Hi. My navara has done 140k. When I accelerate hard around 3000-4000rpm a lot of black smoke poors out. Any ideas on what it could be?
Black smoke when accelerating hard
bmlocock86
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Hi. My navara has done 140k. When I accelerate hard around 3000-4000rpm a lot of black smoke poors out. Any ideas on what it could be?
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Huh? Oil burners?
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Thanks mate I realise diesels "oil burners" blow smoke when they r booted but mine is just a little bit excessive. Yeh I was thinkin injectors but took off the inlet pipes and it looks like I have blown a turbo oil seal. Is that common in this model?
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I've just been told about the blow off valve leaking oil back into the intake pipes because I have a dp chip and it cause more blow-by than usual. Anyone else have this problem?
Only ones that are badly tuned, low on boost or badly maintained (i.e. blocked air cleaner) do.JasonE said:
New engines run so clean the exhausts stay shiney on the inside.
First step in solving a smoke problem is air, when was the air-cleaner element last changed? Pull the MAF and clean that too.
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Oil found inside intake parts don’t mean something is wrong and it is quite common to find.
Usually, excessive black smoke in turbo diesel engines is due to air leak from intake hoses between turbocharger and manifold.
Next thing is the injectors.
If air filter is good, look for cuts in one of the turbo hoses or for leaky intercooler, if you will find a lot of oil at one of these parts that's mean there is an air leak.
Usually, excessive black smoke in turbo diesel engines is due to air leak from intake hoses between turbocharger and manifold.
Next thing is the injectors.
If air filter is good, look for cuts in one of the turbo hoses or for leaky intercooler, if you will find a lot of oil at one of these parts that's mean there is an air leak.
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Oil in the intake passages comes manly from the turbocharger and from PCV due to high blow-by while boosting, together with EGR gases it becomes sludge that clogs inlet ports.
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Every turbocharger discharge small amount of engine oil while operating, this is part of the lubricating and sealing performance of the turbocharger shaft and collars.Kiwibacon said:
Oil also found in turbocharger inlet hose towards the air filter direction and this also oil mostly comes from the turbocharger and happens because positive inlet pressure exists in some engine conditions.
This is the main reason why turbocharged engines have higher oil consumption than atmospheric engines.
I disagree.GreaseDonkey said:
Turbo seals leak inwards, not outwards. They rely on the pressure being higher in the compressor and turbine housings than in the bearing core (which is vented to the crankcase). Hence the seals always pass an amount of boost and exhaust through the seals, through the drain and into the engine to be expelled out the breather.
Turbo diesels run positive compressor and turbine pressures all the time.
Only when crankcase pressure gets too high (i.e. blocked breather or worn/broken piston rings) will the turbo will then start venting oil through it's seals into the intake and exhaust, this is immediately obvious as you're followed by a cloud of blue smoke.
Petrols with a suck-through carby setup are the exception as they pull a vacuum on the compressor side, they need a carbon face seal to stop oil getting out.
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Air should never enter the turbocharger bearing housing and that is the main purpose of the seals. If air will get inside it will cause lubrication problems to the turbocharger bearing and even high engine blow-by.
The seal are actually very similar by design intend as the piston rings in the engine, they need some oil to pass through them for sealing and lubrication.
Try to remove the breather from the inlet hose and let it vent to the atmosphere and then check if the hoses and intercooler are remaining dry from oil…Did that already, they are not.
The seal are actually very similar by design intend as the piston rings in the engine, they need some oil to pass through them for sealing and lubrication.
Try to remove the breather from the inlet hose and let it vent to the atmosphere and then check if the hoses and intercooler are remaining dry from oil…Did that already, they are not.
Air does flow in and it does add to engine blowby. The ring seals are there to minimise the flow, not stop it.GreaseDonkey said:
Think about it, 20psi in the compressor housing, 30psi in the turbine housing, 0.1psi in the centre housing. Which direction do you think the flow will take?
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You got the facts wrong. Jurnal bearing inside turbocharger have to have sufficient oil pressure to sustain hydrodynamic lubrication so oil pressure feeding the turbo is usually as oil system pressure.
At the compressor housing and especially behind the compressor wheel pressure can go negative in some engine conditions (mostly at low engine speed). Also I know that the compressor and turbine wheel design is to enhance turbulence at the seal area to help oil or air flow to the other side but some oil is flowing from core housing and this gives good and bad affects. Good - improving seals lubrication. Bad – oil consumption and carbon buildups.
If you got turbocharged vehicle I can suggest that you run it with no hoses attached to the turbo and let the engine run just above idle speed (1000-1500 rpm) for more than 10 minutes and watch the oil leak comes from turbo seal.
At the compressor housing and especially behind the compressor wheel pressure can go negative in some engine conditions (mostly at low engine speed). Also I know that the compressor and turbine wheel design is to enhance turbulence at the seal area to help oil or air flow to the other side but some oil is flowing from core housing and this gives good and bad affects. Good - improving seals lubrication. Bad – oil consumption and carbon buildups.
If you got turbocharged vehicle I can suggest that you run it with no hoses attached to the turbo and let the engine run just above idle speed (1000-1500 rpm) for more than 10 minutes and watch the oil leak comes from turbo seal.
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