[Redrock]

Bought a 2010 Forester Premium 5MT in Dec. 09. This is my first Subaru and maybe my last. I currently have 12,600 mi. on it.

First problem:
Once the weather got warmer and opened the windows, I started noticing an engine knock when shifting and on occasion when climbing. The manual says this is rare, but this happens many times a day. Dealer said to switch to 89 octane. Did this and it happens less frequently, but it still happens. Dealer then said to switch to 93 octane. Haven't done this yet - but, I bought a car thinking I would be using 87 octane. The increased cost for gas is really making me angry! Contacted Subaru of America and they also said to switch to higher octane and was told my problem was "just outside of normal" - whatever that means.

Second problem: Oil consumption. Dealer started an oil consumption test as I noticed increased oil use. First 500 miles, no oil consumption. Next 1200 mi. it used a half quart. I was told by the dealer this is normal. I have a call in to S of A on this one, but they have not gotten back to me yet. I've never had a new car that used so much oil.

Are they just giving me a line of bull that all this is normal? Could the two problems be related? In July I am headed out on a 6000 mi. trip and I'm really starting to worry about all of this. For what it's worth, I drive like a little old lady and I shift at the recommended speeds. HELP!!

 

[flstffxe]

For what it's worth, I drive like a little old lady and I shift at the recommended speeds. HELP!!

This may be causing some of the issues you are seeing/hearing.

As for the ignition knock raise the RPM you shift at up a little bit more. Get into the upper mid range of the power band for a while and see if there is any change. The NA 2.5L has an build recipe that is more like a slightly worked over American V8 then a Japaneses 4 cylinder.

Your typical Japaneses 4 cylinder has a very has a small bore and a small stroke(say 80mm B x 80mm S) which is a very for giving engine. It just wont produce any power below given RPM range, to high of gear going up hill you just slow down until the engine stalls with out much feedback from the engine.

The typical American V8 has a much larger bore( I'll use a typical Chev 350 for comparison). 4'(101.6mm) bore x 3.48"(88.39200mm). By comparison the Subaru has a 99.5mm bore x 79mm stroke. Like the slightly worked over V8 in my example here the Subaru has a compression ratio of 10:1. As with most high performance V8s around 10:1 they will start talking back to you in the form of ping/knock if worked too hard at too low of a RPM, they need to be brought up into their power band to be happy, unlike the Japaneses 4 cylinder though the V8 will try to power through it. The higher the compression, the bigger the bore, the smaller the stroke and the fewer the cylinders the more the engine will talk back to you and the more critical being at the proper RPM becomes. By comparison the Subaru has a bore that is almost as big, a compression ratio that is the same and a stroke that is smaller, along with fewer cylinders. Like the V8 the Subaru will talk back to you if you are in the pushing it to hard at to low of RPM, the catch here is the Subaru has 1/2 the cylinders so it will talk back to you a tad more but will still try to power though it.

The whole point of all that above is that these engines are not your typical Japaneses 4 cylinder they are more appropriately compared to a big American V8 with work done to it that would be classified as a high performance engine. They need to be run where they are happy, which may not coincide with your thoughts on where they should be run.

As for the oil consumption. The way I read your post is at 1700 miles you are seeing 1/2qt of oil consumption. Nothing to worry about, It will probably shock you but most auto manufactures including Subaru now consider 1qt of use for every 1000 miles to be normal, I think that is high but...Some of it due to the boxer engine lay out, the cylinder wall are laying horizontal versus vertical like just about every other engine. This allows oil to sit in the cylinder until the piston travels down to push the oil out. The boxer doesn't get the added help of gravity to pull the oil out of the cylinder.

You can try different oil brands while tracking the consumption to find one that your engine is happy with. Some Subaru engines will consume one brand like water down the drain while other brands seem to stick around forever.

 

[Tuned200]

1st off, welcome to the forum.

I have a couple questions reguarding your car.

Was the proper break in procedure followed?
How often do you have the oil changed?

The car is set to run on 87, and the dealer telling you to up it to 89 and 93 is horse crap. While I would perfer you to sort it out with your dealer, making the call to SOA seems like the correct thing to do.

 

[rsay777]

and what method are you using to determine oil consumption?

Draining and measuring?

Dipstick level monitoring? not very accurate.

 

[Tuned200]

good thinking. a lot of variables with dipstick filling

 

[flstffxe]

1st off, welcome to the forum.

I have a couple questions regarding your car.

Was the proper break in procedure followed?
How often do you have the oil changed?

The car is set to run on 87, and the dealer telling you to up it to 89 and 93 is horse crap. While I would prefer you to sort it out with your dealer, making the call to SOA seems like the correct thing to do.

I completely agree Tuned200. But to the OP, don't be surprised to come to a dead end with the ping/knock issue with SOA/dealer. My point from working in shops, I all to often hear/have heard "my bike/car pings, there must be some thing wrong with the engine, it's not me I drive like a grandma........".

More often then not the shop can only recreate the issue when the vehicle is driven improperly(lugged, too low of RPM for the load). In these cases a you could run 100/110 octane in a engine designed to run on 87 and you may still get ping/knock.

Other cases it seems to be the customer uses the same gas station for fuel(regardless of grade) and always seems to have a issue even when driven properly. Many times switching stations(brands of fuel) can take care of it.

There are other knocks you may be hearing to tat are normal for a Subaru and the MT. Subaru boxers are not always the quietest of engines. They can have some internal noises that sound like they would be concerning in any other engine. I have also seen/heard throwout bearings on the 5MT rattle around sounding like a engine knock only when at certain RPMs, they would go away as soon as light pressure was applied to the clutch. It may be normal, or it may not. However as Tuned200 said there is no need to run any thing other then 87, unless the 87 in your area is really poor quality.

and what method are you using to determine oil consumption?

