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I accidentally left the oil filler cap off for a few hours, just before doing a few minutes of beach driving over some bumpy conditions. Lost oil but I topped it back up. My fuel economy dropped (I watch a spot just less than half-full to estimate my economy) so I suspected a fouled air-cleaner.

I'd just changed it 3-4 weeks ago when I noticed the same drop in power and economy.
Only last time it was just gummed up with red dust from Shark Bay.
This time there was about 100-200mL of oil sprayed around my air box, some of it puddling near the front.
Very weird.

I wiped up the oil with many paper towels...
I've yet to buy another filter (I work too much + WA's famous short shopping hours )
I checked it today and saw a tiny puddle after only 40 km of driving.

Head gaskets?? I think I read something about oil in the air filter somewhere

Hope you get it sorted out mate.

It's just blow by. Kinda normal on a vehicle this age. Has something to do with pcv lines etc.

It however shouldn't effect fuel economy or power.

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It's from the return line from one of your Rockers. It's a breather.
Mine was mixed with coolant. (Head Gasket).
Ultimatly it would be nice to stop it.
You may be taking the heads off etc, though.
But unless, it is mixed with coolant, wrecks your airfilter, or goes into your carby.
I think your pretty safe.

Cheers Cam

As a few have said about the blow by.

Blow by is the term used when your rings on the pistons are worn, you're losing some of the power of the explosion as it pushes past the rings rather than pushing the piston down the cylinder.

This blow by can pressurise the crank case which then needs an outlet. New engines these days have this plumbed into the air filter to re-burn the stuff for pollution control. So what you're seeing is the very fine oil particles being push out of the crank case and into your air filter creating a pool of oil.

If you over fill your sump this will be more evident as you may have moving engine parts in contact with the oil - you'll notice a change in your performance as the engine needs to work harder to move the oil out of the way of the moving parts internally. By splashing the oil around violently it will mist up in the air of the crank case, this with blowby will end up in your air filter.

If it's really bad you'll see blue smoke out the back of the car - this usually indicates that the oil rings are shot though, usually from too much over-revving or running your engine too low on oil. Either way it's a rebuild to sort it out.

For your situation though there's a couple of tricks that might help out: The one I know of is to make up an oil catch can that sits above the cam cover plates where the crank ventilation pipe mounts, you just need to make a box with a tube at each end, shove some stainless steel in it, seal it up and place in the line. The idea here is to make the oil filled air move through the stainless steel (non soapy one), the oil sticks to the stainless steel, drips to the bottom of the container, pools a little more then drops cleanly back into your engine so it can do the whole thing all over again later.

Cheers

Bennie

El_Freddo wrote:this usually indicates that the oil rings are shot though, usually from too much over-revving or running your engine too low on oil. Either way it's a rebuild to sort it out.

Just one reason why I nurse my baby, not rev the crap out of it

The one I know of is to make up an oil catch can that sits above the cam cover plates where the crank ventilation pipe mounts, you just need to make a box with a tube at each end, shove some stainless steel (ED: wool) in it, seal it up and place in the line. The idea here is to make the oil filled air move through the stainless steel (non soapy one), the oil sticks to the stainless steel, drips to the bottom of the container, pools a little more then drops cleanly back into your engine so it can do the whole thing all over again later.

Very clever, I hope I never have to do it but handy to know if I do

What can you suggest to use as the can?

Im hard on mine but I don't over rev it. Although the oil has run very low quite a few times.

But with over 300,000km on the engine in your L-Series maybe its time to start looking at other options if it gets alot worse.

Overfilling the oil, using the wrong type of oil, oil getting to hot, oil rings wearing out, partially blocked air filters, any many more things can cause this. You'll need to just keep an eye on it for now and if it gets really bad then start changing some stuff.

It seems to be fine now.

After cleaning out the air box with paper tools I started it up without the air filter.
Night and day difference. My "new" air filter was already stuffed...
Probably fouled by the oil that got in there.

Got a new filter.
I also changed my oil and added 1L of "oil treatment".
Don't remember which kind, the bottle's in the bottom of the bin.
It's from an Australian company, bought in Rockingham's Auto One.
Half the price of Lucas Oil Treatment.
It seemed to be A LOT thicker than my 20W50
and now it seems my "death rattle" is gone.

