Son who still drives WRX says on his synthetic oil, he has to top up between oil change intervals. When I Googled this issue, more that 1000 people complained about this and there class action suit is outstanding against SOA. Also this CVT business, I can't get used to the rumbling noise when engine is cold like first thing in the morning. That was it, I went out and got rid of Forester XT for an Acura RDX with Tech option. Kids can drive Subaru but I'm not sure of myself. I explained to wife why I am switching to different car all of sudden. Anyhow wife has her own car. Only on week ends we drive in my car. Good luck to folks who own late model Subaru vehicles. My short observation, oil seems to be burning. I don't know if it's blow by or due to the engine design.

I just give up on the vehicle. Subaru or some experts better come up with good logical explanation soon. Bye to Subaru, back to comfy and familiar cockpit of Acura.

I do use a lot of Marvel and have empirical proof not theoretical analyticics, to back what I am saying, the distick does not lie.

I use MMO mainly beacause I drive through Sierra Nevada mountains at high rpm's high speed, and it helps the engine a lot. Runs smoother, saves gas, keeps engine rings clean. I started using it in a 2.8 V6 Chevy, at around 75k miles. Initially small amounts, then as the car got older more.

On my 2000 Impreza L 2.2L I have used MMO since new. Only in gas, never in crankcase.

Initially, about 4-5 ounces per 5 gallons, until about

80k miles, than doubled the dosage.

I know the stuff makes it past the rings as the oil on the dipstick slowly rises over the approx. 3000 mile OCI. When its time to dump the old oil I always have a slight overfill, half a centimeter or bit more.

I always try to fill new oil to the maximum line on the dipstick or a touch below, and its the same thing by 3000 miles, a slight overfill. I,ve owned the car for 112k miles and always change oil myself. There is nothing wrong with the rings, they are not worn at all, as a matter of fact in very good shape. Car has excellent compression, for its age and milage fantastic.

The fact is MMO makes it past the rings in small amounts. It does not hurt the catalytic converter either I pass emission tests no problem, just remember not to put any Marvel into tank before going for testing.

Basia

ps. my experience led my to suggest Marvel in gas as a way to steady and somewhat help replenish oil in a Subaru that consumes oil. I have no idea whether it would work, or how much. My experience suggests it could (?).

I just went to the garage with a large 60cc syringe to measure precisely the amount I've been pouring into the filler neck of the car. The filler neck holds about 70cc of fluid, and I've ben pouring

2 filler necks full per 10 gallon of gas,

...so it comes to about 5oz of marvel per

10 US gallons of gas. This is the more or less precise amount poured over about 80k miles.

Since 80k I've been adding more, about 4 filler necks per 10 gallons of gas. Comes to about 10oz per 10 gallons.

About half centimeter maybe a tiny bit more over 3000 miles is what I have observed. Marvel is thin, maybe 5w maybe 0w, it is thin.

As I said I like using it a lot. The oil gets dirty with use fast, but that nmeasns it is cleaning the innards which is good. Marvel suggests using 4oz per 10 Gallons so I am currently using more than twice as much. Using more than recommended is said to be a waste but not detrimental, just a waste.

I found it to work very well especially with high speed high rpm driving. I add to 91 octane gas. It kills octane.

Basia

Using a small amount of MMO in the fuel acts as a "top end lub" which can extend the life of an engine. Using more than enough is wastedull, kills the octane (as you know) and causes excessive hydrocarbon emissions - while potentially killing the cat. converter. There is no reason to increase the amount of MMO added to the fuel of an older engine. Instead, just add some to the engine oil as well, so it can look after the oil control rings without having to go past the compression rings first. Using that combination will use LESS MMO to go a better job, without the potential to do harm - and without impacting emissions adversely.

I am a mechanic. Since 1969-ish