Oil Problem, 2.2 Puma

[rebuilder86]

well im not certain, but yoru post encouraged me to think more logically about my problem, i was considering that perhaps the head was cracked and inlet manifold pressure was perhaps being vented into the rocker cover and therefor into the sump, but it seems more likely that it would actaully be elsewhere, as a crack in the intake would most likely mean oil into the intake aswell which would mean blue smoke, but we are not seeing that. The onyl other place i can think of is the turbo oil return line being presurised.
SO yes, im suggesting it, but im certainly not certain, its a good theory though.
I cant seem to find any information online about this kind of occurance, only the opposite, that is, oil return line becoming blocked causing oil to enter the turbo. thats the only thing i can find any talk about on the web.

[Drake1793]

How can the return oil line by the turbo to the crankcase can be pressurized? Maybe by the cover valve? By pistons rings worn?
I removed and cleaned the line but I can't understand for what kind of reason can be possible to have that problem.

[rebuilder86]

because the turbocharger is an air compressor, and the oil lines are the first route of escaping air in the event of a failure of the bearing and/or seal inside the turbocharger.
It could be argued that the only place the air pressure realy increases is perpendicular to the vanes of the compressor wheel, and not behind the compressor wheel at the bearing but i think the entire region around the compressor increases in pressure.
I remeber not long ago, i had my intake pipe off the turbo and i could feel a lot of lateral freeplay on the compressor, indicating massive amounts of wear, so im thinking once that freeplay gets too large, air just starts getting past the bearing journals and ends up making its way into the oil line, but it cant fight the oil pressure from the positive line, so it exits the return line, and when doing this, it creates a lot of turbulence and oil mist and that is ejected out the top of the engine up through the oil drip holes in the cylinder head, creating even more oil vapour, and exiting out the PCV vents on the rocker cover, in my case, these vents are on the oil fller cap.
When my engine is running, oil mist is spraying out my oil filler cap. i havent seen what it looks lie when revving it, because i never have an assistant to push teh accelerator, its an electronicaly controlled injector pump, theres no way to rev it from the engien bay.
I know the rings are relitively fine, because im not getting any smoke at all, and with oil consumpton of 1L per 500 kms, shoudl be getting smoke out the exhaust if that oil was being burned in the combustion chamber.

Sorry not hijacking your thread, just telling you that i am now in your situation, and investigating the exact same thing.

[rebuilder86]

Looking at this cutaway of a turbo, you can see the blue area is where air is compressed, and it looks very plausible that the compressed air would also make its way to the bearing shaft, around teh green area, and that is wehre the oil return line is.
Bingo
Im quite certain thats what is happening, and i may be the first person to have ever discovered this, becasue i cannot find any documentation of this occurance on the net.

turbo cutaway.png

[rebuilder86]

In this diagram, they actually show you the oil seals, it is the one on the left near the compressor which i suspect has failed due to wear of the bearings and or shafts.
When that seal goes, is oil going to leak into the pressurized compressor chamber, or is the compressed air going to be pushing into the oil area.
I put it to you its the latter. why? because the oil is only under presure around the 2 journal areas, thne it is completely released of all pressure once it gets near the oil seals, unless of course the return line becomes clogged.
Perhasp just take the intake tube of your turbo, and wiggle the compressor wheel and see if yours has any freeplay. it should be perfectly stationary but rotate freely, and you shouldnt be able to push it in or out. If you can push it, then the thrust washer has failed, that is what has happened to mine i beleive.

turbo diagram.png

[Drake1793]

No movement in / out only a little bit up/down but the rotor don't touch the side wall.
Thank you for the explanation.

[Ken205]

Sorry drake but have you changed the rocker yet or not
Crankcase pressure in any engine is mainly caused by 3 things, cracked piston, worn piston rings or no breathing and
You have compression in all 4 cylinders
You could check the turbo by disconnecting the return pipe and blanking the block and drop the pipe into a bucket to see if the oil is pressurised when the engine is running but I still don't think that's your problem . If the turbo was pressurising the crankcase and your breathing system wasn't blocked it would leave out the pressure

[Drake1793]

Sorry drake but have you changed the rocker yet or not
Crankcase pressure in any engine is mainly caused by 3 things, cracked piston, worn piston rings or no breathing and
You have compression in all 4 cylinders
You could check the turbo by disconnecting the return pipe and blanking the block and drop the pipe into a bucket to see if the oil is pressurised when the engine is running but I still don't think that's your problem . If the turbo was pressurising the crankcase and your breathing system wasn't blocked it would leave out the pressure

I'm waiting for the parts.
The local auto-parts don't have them, so I bought on ebay.

[rebuilder86]

yeh of course it is a bit of a long shot, but the turbo is a common failure part, more common than the rings, especialy for a diesel with 176000.
THis particular quote form the first post is what is getting me focussed on the turbo.

"The turbo works fine at 2000rpm, between 1000 to 1500 there is a sort of on/off sound, The inlet manifold between the turbo and the intercooled was wet of oil but I don't know if the cause can be the vapourof oil from the valve cover."

[rebuilder86]

read this.
https://www.highpowermedia.com/blog/298 ... -oil-seals

Interestingly, this suggests that turbos require boost for the steel seal rings to actually do their jobs, which is probably why we see the oil mist coming out of the breather during idle, there is no boost in the turbo at these times to keep the rings pressed up against their seats and creat a good seal.
But then again, there is no real substantial pressure either, so it might cancel it out. ANyone knwo what sort of pressure is generated at idle in a 2.5 Turbo diesel?

Well i just disconnected my manifold from my turbo, and let it idle, and it still billows out smoke out the breather, so that kinda suggests the sump isnt being pressured by the compressor side, but it doesnt rule out the exhaust side. i cant think of any way to test that theory short of disconnecting the oil return line and capping the oil supply line. Thats too difficult.

[knobby1]

I'm suspecting a cracked piston on the "low compression" cylinder.

Lord Knobrot

[Drake1793]

I'm suspecting a cracked piston on the "low compression" cylinder.

Lord Knobrot

And with a cracked piston you do not see any kind of smoke on the exhaust?
I think the better way right now is to wait and change the parts ordered.

[knobby1]

I'm suspecting a cracked piston on the "low compression" cylinder.

Lord Knobrot

And with a cracked piston you do not see any kind of smoke on the exhaust?
I think the better way right now is to wait and change the parts ordered.

Possibly, but the excessive crankcase pressure is a "tell-tale" of a possible cracked piston or badly worn rings....there's nowhere else it can get in really, and since you have no major exhaust smoke but plenty of crankcase pressure and smoke combined with low compression only on one cylinder....I still believe you have a poorly piston.

Lord Knobrot

[rebuilder86]

ive just realised this reply was to me......
"No movement in / out only a little bit up/down but the rotor don't touch the side wall."
If thats talkign about the turbo, then its shot, it shouldnt move at all. You have the same problem as me and its the turbo,

[Drake1793]

ive just realised this reply was to me......
"No movement in / out only a little bit up/down but the rotor don't touch the side wall."
If thats talkign about the turbo, then its shot, it shouldnt move at all. You have the same problem as me and its the turbo,

Let's see one piece at time.
I think a little movement is normal, when the engine is running should be filled by engine oil.