Thread: oil in TD5 Airbox Filter

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?

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

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

onebob

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

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

onebob

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.

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

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

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?