Oil Consumption - 2.0 TDI

[Preen59]

AFAIK the only way oil can get into the intake internals is by leaking from turbos, and I know that if it gets really bad the engine will "run away" by burning the oil.

Thats wrong.

The oil in the inlet is more likely from the crank case breather, and the reason, again, that you get this is from poorly sealing rings and/or labouring the engine.

You get blow by which intern gives you high crank case pressure, which vents to the inlet. Oil vapor condenses in the inlet tract, settles in places like the bottom of the intercooler.

[gldgti]

guys, i have to say, this is all getting a bit tired. i'd like to advise that participants in threads that degrade into taking pot shots at eachother or re-justifying OPINIONS be discontinued due to their content being of NO VALUE to the forum.

please, PLEASE refrain from adding volumes of worthless opinionated comments to the forum. its a waste of your time, and others.

furthermore, PLEASE DO engage in a healthy discussion of facts.

overall - this forum is here for us to share experience, and learn from one another. not to whine and complain about life, other people etc.

the diesel section is generally a useful section with good discussions and good information. lets all do our best to keep it that way.

rant over. thanks.

[gldgti]

I've been wondering for a while if the reason some TDI engines use a lot of oil is related to poor oil seals in the turbo. I've seen lots of photos of TDI intake manifolds that are really clogged up, and I thought that might be due to a mixture of oil and soot from EGR. I've also read of lots of reports of intercoolers and associated pipework literally dripping with engine oil (on the inside).

AFAIK the only way oil can get into the intake internals is by leaking from turbos, and I know that if it gets really bad the engine will "run away" by burning the oil.

I have read about large numbers of 4 cyl VAG TDIs turbos self-destructing over the last few years (the 2.0 TDI in the Skoda Octavia seems particularly prone according to the BRISKODA site). These failures seem to be bearing and oil related (rather than sticking vanes).

What do others think of this theory ?

as preeny stated, oil in the intake is most likely a consequence of crankcase ventilation gasses.

you are correct to assume that oil in the intake could be from leaking turbo seals, however this is incredibly unlikely with a diesel engine, since the intake tract between turbo and engine NEVER see's any vaccum (if it does, it is VERY small, like 1 in/hg.

one thing that is noteworthy, however, is that there is a complex relationship between different areas of the engine and the pressures they run at - specifically -

>under high load/boost, blowby gasses will pressurise the crankcase, and produce a heavily oil-laden air mixture into the intake

>also under high load/boost, the turbo oil drain is less effective, as the engine oil pressure feed through the turbo-bearings must then work AGAINST crankcase pressure. this makes the total pressure across the turbo intake and exhaust oil seals higher, and would result in more seal leakage, if it was occurring at all. however, this is unlikely to account for a large part of the intake tract oil

>an intercooled intake tract provides the perfect place for oil to separate from the intake air due to sudden pressure decrease/temperature decrease across the intercooler (dynamic scenario) and thus oil will accumulate here. i would go as far as to state that would be perfectly normal to find some oil in the intercooler of a turbocharged diesel engine.

having said all that, that amount of oil usage that is "normal" is a direct result of how well the piston rings have bedded in, and how the vehicle is driven. the Volkswagen TDI engine is not a "throw-away" engine - it is engineered for long service life with high mileage. because of this, components such as rings/pistons/cylinder bores are hard, expensive components, and take large service cycle time to wear in. an engine does not "run in" within 1000km.... or even 2000km. and it is normal, particularly in diesel engines, for characteristics such as oil usage and fuel consumption to take many tens of thousands of km to stabilise, depending heavily upon how the vehicle is used.

all of these points should be considered when assessing how much oil your engine is using.

[250 downunder]

I have a 2.0l TDI which I have only owned a short time, however during the 3,500 kms. covered since purchase it has used virtually no oil [current mileage is 21,500] so I can't chip in with any complaints about oil onsumption.
I would like to add a little about problems associated with crank case ventilation. I have an F250 with a 7.3l turbo charged, intercooled V8 and after some modifications it now runs up to 30 psi boost. At this boost level I encountered a problem with intercooler boots blowing off. I was horrified with the amount of oil that I found inside the tubes. Clamped silicon tubes and oil certainly don't mix. Initially I diverted the breather to the rear of the truck but found the foul smell and fuming unacceptable. Next move was to introduce the breather tube into the exhaust. I did this by welding a 3/4" tube into the exhaust [close to the rear] at an angle of 45 deg. with the end of the tube also cut at 45 deg. - looking for a venturi effect. I used a simple manometer to check for pressure at this point and found that I had a very slight vacuum over the entire rev range. The truck has since covered several thousand kilometers with no more blown intercooler boots and no doubt a more efficient intercooler.
Seems that a similar setup for the Golf could be a future project.

