oil in TD5 Airbox Filter

[onebob]

Just got around to cleaning up my D2 after spending the Melbourne Cup long weekend up in the High Country. We base camped in the Wonnangatta Valley and did a lot of tracks in the surrounding hills - a magnificent time was had with lots of hard driving. After swabbing down the bodywork i next got in and washed the dust out the engine bay and afterwards got on with checking the fluids and then the air box filter. At this point i should say that i have a snorkel and a new airbox filter was installed before the trip however when checking the filter we found it not only contaminated with dust but also oil - the bizarre aspect of this is that the oily dust was on the bottom fluted side of the filter - the snorkel side. The top side of the filter (MAF side) was looking as new. I could understand oil contamination on the MAF side because the crankcase breather pipe enters the air intake after the MAF - but on the snorkel side, well that's bizarre!

Can anybody throw light on this.......

onebob

[stallie]

Assuming you didn't install it then did they put a strip of grease around the lip to stop dust coming in, and the grease has separated into oil?

[Disco W.A]

I can't explain it but mine does the same thing.

[onebob]

Yup! - i installed the filter.

I have a theory that may be way off beam but here goes.....

When you turn off your TD5 after some hours of hard work doing what it's designed to do - what do you have? .... you have a hot engine with no cooling and no air intake to pull the crankcase fumes into the engine for combustion. The fume will continue to be present whilst the engine and oil is still very hot and the fumes will rise to the highest part of the engine and congregate in the air intake hose and be contained by the filter box at one end and the turbo at the other. As the engine cools the fume cools, gets heavier, and settles in the lowest portion of the air intake ie the airbox and then condenses in the filter.

It makes sense to me ;) although I'm happy to be wrong :angel:

onebob

[TD50WA]

It's contaminants from the air, from being in traffic or following other cars, trucks etc. They burn oils from the blowby or diesel etc, this becomes a fume out of the exhaust and floats in the air. Along you come and this air gets drawn into your intake.
The disco air filter is small by comparison to other 4wds and as a consequence it has a small cross section and they high flow of air is more concentrated through the filter.
The filter condenses the fumes and hence the oily type of stain on the outside of the filter. This happens quickly because of the small size.
Leave it long enough and it becomes a black tarry scum.

Remember you're breathing this rubbish in too!

Cheers
Kev

[onebob]

yup! i'll go with that..... trust me to not see the obvious, although my missus wouldn't be surprised :D

onebob

[OffTrack]

The oil laden air must only occur at snorkel level if that is the case as I'm yet to see any evidence of intake side oil residue in the air box on my non-snorkel equipped D2. :p

It's probably something to do with pressure variations in the intake caused by the snorkel. I'm assuming you all use Safari or similar design snorkels. The forward facing head on the Safari is going to cause far greater pressure variation than stock, and you might even find the large black air heater attached to the front guard is causing a chimney effect when parked with the motor off.

I'd be interested to know if this phenomena occurs with the Mantec snorkel as the rear facing intake and plenum hidden inside the guard would eliminate these two factors. If the Mantec shows the same oiling issue then the cause of the problem will be something else.

cheers
Paul

[onebob]

Like Offtrack I never saw oil on the intake side of the filter BEFORE i installed the Snorkel.

Its been installed only 6 months - and mine is a MANTEC.

onebob

[OffTrack]

So it's got to be the fact that there is a snorkel installed, rather than the type of snorkel.

The obvious difference between stock and snorkel is the volume of air contained in the intake tract. Doing a bit of a googling, it seems that suddenly stopping flow of a fluid (like air) causes a pressure build up, followed by a reversal of flow. It seems likely that the additional volume of air in the snorkel will cause a greater pressure build up, and a larger reversal of air flow through the filter. It's not likely to be a huge amount of flow but possibly enough to cause the oil to wick through the filter?

[TD50WA]

In my defence for my above post, it's something I read on a k&n website some time ago, I looked for it last night but can't find it.
I have a snorkel but I haven't noticed it happening yet, well certainly not to any degree of notice anyway.
In my surf it is quite noticeable and it doesn't have a snorkel. The engine breather on the surf is down by the turbo which is about 4' from the air filter and the intake is absolutely dry.
As the surf filter is a large round filter, I tend to just rotate it and blow it out, but it does have the oily tarry scum showing on it in places over time.
The disco filter gets changed more often being so small, so maybe doesn't show as much.
Logic also dictates, no oil on inside, only on outside, no oil input from car, so must come in from outside? Until someone shows me how my engine is oiling up my own filter, without leaving any oil drips in the pipe or inside the air box, I'm going with the info from k&n.
Cheers
Kev:D

[BIG O]

Just checked our two D2's.:)
One with snorkel - oil residue.
One without snorkel -no oil residue.