Decided to try Valvoline's fuel and carby cleaner, fuel tank additive.
Seems to have helped. It sounded like my motor was a bit livelier I added it.

Will try to behave with the throttle, see how my fuel economy looks after a few hundred km's.

Good to hear Matt. Also a good idea to look at the washable/reusable air filters, like Uni-Filter or K&N.. not sure if they still make them for your model but worth a look next time.

Engine blow by can be caught in an oil catch can before it gets to the air cleaner, but I would start saving money for the transplant (EJ 25) instead and back off on the loud pedal

TOONGA

i have have had oil in the intake area before. Lots of it. Was caused by all the PCV hoses being blocked with carbon (completely blocked) , not allowing the engine to breath properly.

Just check all your hoses PCV realated hoses are clear of carbon.

An oil catch can is also a good idea, but not entirely necessary on a standard setup with everything working properly.

I have one on my L series, made from an air compressor filter, works a treat.

The crankcase vapours were an issue for me as I've got twin carbs and the breathers were venting to the engine bay not back into the intake. Sometimes the fumes inside the car were so bad I had to stick my head out the window. I have heard of similar issues when people do webber conversions.

Since the catch can went on, all is good. No vapours in the cab and oil is catching in the air compressor filter. I'll see if I can find a photo of the setup

Cheers
Sam

A link to a catch can discussion on the RS forum.
http://www.rslibertyclub.org/forums/sho ... ight=catch

Not a suby but I used a air compressor filter like this:
http://www.srtforums.com/forums/f75/how ... all-97923/

from the breathers, through the catch can and into the intake.

subius wrote:i have have had oil in the intake area before. Lots of it. Was caused by all the PCV hoses being blocked with carbon (completely blocked) , not allowing the engine to breath properly.

Just check all your hoses PCV realated hoses are clear of carbon.

An oil catch can is also a good idea, but not entirely necessary on a standard setup with everything working properly.

I have one on my L series, made from an air compressor filter, works a treat.

The crankcase vapours were an issue for me as I've got twin carbs and the breathers were venting to the engine bay not back into the intake. Sometimes the fumes inside the car were so bad I had to stick my head out the window. I have heard of similar issues when people do webber conversions.

Since the catch can went on, all is good. No vapours in the cab and oil is catching in the air compressor filter. I'll see if I can find a photo of the setup

Cheers
Sam

Can't see how 'completely blocked' breather lines could allow oil up to the air filter

You said you had left the oil filler cap off? There's your culprit.
With the cap off, the PCV system sucks air through the crankcase like mad, and the extra flow is what pulled the oil up the PCV hose and into your airbox.
Happened to me when I lost my oil cap for a week.

RSR 555 wrote:Can't see how 'completely blocked' breather lines could allow oil up to the air filter

Nah, not the crankcase breathers, they were clear and oil was being pushed up into the aircleaner. As previously mentioned, blow by probably had something to do with it. But that alone wouldn't have caused the amount of oil I was getting in the air cleaner. The hoses connected to the back of the PCV valvle were full of carbon. And I would get huge plumes of blue smoke every now and then out the exhaust.

Anywhat that's all fixed now, i'll stop the hijack

subius wrote:Nah, not the crankcase breathers, they were clear and oil was being pushed up into the aircleaner. As previously mentioned, blow by probably had something to do with it. But that alone wouldn't have caused the amount of oil I was getting in the air cleaner. The hoses connected to the back of the PCV valvle were full of carbon. And I would get huge plumes of blue smoke every now and then out the exhaust.

Anywhat that's all fixed now, i'll stop the hijack

subius wrote:i have have had oil in the intake area before. Lots of it. Was caused by all the PCV hoses being blocked with carbon (completely blocked) , not allowing the engine to breath properly.

Just check all your hoses PCV realated hoses are clear of carbon.

An oil catch can is also a good idea, but not entirely necessary on a standard setup with everything working properly.

Oh sorry Sam, I thought you said all of them and I thought PCV meant Positive Crank Valve.. my mistake but I was having a laugh. Nothing against you.

Battlewagon wrote:You said you had left the oil filler cap off? There's your culprit.
With the cap off, the PCV system sucks air through the crankcase like mad, and the extra flow is what pulled the oil up the PCV hose and into your airbox.
Happened to me when I lost my oil cap for a week.

Yep.. this would have started it all off.