B6 S4 - slow oil drip from 'central gutter'

[cliaz]

As the title says, I've had a very slow oil drip in my B6 S4. My mechanic says it's common and likely from a gasket leaking into the 'central gutter', and not identifiable / rectifiable without significant effort. He's done thorough inspections from the bottom up a couple of times and not found any obvious signs of a leak.

Anyone have experience with this, specifically the 'central gutter' part of things? Totally new term to me.

Cheers!

[TheChenga]

Most likely valley pan gasket. I had that leak and it's hard to spot since it's under the intake manifold and will slowly drip down. In my case, I ordered the valley pan gasket kit with oil check valves & valve cover gaskets from ECS.
Oil cooler is also a common leak location.

You could also add some dye to your oil then try and locate the leak with UV light if you want to pinpoint the exact spot.

[cliaz]

re: the UV option - if it's the valley pan gasket which appears to be buried fairly deep (as per the writeup here https://tinyurl.com/44wyj3hk), would the UV additive be see-able?

Good info regardless, I'll see if I can't get that looked at - coming up on a 200k service anyway

[TheChenga]

Should be able to see it from under the car if it's leaking down. It's a good way to eliminate other potential oil leak spots.