Iglugluk

Hi,
I've got a mysterious oil leak happening..
When I run the car and then stop I have oil burning off of the underside of the cat and can smell burning oil in the cabin.. NOT on the topside of the exhaust only the underside/roadside.. its seems particularly when driving at speed not when pottering around.
I've had the car up on ramps and cannot see where it's coming from.. the engine looks dry as does the gearbox. I've had a garage look at it on ramps and they've said the same.
The car isn't showing any issue with engine oil level or gearbox oil level and doesn't leave any drops on the drive when not in use.
The fact it's only on the underside of the exhaust has me stumped right now.
Any advice appreciated.
Cheers A

RockyRoad

Have you recently had the oil changed? The filter is perfectly placed to dump a load of oil on the exhaust and it can sit inside the heat shields.

Iglugluk

I did wonder about that and yes the oil was changed. How long would you think it may occur for if that is the issue?

RockyRoad

Depends how much oil is in there. I usually find a good spray with brake clean (with the exhaust cold!) helps to flush the oil out. That assumes you don’t actually have a leak somewhere.

Double check the oil cooler modine (above the filter), both rocker cover gaskets, the sump and if there’s a leak from the rear main seal coming down near the flywheel. Also worth checking your power steering system for leaks.

Iglugluk

Not much oil but it smells and smokes after stopping
cheers.. pretty sure rocker covers are ok they're dry with no streaking.sump is dry too had it checked when it was on the ramp at a garage.
Like you said someone has mentioned it could be a main seal leak coming out of the bell housing drain hole.

RockyRoad

Unless you're looking at the rocker covers underneath you're likely to miss a leak. Oil can "stick" to the head and travel along and down the exhaust. Unless there was a lot of oil spilled during the change I wouldn't expect it to still be burning off after more than a few decent drives. Does sound like you've likely got a leak somewhere.

Iglugluk

Unfortunately I suspect you are right.
Would oil leaking from the rocker covers streak along the bottom of the exhaust only when driving at speed and not at all under 50mph?
Btw I have noticed a drip of oil sitting regularly on the bottom of the oil filter 🤔
BIG thanks for the advice
Don't suppose you know anything about starting issues.. I've got a thread on the lighting and electrical section? 🙂

RockyRoad

That's probably either the filter itself leaking (try tightening it by hand) or the oil cooler modine. There's a rubber seal on the top of the modine that can leak. It could be as simple as some debris on the mating surface when the filter was changed, the old seal was stuck and wasn't removed so you've got a double seal or the seal on the filter could have been damaged.

Iglugluk

I changed the filter and oil again last week and problem has persisted so it's unlikely same thing twice.. the modine hasn't been checked so I'll check that 👍