[gldgti]

I have a 2.0l TDI which I have only owned a short time, however during the 3,500 kms. covered since purchase it has used virtually no oil [current mileage is 21,500] so I can't chip in with any complaints about oil onsumption.
I would like to add a little about problems associated with crank case ventilation. I have an F250 with a 7.3l turbo charged, intercooled V8 and after some modifications it now runs up to 30 psi boost. At this boost level I encountered a problem with intercooler boots blowing off. I was horrified with the amount of oil that I found inside the tubes. Clamped silicon tubes and oil certainly don't mix. Initially I diverted the breather to the rear of the truck but found the foul smell and fuming unacceptable. Next move was to introduce the breather tube into the exhaust. I did this by welding a 3/4" tube into the exhaust [close to the rear] at an angle of 45 deg. with the end of the tube also cut at 45 deg. - looking for a venturi effect. I used a simple manometer to check for pressure at this point and found that I had a very slight vacuum over the entire rev range. The truck has since covered several thousand kilometers with no more blown intercooler boots and no doubt a more efficient intercooler.
Seems that a similar setup for the Golf could be a future project.

very interesting indeed - although i'd like to put it closer to the turbo (where its still nice and hot) to give it a chance to burn off.

i hear you on the intake pipes blowing off - i've only just managed to sort the piping in my mk3 to keep them from blowing off too - i've TIG'd big nobbly's around the ends of all the stainless pipes so that once the hose clamp is tight, it physically wont allow the silicone hose to slide off.

[250 downunder]

"although i'd like to put it closer to the turbo (where its still nice and hot) to give it a chance to burn off."

My concern with placing it in that area would be back pressure. The last thing you want is restriction in the CCV line. Engine oil seals could suffer with any increase in crankcase pressure.

[Oneofthegreats]

Prove to me that every other manufacturer accepts that using 1.0L/1000km of oil is normal. I'd love to see conclusive proof of this. First and foremost, GM did recalls on engines using that exact amount of oil. So obviously GM disagrees with you. Ford reckons if it uses any oil at all, go straight to the dealer because it shouldn't. That's two. Renault disagrees with you, that's three. I could keep naming manufacturers...

I live in 2008, not 1938. I shouldn't be worrying about my engine destroying itself because its doing something that its not supposed to do, because the factory accepts a major design fault and passes it off as "OK."

I look forward to your proof that it is otherwise.

How about this from a 10 year Senior Registered BMW tech. & BMW service bulletin

"Oil consumption should at the earliest be measured after a distance of 7500km, since the process of breaking in the engine will essentially only been completed after this distance & the oil consumption stabilized"

"BMW spark-ignition & diesel engine's, the maximum oil consumption is 1L/1000km.
Due to their higher power & engine speed level's, M-Power engines may have a maximum oil consumption of 1.5L/1000km"

I'm not speaking on every other manufacturer's behalf, but I would like to see some proof now of the oil consumption spec's of those manufacturer's please.

I don't believe for one second that they say "this engine will not use any oil" because that is crap! There has to be safety buffer.

[Oneofthegreats]

I think just about all VW dealer's provide a free oil level check & top up.

We even do driveway brake light globe replacement free of charge.

[Oneofthegreats]

This is for all the VW diesel owner's! ha ha

They just released a modified dipstick!

[THR]

Well I am at slightly over 8,000km (just did a trip from Sydney to Gold Coast return) and my 'low oil' light has come on.

I checked it before I left and thought it was low and called my dealer. They said not to worry unless the light came on... I was going to get a top up before I left but relied upon their advice.

Anyhow, the light came on just as I returned to Sydney and it's only done about 20km since. Which was quite fortunate - 2,000km+ and it at least made it back to Sydney.

How safe is it to drive on until it gets more oil (i.e. how far can it go)? I don't have the opportunity to get to the dealer until Friday afternoon / Saturday morning at the earliest. I checked the level and it's on 'minimum', so it does have some oil.

I imagine they'll charge me as well. I also had a blown left indicator; all in the space of a couple of weeks. Joy!

I don't think I'll do an oil change now, just top it up, as it's due for a service in February.