OT - does your turbo idle rough(ish)?

[Veloo]

Sorry for the OT but feeling a bit stuck on this one.

So my 2013 Subaru Impreza engine is being "rebuilt".
My coolant level was low and they suspected an "internal leak" since rad and hoses passed a pressure test.

I was supposed to get a rebuilt short engine block but turns out I'm getting a new block as well as a new head since the original didn't pass inspection/ test. All other internals are being reused.

So they reassembled and reinstalled on Tuesday night and took it out for a road test yesterday. They said it drives fine but idles rough. I reminded them that I did bring that up in the past that I found the original engine had a rough idle and even sputtered a number of times when stopped at lights. The tech told me that the new engine idled like a turbo engine - implying that they do idle slightly rougher than a regular boxer engine. So they pulled the engine back out and further analysis showed one side was taking in a bit more air than the other. He described the condition as "lean".

I'm not a car guy and I've never driven a turbo anything.

Can any turbo drivers comment on the claim of a slightly rougher idle?
I'm not sure if he meant only Subaru boxer turbos idle rougher or turbos in general.

[stien]

Have driven turbo cars, rough idle isn't something I'd say is normal. Shouldn't skip or anything if it's running correctly. Make sure they fix it all.

Also I hope they're covering all these rebuilds. I'm sure you know about the class action lawsuit pertaining to the 2014+ models. I sold mine because it went through oil like crazy. Another discussion for another thread I suppose.

[bikerboy337]

my saab 9-3 aero idled smooth as can be, that was a v6 with a turbo thrown in... only turbo i've driven...

wish i still had that car, was so much fun to drive...

[Veloo]

Yup, all under warranty.
I was burning oil too but they fixed that about a year ago.

[FlashUNC]

The rough thing isn't a condition of a turbo or boxer engine. My GTI doesn't have a rough idle at all despite being a turbo car. Though it does have that characteristic tick of a DI motor.

If one side is running lean, there's a problem somewhere.

Course, with a new block and head, the question is did they reassemble everything properly, or fail to address an issue separate from what was causing the rough idle.

Its a turbo'd boxer motor, not a tractor. Even though it sounds like one.

[christian]

Sorry for your trouble. I don't find that turbos necessarily idle lumpier than naturally aspirated engines on balance, but I do think that Subaru boxer fours are pretty lumpy at idle. Have you compared it to another Impreza? Is your engine a turbo, or they're just saying it idles like a turbo. If it's the latter, that doesn't mean anything.

To me, it sounds like an injector problem or an ECU problem.

What was the root cause of the coolant leak? Head gasket?

[benb]

I love my Subaru to death (Outback 2.5 no turbo) but these stories are always a bit frightening. I'm always paranoid about oil burning issues as the new Subaru engines seem to have had trouble with that too.

[El Chaba]

Subarus seem to be fabulous and bulletproof....or problematic and unfixable. Fortunately the former far outnumbers the latter.

[Veloo]

Mine is not a turbo. It`s just one up from basic.
I do agree the boxer does seem lumpier`. I`ve listened to other Subaru boxer engines and they are not as quiet as I thought mine was supposed to be. I have a 2014 Impreza as the loaner and it`s smoother and quieter than my original engine but not as quiet as I thought it would be.

Interesting that my neighbour who does have a turbo Impreza said his does idle rough.

This all started when I was getting cool and cold air blowing from the vents. I checked the coolant and found it to be below the LOW mark and also low in the rad. I brought it in and they said rad and hoses were fine so they suspected an internal leak in the engine. They never said anything about the head gasket.

Yes, someone`s gotta be the statistic and that`s me.

[GScot]

Shouldn't sound any different than the non turbo version at idle. And lean is bad, especially for a turbo engine. Lean is what leads to burned pistons and another engine.

[FlashUNC]

A new block and head implies something was seriously wrong, well beyond just a blown head gasket.

[christian]

FlashUNC: New block and head would seem to indicate a casting problem with the water jacket internally or something like that, allowing coolant to seep into the sump. With the escape of the coolant, the thing ran hot, and the head warped.

I don't think the lumpy idle is necessarily indicative of anything, unless it's very bad. If the readings from the Mass airflow sensor (MAF) and oxygen sensors indicate that the air-fuel mixture is correct, then it's ok.

[soulspinner]

I love my Subaru to death (Outback 2.5 no turbo) but these stories are always a bit frightening. I'm always paranoid about oil burning issues as the new Subaru engines seem to have had trouble with that too.

Ive seen oil burning issues with all types of new cars. Porsches , Volvos, Toyoas, Subies, and more. To me we have reched the point where oil is so good (slippery) that its creating other issues. Meanwhile my 2004 yota with 165000 miles gets fresh 5-30 conventional oil every 3750 miles and it uses none and even stays clean between changes.

[Don49]

My Subaru WRX (turbo) is smooth at idle.

[donevwil]

Have you checked/cleaned or replaced your fuel injectors ?

I had a 4cyl turbo that had a balancing shaft. Idled smooth as silk until 120k when it started to idle rough. Did the usual things (FI cleaner, different gas, etc) and nothing helped. The roughness ultimately became very occasional stalling so I did a compression test. Yep, one cy. low, not mandatory rebuild low, but on the edge. I figured a rebuild was in my near future, until my mechanic recommended a professional pressurized fuel injection/intake clean that required a special system (I forget the name of the system or process) that only one shop in town had. Took it in and $120 later smooth as silk.