[bsperka]

Yup! - i installed the filter.

I have a theory that may be way off beam but here goes.....

When you turn off your TD5 after some hours of hard work doing what it's designed to do - what do you have? .... you have a hot engine with no cooling and no air intake to pull the crankcase fumes into the engine for combustion. The fume will continue to be present whilst the engine and oil is still very hot and the fumes will rise to the highest part of the engine and congregate in the air intake hose and be contained by the filter box at one end and the turbo at the other. As the engine cools the fume cools, gets heavier, and settles in the lowest portion of the air intake ie the airbox and then condenses in the filter.

It makes sense to me ;) although I'm happy to be wrong :angel:

onebob

Agree with you on this hypothesis. The fumes will also be venting into the air intake whilst the engine is hot, making its way down to the air box.

[Hay Ewe]

So if one was to only drive in the bush / rural areas, there would be less oil becuase the air is cleaner - no traffic fumes etc....

Hay Ewe

[OffTrack]

If you have a snorkel it's not a problem in areas with a large population of oil particle collecting faeries. From the OP's post they must be scarce in the Vic High Country and on the Mornington Peninsula.

Obviously this is only an issue with a snorkel because the oil mist apparently only occurs at precisely snorkel height. Luckily it's only a narrow band the faeries have to operate in.

Anyone else like to offer up a faerie tale to explain how this occurs? ;)

[worane]

I don't say this very often, and I am very careful who I say it to, But I'm with the fairies on this one!

[TD50WA]

as I said guys, if there is another theory, bring it on, my car that has oil in the filter does NOT have a snorkel and is used mainly for suburban running whereas my disco with a snorkel get used mainly country/low traffic does NOT have oil contam.
This is NOT my theory, but one I found on a reputable manufacturers site (K&N Filters) several years ago.
I have done NO testing to validate this theory, but in the abscence of ANY oil residue on the inside of the air intake after the filter, and an oily scummy layer on the outside of the filter....it would have to be a good theory to prove that it was coming back from the motor without touching anything else....but by all means lets hear a valid theory that explains it...:D

cheers all
kev

[alien]

Yup! - i installed the filter.

I have a theory that may be way off beam but here goes.....

When you turn off your TD5 after some hours of hard work doing what it's designed to do - what do you have? .... you have a hot engine with no cooling and no air intake to pull the crankcase fumes into the engine for combustion. The fume will continue to be present whilst the engine and oil is still very hot and the fumes will rise to the highest part of the engine and congregate in the air intake hose and be contained by the filter box at one end and the turbo at the other. As the engine cools the fume cools, gets heavier, and settles in the lowest portion of the air intake ie the airbox and then condenses in the filter.

It makes sense to me ;) although I'm happy to be wrong :angel:

onebob
IIRC it only oils the filter under the outlet so the above theory could be close.
It may also acount for the AFM contamination we seam to get;)

My addition is as the oil mist condenses it sits on the filter and soaks into the paper from the motor side.
It's visable to us as the bit we look at is the lower most part of the filter when fitted in the air box.

And I'm also happy to be wrong, I was once :twisted::angel:

[nismine01]

Jeez that's enough to get my head kicked in.

My TD5 Disco has no snorkel yet but it does have quite a pool of oil in the bottom of the air box.

Point by point.

If the oil is in the air it would be filtered by the filter (that's what it's for), if the oil was residue after switching off as described it would seep through the filter.

My filter is as dry as a bone, the MAF sensor and tube is oily so the engine side would seem to be the culprit but how does the oil get through the filter without effecting it?

It's got me Alice.

I intend to put an oil catch can in the vent hose and see what difference that makes, maybe someone who has already done that can buy in with the results.

Mike

:wasntme:

[Tombie]

Missing the most simple thing..

Snorkel = exposed intake, particles in air travel directly to the filter

Sans-Snorkel = shielded intake, particles in air have to find their way around the guard, into the void between guard and wheel liner and then into the filter.

Bullbar exposes the in guard unit more (cut bottom etc)