Yellow gunk in airbox

daveharnett · 14-07-2008 11:03PM #1

This relates to a 1.6 mk3 golf.

When I was changing the air filter yesterday, I noticed some nasty looking yellow gunk at the end of the hose that connects the crankcase to the airbox. Also, a little rubber ring which was over the top of the hose has come off and was lying on the floor of the box.

There was also a little oil around the floor of the box, and on the sides of the throttle body, but I understand that this is normal by-product of gas getting past the pistons and into the crankcase.

What ahout the yellow sh**e though?

Martron · 14-07-2008 11:29PM

when water air and oil mix they make an orange gunge. sometimes if you find that under the oil cap. afaik.

daveharnett · 15-07-2008 09:03AM

Martron wrote: »

when water air and oil mix they make an orange gunge. sometimes if you find that under the oil cap. afaik.

well, that's a relief!

ART6 · 15-07-2008 06:02PM

Martron wrote: »

when water air and oil mix they make an orange gunge. sometimes if you find that under the oil cap. afaik.

Some engines, including earlier Ford Fiestas, did that all the time. Generally it's an indicator of a leaking head gasket, but certainly not in every case.

milltown · 15-07-2008 06:11PM

Relax, the gunk in your airbox is most likely to be from the PCV valve. If there was a lot of it on the inside of your oil cap I'd worry but not where you say you found it. For emmissions regulations the crankcase air (with it's natural oil and hydrocarbon content) cannot be vented to atmosphere so it's routed back to the airbox where it can be burnt in the engine. When the warm oily air from the crankcase mixes with the cold damp air coming through the airbox, the oil and water emulsify leaving you with creamy "mayonaise".

Martron · 15-07-2008 07:17PM

mayonaisse....... good description

Esel · 15-07-2008 10:21PM

Martron wrote: »

mayonaisse....... good description

Bad when you see it on the underneath of the oil filler cap though!

Yellow gunk in airbox

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