[shovelhd]

Definitely not normal. Head and block replacement suggests overheating (low coolant), head gasket, and warping of the mating surfaces. Your work order should describe it.

The first thing I thought of is an intake leak. This is an opposed four, right, so it's possible two cylinders are running lean from the leak, causing a rough idle.

[witcombusa]

A little more info would be very useful if you want more accurate feedback.
Let's start with what year, model and mileage is your car?

For reference I have a '10 WRX w/65k on it. Now the '09 through to the new model were VERY lean at and off idle, to the point that a smooth launch was a problem. I actually did a few mods and reprogramed the ECU the second week I owned the car. Now it runs like it should have from the dealer (OK, maybe it runs a tad stronger (265hp @ wheels), but I'm just talking drivability here.

It idles dead smooth, cold or @ operating temp. SOMETHING is wrong if your stock engine does not. Did they show you the results of a compression or cylinder leakdown test? Please give us more info on the car.

[Ken Robb]

Sorry for your trouble. I don't find that turbos necessarily idle lumpier than naturally aspirated engines on balance, but I do think that Subaru boxer fours are pretty lumpy at idle. Have you compared it to another Impreza? Is your engine a turbo, or they're just saying it idles like a turbo. If it's the latter, that doesn't mean anything.

To me, it sounds like an injector problem or an ECU problem.

What was the root cause of the coolant leak? Head gasket?

I agree. My MINI Turbo idles very well. I assume that it is possible for a Subie turbo to idle well too. Maybe you have a slight air leak in the intake tract on one bank?

[denapista]

Laughing over here about rough idle with a turbo...

My Audi A4 wagon idle's like a damn 18 wheeler. Partially due to the transmission in the 2006 (B7) Audi cars. Torque converter was garbage, so you feel the vibration when in gear. If I idle the car in Neutral, it's smoother but still noticeable. I have a love hate relationship with My Audi Wagon. I swear this is the last time I want to buy an Audi, but the S4 appeals to me.

[oldpotatoe]

I love my Subaru to death (Outback 2.5 no turbo) but these stories are always a bit frightening. I'm always paranoid about oil burning issues as the new Subaru engines seem to have had trouble with that too.

Friend of mine, with a 2013, he's second owner, about 25k, is getting a new engine because of this. I'd be a little concerned about the dealer mechanics doing this tho.

[Veloo]

It's a 2013 Touring model wagon which is one level up from basic.
Has about 42000 km on it so on the low end of the spectrum for usage. Bought it new at the end of Dec 2012. I'd say 85 - 90% of those kilometers are city driving which is down town Toronto so very start and stop.
I average about 12 liters per 100 km which is pretty bad but since the loaner I have is showing about the same, I'd say that's normal for my kind of driving.

I know this is a lemon and I'm kind of OK being a statistic as long as the effort is made to rectify. Maybe I wasn't meant to have an Impreza - the car I was interested in since 1997 but opted for a Honda Civic. Here are a couple reasons why:

When I got it home just 15 minutes of owning it, I chipped the paint on the trunk cuz I slammed it shut not knowing the gate was ajar and the trunk hit the gate latch. Went back for touch up paint. Bad omen from the start?

Something (mouse, squirrel?) chewed through the right rear wheel sensor. Twice. First time it also chewed a hole in the rear seat so it could make itself a nice foam nest underneath. Never did catch the critter. First sensor was under warranty. 2nd one they figured out the cause so I paid.

As for other issues that have all been covered under warranty in the 3 years of owning:

- oil light came on within the first 6 months - they fixed the burning oil problem by replacing piston rings I think
- rear trunk cover broke and would retract by itself
- driver seat heating element has blown twice
- always felt the engine was noisy and idled rough. It even sputtered a number of times when stopped at lights. This is my actual car in this vid.
https://www.youtube.com/watch?v=IDOQzrSlhO4
- I find the brakes are not as sensitive as I'd like - ie slow respnse time - but the dealer and others have said Subarus are like that
- my battery died a couple months ago and I got a boost. Battery was fine and the dealer claimed my city driving wasn't right for properly charging the battery. I should drive once a month at highway speed for 1/2 hour to give it a good charge. Never happened on any of my other cars. I bought a battery tender instead.
- was getting random mix of cold/cool/warm/hot/very hot air blowing from the vent - turned out to be very low coolant levels which led to this engine being replaced cuz the rad and hoses passed pressure tests so they said they suspect an internal leak.
I never check my coolant and never did in m other cars. Most people told me they never had to either. A small number of other people said they do check and top up now and then.

Originally they said I only needed the short block replaced. Was supposed to be a rebuilt unit but ended up being new. Then they said I was getting a new head cuz the original wasn't passing. They were gonna reuse internal guts. Now they said they ordered a few other new parts so not gonna get the car back til Tues at the earliest since today is a holiday.

So yup... a lemon. Still paying for it too.

[GScot]

That does sound like a lemon. With some bad luck thrown on for good measure.

[Neil]

Shouldn't sound any different than the non turbo version at idle. And lean is bad, especially for a turbo engine. Lean is what leads to burned pistons and another engine.

This man speaks truth. I'm debating fitting a methanol injection system just to up the octane partially to remove the possibility of going lean under high boost.

Lean+turbo=$$$$$.