Do we know the cause of 3.0RB oil burning yet?

[chiangstar]

Hey Guys,

First Post! I current drive a MY05 Liberty 3.0R-B and will be upgrading to an MY09 3.0R-B in the next week or so. I remember there being quite a serious issue with oil burning on these models on the earlier cars. Is the burning still as prevalent on the later Gen 4 models? I am getting conflicted reports from other forums and from some posts on this forum also. Also read something about engine breaking causing a few things that ends up in burning ...

I actually dont mind checking and topping up oil from time to time and know that boxers generally do burn a bit of oil...

Has any one pinpointed whether this is random or something to do with the breaking in process, etc? I didnt have any serious problems with my MY05 so I'm just going to do the same thing with the new one... but it would be handy to know if I should be doing any thing in particular.

Thanks

Simon

[Ric]

What I was told when they replaced my engine under warranty was, under high vacuum (i.e. backing off at high revs), the oil was being sucked around the rings.
You don't get so much engine braking with an auto gearbox so it doesn't happen nearly as much as in a manual.
The later engines had revised pistons and rings, with the rings at a greater angle, which is supposed to be better at holding back the oil.

It was also suggested that the running in of the engine could affect how bad this was.
I was told to drive it hard for the first 100km after the replacement engine was installed, and avoid engine braking as much as possible during this period.

[chiangstar]

The later engines had revised pistons and rings, with the rings at a greater angle, which is supposed to be better at holding back the oil.

HA! "supposed" to be better at holding back the oil i guess i'll find out soon... im upgrading to an MY09 today so soon enough i'll be able to see whether theres any difference. I engine break quite a bit...its one of the joys of a manual car! Having said that my oil issues were far from catastrophic with my MY05

Have you heard anything about different weight oils making a difference? i started to do this experiment but now im trading my car...

Simon

[Woodduck]

I have a MY06 and I honestly dont notice it. Between services it might drop 500ml but it never drops enough for me to have to top up in between services? Maybe my car was "broken in" well lol.

[Ric]

Anything below one litre consumed per 2,000km travelled is considered acceptable by Subaru.
Note, on a 12,500 km service interval, that is just over 6 litres, i.e. more than the sump capacity!

[teK--]

When I used to work at Holden I thought it was ridiculous that their acceptable spec was the following:

3.8L V6: 1.5L/10,000Kms
5.7L V8: 2.5L/10,000Kms
3.5L V6 (light commercial): 3.5L/10,000Kms!

I thought Subaru's specs would have been tighter than that.

[Ric]

Actually, "acceptable" may be lower. Over 1 litre per 2,000 km is their "we'll consider swapping the engine under warranty" threshold.

[chiangstar]

I have a MY06 and I honestly dont notice it. Between services it might drop 500ml but it never drops enough for me to have to top up in between services? Maybe my car was "broken in" well lol.

Do you do much higher speed engine braking, Woodduck? From your other thread I'm guessing you'd prefer to have a bit of oil burning than what you're experiencing

Simon

[Woodduck]

Yeah i do quite a bit of high speed engine braking actually. Living in a rural area you quite often get stop signs in 100km zones and shit like that. Plus, the open twisty roads cause you to drive spiritedly on occasions

But yes. Would much prefer to top up the oil every now and then than not know if my car will make it home every time i drive it haha.

[Ric]

I drove 3,000 km around country roads in South Australia just before my engine change, and it didn't use a drop.
The moment I got back to city stop-start traffic, it started drinking oil again.

[chiangstar]

That's interesting... so it doesnt seem to be as prevalent with highway driving even with the use of high speed engine braking, but it is bad with city stop/start driving with or without engine braking...

so its not necessarily the engine braking at all... it could be stop/start driving that does it... but if thats the case then why do the manual cars suffer more than the autos given that engine braking is more particular to manuals... hmmmm what else is particular to manuals?

Probably way off track here...

Simon

[Ric]

That's interesting... so it doesnt seem to be as prevalent with highway driving even with the use of high speed engine breaking,

Well you don't do much engine braking when you're cruising at 100/110 on a highway, and doing a few hundred km each day.

(Note, it is "braking", not "breaking". It refers to using engine compression to slow the car, instead of using the brakes.)

but it is bad with city stop/start driving with or without engine breaking...

well for me, half of that driving is crawling along the monash freeway, where I avoid touching the brakes in slow traffic, just back off and use engine braking to slow down until I must brake.

[chiangstar]

(Note, it is "braking", not "breaking". It refers to using engine compression to slow the car, instead of using the brakes.)

LOL my bad... i understand what engine braking is and I use it often... I just had a brain snap with spelling ... edited my post to correct my bogan spelling...cheers

Woodduck was saying that even though he drives mostly in rural areas, he uses engine braking regularly and doesnt experience much oil burn

well for me, half of that driving is crawling along the monash freeway, where I avoid touching the brakes in slow traffic, just back off and use engine braking to slow down until I must brake.

We have similar driving styles in that situation... I try and use highways for more free flowing traffic whenever I can, but am often stuck in slower Sydney traffic using the same driving / braking techniques...

Would it make sense that higher speed engine braking would create the most significant 'vacuum' conditions as opposed to lower speed engine braking?

Simon

[specbtommy]

i noticed my oil going through really quickly. thought it was just my car.

[Blaeven]

my ez30 is actually leaking oil (leaving little puddles) and still uses less oil than some of you guys... lol

i think i have a leak from the back of the passenger side head