Draining and measuring?

Dipstick level monitoring? not very accurate.

I some what agree, It may not tell you the amount in the engine but it can be used to monitor the difference from when it was filled(initial level on the dip-stick) and there fore tell you know how much you have added(via your oil bottle) to bring it back up to that same initial level.

 

[trailangel]

I have the same car. I was burning a bit of oil.. about 3/4 qt. on a 2,000 mile trip.....next 2k trip to Portland and back...burned less oil. (Chevron Supreme 5W30 dino) That was at about 12K miles. I think it's just getting broken in at these miles. Some oil burning when new is normal. And yes.. you have to wind the little motor up and it will be happy.:icon_biggrin:

 

[Redrock]

First, thanks for all the input! Second, I will try to answer all of your questions.

"I drive like a little old lady" = I do the speed limit, ie, not over 65mph most of the time. I do a lot of highway miles, much more so than city driving.

I have been shifting at the recommended RPM's as noted in the manual.

The dealer is doing the oil consumption test apparently according to SOA specifications. They changed the oil and showed me the dip stick. It was on full. This was at about 11,000 mi. I drove it to 11,500 mi. and they had me bring it in and they looked at the dip stick, it was still on full. I went another 1100 mi. and brought it in again. It was down a half quart. I witnessed all of this.

I followed the break in procedure as noted in the manual and have had the oil changed about every 3000 mi. at the dealership. The manual says much less often but I can't bring myself to do it that infrequently.

The dealer had a mechanic come with me while I drove the car to hear the knock. He therefore witnessed how I drive it. His recommendation was to up the octane. As I travel a lot for work, I fill up at various different gas stations, using different brands. Since I started to use the 89, the knock frequency has decreased but it is not gone. It seems to happen mostly from start up and then from first to second. On occasion it will knock when climbing an incline, and I have never noticed it on a hill.

As I said, this is my first Subaru and I REALLY like it, except these two issues have me wondering. I've had Toyotas and Hondas all driven in excess of 200,000 mi. each, all manual transmissions, and never had these kinds of problems. In fact, never had any problems.

Thanks again.

 

[flstffxe]

If you are using these as your recommended speeds:

Shift up mph (km/h)
1st to 2nd 15 (24)
2nd to 3rd 25 (40)
3rd to 4th 35 (57)
4th to 5th 45 (73)

Try adding 5-8 MPH to those speeds, doesn't mean you have to lay into the throttle to do it just let it wind out just a little more. As the manual also says those speeds are a,

best compromise between fuel economy and vehicle performance

The ping/knock is detrimental to both MPG and performance, it is also the first warning sign of lugging an engine

 

[Redrock]

Thanks. I have just begun to do this so we'll see if it makes a difference.

For what it's worth, I've been getting between 27 and 29 mpg combined in the warmer weather, but mostly either highway (65mph) or local roads (45-50 mph). I've also gotten as high as 31, but that has not happened often.

 

[Redrock]

Another question: Does anyone think switching to synthetic would help?

 

[crewzer]

Redrock,

Sorry to hear about your car engine's pinging problem. Modern engines contain knock sensors that the ECU uses to retard ignition at the onset of pinging/engine knock. While occasional mild pinging may be OK, regular and repeatable pinging is not, IMHO.

Here are relevant comments from the '09 owner's manual (page 7-2 and -14):

The 2.5-liter non-turbo engine is designed to operate using unleaded gasoline with an octane rating of 87 AKI or higher.

...

Do not be concerned if your vehicle sometimes knocks lightly when you drive up a hill or when you accelerate. See your dealer or a qualified service technician if you use a fuel with the specified octane rating and your vehicle knocks heavily or persistently.

...

The engine may, on rare occasions, knock when the vehicle rapidly accelerates or rapidly pulls away from a standstill. This phenomenon is not an indication of a problem in your vehicle.

Dealer/SOA suggestions to use >87 AKI fuel to "cure" regular and persistent pinging aren't acceptable, in my view. Instead, the dealer should replace the knock sensor(s) and reset the ECU.

I've driven my Forester (see signature) over much of the country (hot, cold, sea level, high-altitude, A/C on, A/C off, lightly loaded, fully loaded, different gas brands, different AKI's, etc.) with zero knock/ping issues. I generally use 87 AKI fuel in the winter, and 88-89 AKI fuel in the summer. My higher summer AKI fuel use is a personal preference and is not knock-related.

On the other hand, your Subaru's engine will make noises that you probably never experienced in your Hondas or Toyotas. Specifically, the engine makes a "burbling" sound when it's cruising along under light-to-moderate load. It's a normal characteristic of H-4 motors, and I, like many Subaru owners, find it somewhat endearing.

HTH, and best of luck!
Jim / crewzer

 

[Redrock]

Thanks for your reply, crewzer. For the not so mechanically inclined, what is the "ECU"? Also, I will be making a similar trip out west from Massachusetts to Colorado and then on to Utah in early to mid-July. This is part of the reason for getting some of this stuff resolved sooner rather than later.

 

[craigbhp]

First, thanks for all the input! Second, I will try to answer all of your questions.

"I drive like a little old lady" = I do the speed limit, ie, not over 65mph most of the time. I do a lot of highway miles, much more so than city driving.

If you drive like a little old lady you could have substantial carbon build up on the pistons and combustion cambers that could cause pinging. Top end cleaner could cure your problems

 

[crewzer]

ECU = Engine Control Unit, or engine control module (ECM). I hope you get the car problem(s) sorted out and then have a wonderful trip.

Best of luck!
Jim / crewzer