450 engine - oil consumption

[d harry]

Hello again,

my 2001 450 has almost 70.000 kms (about 44000 miles) on the clock, engine runs fine, but I noticed oil consumption, quite high on my standards: almost 1 L every 1000kms (625 miles).
Last month I changed the spark plugs, they were in good shape, colour and deposits were about the same on each cylinder; I can see no white or blue smoke from the exhaust.

So the question is: where does all this (100% expensive synth) oil go?

The only strange thing I noticed is that turbo on the intake side is wet with oil, not dripping, just a bit wet; I also noticed that a nut might be missing on the turbo exhaust manifold, but I'm not sure, got to check it better.

thank you,

DH

[RacingSnake]

Re: 450 engine - oil consumption

the oil will be being burnt.
either past the piston rings, the valve stem seals, or crankcase breather (or combination of all).
The wet oil on the intake side of the turbo is coming from the breather, which is normal, it will always pass some oil vapour, but I suspect that the additional crank case pressure is forcing more than usual through the breather pipes.

In essence, you're seeing the junior stages of Engine rebuild time!!!

I wrote a small article here on oil consumption

http://www.fq101.co.uk/articles/25-high-oil-consumption.html

[d harry]

Re: 450 engine - oil consumption

the oil will be being burnt.
either past the piston rings, the valve stem seals, or crankcase breather (or combination of all).
The wet oil on the intake side of the turbo is coming from the breather, which is normal, it will always pass some oil vapour, but I suspect that the additional crank case pressure is forcing more than usual through the breather pipes.

thank you! As you suggest, I'm going to check the crankcase breather valve first: if I take out the oil dipstick, then I start the engine, if this valve is locked I should notice some fumes being forced out from the dipstick tube, right?

By "wet" turbo I meant wet on the outside, intake side... is this also normal?


thank you again,

DH

[tolsen]

Re: 450 engine - oil consumption

thank you! As you suggest, I'm going to check the crankcase breather valve first: if I take out the oil dipstick, then I start the engine, if this valve is locked I should notice some fumes being forced out from the dipstick tube, right?DH

Lower end of dip stick tube is submerged in oil so you won't see any fumes steaming out.

[Thrumbleux]

Re: 450 engine - oil consumption

Disconnect the upper breather at the throttle body and blow down it. The valve should close immediately. Any delay (or leakge past it) means replacement required.

[madDan]

Re: 450 engine - oil consumption

then wipe all the oil out of your gob, do not swallow

[Thrumbleux]

Re: 450 engine - oil consumption

then wipe all the oil out of your gob, do not swallow

Blow - not suck.

[d harry]

Re: 450 engine - oil consumption

Disconnect the upper breather at the throttle body and blow down it. The valve should close immediately. Any delay (or leakge past it) means replacement required.

interesting... I'll give it a try, thanks


DH

[ethanol-smart]

Re: 450 engine - oil consumption

Lower end of dip stick tube is submerged in oil so you won't see any fumes steaming out.

Which is an extremely stupid design...If large overpressure in the crankcase of any reason, the oil is pushing it self out through the stick pipe...What was going on in the heads of the engine designers???

As alternative to judge the crankcase pressure, one can take off the oil filling cap instead.
On a healthy engine, the cap should be able to sit, lightly sucked against the valve cover during all conditions.
If even on low rpms, the cap jumps off, there is over pressure in the crankcase, which is a sign of either bad ventilation and/or leaking piston rings.
This is a quick test that one always should do when looking on cars to buy. (All cars)

[madDan]

Re: 450 engine - oil consumption

Blow - not suck.

You take the breather out the end will be oily whatever your preference, and just because the cars are smart most owners aren't

[d harry]

Re: 450 engine - oil consumption

What was going on in the heads of the designers???

about the same thing that was already in their heads when they made the transparent sunshields :-)

Note: in the smart car you can't try the crankcase pressure with the oil cap trick, because distribution chain is right under it and will spray oil everywhere.

DH

[d harry]

Re: 450 engine - oil consumption

You take the breather out the end will be oily whatever your preference, and just because the cars are smart most owners aren't

I might clean it with some paper... how would you check the breather valve then?

thanks,

DH

[madDan]

Re: 450 engine - oil consumption

No point just checking it one way, you need to check it bothways as they also sieze up closed or the pipe gums up, make sure its clean, blow from both ends, that would require pulling the other end of the pipe off.


It should open and flow freely towards the throttle/manifold inlet and completely close when blown the other way.

[d harry]

Re: 450 engine - oil consumption

No point just checking it one way, you need to check it bothways as they also sieze up closed or the pipe gums up, make sure its clean, blow from both ends, that would require pulling the other end of the pipe off.

It should open and flow freely towards the throttle/manifold inlet and completely close when blown the other way.

Just checked... the valve was full of dry carbon, surprisingly no oil at all. It was just leaking a bit, I sprayed it with some WD40, now it seems tight... but I'm afraid it's broken elsewhere, from intake side it enters the rubber pipe about 3cms, from crankcase side just 1/2 cm. The rest of the pipe seems still ok... I was thinking of fitting just a new valve, I have in front of my house a plumbing shop, maybe they can help me somehow :-)

What do you think it's going to happen if I simply take the valve away and put a cap at both ends of the pipe?

thank you all,

DH

[Thrumbleux]

Re: 450 engine - oil consumption

What do you think it's going to happen if I simply take the valve away and put a cap at both ends of the pipe?

thank you all,

DH

Probably you will lose the effect of the vapours in the crankcase circulating and being drawn out. Vapours will contain some fuel (potentially explosive) and will dilute the oil. Not good.