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[iansoutham]

Have looked through the search facility and can not find anything particularly relevant so, question out to the masses....

I have always had oil residue coming from the intake elbow by the throttle body since I owned the car in 2013.
Breathers have been cleaned previously, small air breather hole in the manifold as well.
Car has the modified breather (flame trap box) and breather metal pipe to block removed and cleaned
Idle is good
Cam cover had been removed previously and completely cleaned out through all sections about a year ago, (they were blocked as you would expect), gasket was not leaking when removed, nor now
ISCV is not blocked
Emissions are good 0.03% CO, 14ppm HC.

Oil level only goes down due to leaking front crank seal.

Logically, this would have positive crank pressure but I can see no obvious reason unless it is so obvious I am missing it. I was under the car the other day in work and noticed that the whole bottom of the inlet manifold is soaked in oil residue so, as I like clean engine bays, this is unacceptable and needs fixing.

My old X20XEV Cavalier used to do it as well but that was sold before I could be bothered to look at it.

I have a few days off before Christmas this year (1st time in 17 years) so want to get a few jobs done on all the car.

Front crank seal being done, levels all checked and car to be gone through completely if possible (hence trip to ramp in work last weekend). Will be rechecking all of the above anyway as a matter of course) but any other thoughts or ideas are welcomed.

[Doctor Gollum]

Basic physics and a common side effect of the Omega design...

Hot oil fumes get sucked up through the breathers... Some goes straight into the plenum via the top hat fitting on the breather bridge (the two small pipes one is the breather box vent, the other is actually from the purgevalve/charcoal box). The two larger pipes, (from the large outlet on the breather box) vent to the outside of the throttle body... When the throttle is opened, the airflow creates a hefty vacuum on the breather system.

This draws up the hot oil fumes from the crank case. As this cools it condenses back to liquid oil and will effectively drain in to the mouth of the throttle body and on to the intake pipes. After a while this adds up to a reasonable amount of oil at the lowest point.

Incidentally if there's any condensation within the engine, this becomes steam along with the oil fumes, and as the engine cools, this also condenses, usually within the breather bridge. This is what clogs it all up and why regular breather cleaning and decent oil are important. The small pipes clog first, which increases the apparent amount of oil at the intake.

Better oil, more frequent cleaning and less short, cold journeys are the easiest ways to counter it, but you can never stop it happening.

[deviator]

Or you could block off the inlet on the plenum and buy an oil catch can, which will allow the crankcase to breathe, without it being sucked into the inlet. Just be careful with catch can you buy, some are not designed very well.

[Doctor Gollum]

You can only do this with the oil breathers... Doing it with the charcoal cannister pipe is potentially asking for trouble as you're collecting fuel vapour 

[deviator]

You can only do this with the oil breathers... Doing it with the charcoal cannister pipe is potentially asking for trouble as you're collecting fuel vapour 

Well yes, I thought that would be obvious with it being called an oil catch can and the fact he isn't getting oil in his inlet from the tank vent.

[Doctor Gollum]

Well, there's that 

[iansoutham]

Okay, if it is normal then it is not so much of a problem.

Was thinking about putting a drain in the bottom of the manifold using a sump plug to drain excess oil every so often? Problem is that the car does about 4-5 miles each way to work every day in SE London and only gets runs every so often. Oil is good quality 10w40 semi-synth and changed every 5k

[Doctor Gollum]

You should probably buy a Leaf if that's how you use it...

But if the oil build up bothers you, just pop off one of the elbows every so often and suck it out with a hand pump

May also be worth halving the oil changes.

[iansoutham]

You should probably buy a Leaf if that's how you use it...

But if the oil build up bothers you, just pop off one of the elbows every so often and suck it out with a hand pump

May also be worth halving the oil changes.

13 minutes to work, 20 minutes or so to get home but is ideal for the journey in the form of comfort and “get out of my car” factor.

I could use one of my company cars if I wanted, I still prefer mine as it is mine, nobody else’s and I don’t have to answer to anyone if something happens to it.

[Doctor Gollum]

You're missing the point, five miles in 13-20 minutes is no good for it, and will only serve to exaggerate the issues that you are finding. A works vehicle would suffer in exactly the same way, so wouldn't solve the issue. You would be a textbook candidate for going electric.

But, if the price of comfort is significantly more intensive maintenance then that's up to you

[Nick W]

You're missing the point, five miles in 13-20 minutes is no good for it, and will only serve to exaggerate the issues that you are finding. A works vehicle would suffer in exactly the same way, so wouldn't solve the issue. You would be a textbook candidate for going electric.

It wouldn't solve the issue, but would make it SEP. Which is always good

[Doctor Gollum]

True dat

[iansoutham]

You're missing the point, five miles in 13-20 minutes is no good for it, and will only serve to exaggerate the issues that you are finding. A works vehicle would suffer in exactly the same way, so wouldn't solve the issue. You would be a textbook candidate for going electric.

But, if the price of comfort is significantly more intensive maintenance then that's up to you

The point of using my own car is it costs less in fuel than the BiK and other costs of using a company car, plus I have a bad back and left knee with hardly any cartilage left so driving an M4, new X7 or 7-series and manoeuvring it through traffic is annoying and borderline painful where as the Omega is comfortable and, believe it or not, quicker. Also, my no claims are on that car.

The car is not only used for short journeys, it does journeys cross country as well (just not this year).

If the cost of comfort is using a ramp in work to change the oil more frequently and clean the throttle body every 6-12 months, I can live with that.

Additionally, I refuse to pay monthly instalments on a car that are more than I paid for the current car, plus other costs

[Doctor Gollum]

I never said that the alternative had to be a company car...

I agree re monthly payments etc, and also the importance of being comfortable