Thread: oil in TD5 Airbox Filter

Originally Posted by 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

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.

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

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?

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!

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...

cheers all
kev

Originally Posted by 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

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

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