Low oil pressure S4 b8.5


Registered User
Just had a service, oil and filter replaced.
Day later I get a "low oil pressure" warning which went away about 5 seconds later. (I heard the beep but didn't actually see the fault). So day after that I drive it for 10 mins and the warning comes on and I see that it's "low oil pressure". I stop the car thinking the worse.

Come back couple of hours later turn it on and nothing, drive home and when I pull up at home it comes on again!!

Instantly I'm thinking the sensor must be playing up, so I think I'll do a manual oil pressure test see the actual pressure. Removed the sensor (proper hard sensor to get to!!!).
On first engine start it read 1.5bar which is within the specs (minimum 1.2 at idle and minimum 1.5 bar 2000 rpm).
Rev to 2k and it pops up a little to just under 2 bar. I'm thinking happy days it's a faulty sensor.

So I turn off the engine and try doing the same test and it's now dropped down to 1.2bar at iddle and 1.7 at 2k.
To make sure, I turn off engine again and give it another shot and this time it's dropped to just bellow 1bar idle and 1.5 at 2k :3sadwalk:

Try one last time and the warning light comes on again :sadlike:

This take the sensor out of the equasion, what else should I be looking at?
I'm really hoping it's not the oil pump as that will probably be a right **** to replace I would imagine


Registered User
It was 5W 40, which is right spec but after taking it back to the garage that did the service and it turns out it's a part / o ring inside the oil filter housing!! (I can't quite see what it could be from the exploded view but guess it sits at the bottom somewhere)

So happy it was something so simple really thought after checking the oil pressure sensor that it was going to be a rocky road to the bottom of my wallet!!
But couple of quid and wait for back order part and will be back in action :yahoo:


Could it be this inner seal "A"? There seems to be a few variants for the 3.0 though.


I'm sure mine is more like this, where I can only see one seal which comes with the filter:


Registered User
@ninjag I'm not too sure I didn't even open the oil filter housing just went straight for the oil pressure sensor (which was a mistake given what a pain it is to get to haha).

But will report back when I find out what it is, I'll try get part number as they had to order it from Audi (which makes me think it wouldn't be just the 3 from the last exploded view as those must be common as muck).


Registered User
For your and your engine's sake, I'd be buying a new oil filter and fitting it complete with all its supplied seals.

In my experience of trying to order in something like a seal that gets supplied with a new filter, the fact that it is "back order" means that no one has ever asked for one, so you will probably have changed cars before that "back order" seal comes into stock.

ECP for instance sell the MANN equivalent oil filter for not much money - and the original VW Group branded oil filter will also have MANN branding printed on it.

In my case it was a petrol fuel filter seal on a 2002 VW Polo, and the reason that I needed to buy one was down to ignorance, the new fuel pressure regulator came with one - 10 years on I'm well past giving up any hope of that "back ordered" seal ever turning up, paid for but never supplied, any way that car was sold on and seems to have died a few years after it was sold on.

Edit:- I've always preferred 5W-30 oil for my B8 S4.


Registered User
The filter comes with new seals included as stated above.
Here is the correct filter for your car - MANN OE Boxed with seals and fitting instructions.


The filter comes with new seals included as stated above.
Here is the correct filter for your car - MANN OE Boxed with seals and fitting instructions.

The height is showing 155mm?


The filter for my B8.5 is only 105mm - you've got me worried now! lol

Here's the one I bought for mine: https://www.eurocarparts.com/p/mann-filter-oil-filter-501440669

I looked up the parts diagrams and got this part number (06E115562B) which returns 105mm height filters?



Registered User
@ninjag you are correct!
In your pictures above, the top two are from a B8 and the lower one is from a B8.5 - very different seals.
I do apologise, I am mistaken, the CAKA & CREC engines have diferent oil filters!
In my defence the mann catalogue lists both engines, however when you go further it splits them.
I have a B8
@cmdv - The correct Mann Filter for B8.5 is HU 7035Y - and it will come with a new seal

Please see attached, and Thanks - learn something every day!


  • Mann.jpg
    132.2 KB · Views: 13
  • CAKA v CREC.jpg
    CAKA v CREC.jpg
    141.2 KB · Views: 11
Last edited:


Registered User
Thanks @ninjag I spoke to my garage again and it's actually the oil bypass/drain valve that sits inside the oil filter housing (lower half)
So it's not the filter and seal that sits between top and bottom. The filter is brand new and the right part number, they are VAG registered so get all the same oils etc from the Audi specs.

Just came to light as new filter was fitted when doing the oil change and it must have disturbed something, apparently it's noted in the audi system as a common fault. (How true that is I'm unsure) But the people at the garage are currently having to store 19 cars waiting for parts on back oder even paying extra giving it a OR (car Off Road or something like that) label.

Sucks because it's such a simple part, I even asked if we can just purchase the whole filter housing thinking that it would maybe be more available but no luck. Just have to go with put my car until it comes in :grumpy:

Better than risking my engine though, rather go without for a little bit that go through that pain. Can imagine how much a new engine would cost and the labour!!!!


I wasn't 100% sure but thanks for clarifying. PenttisHSR, Audi part numbers seem to be a bit of a nightmare with all sorts of revisions. Spent ages trying to verify the correct part numbers for the front suspension and even ended up mistorquing a ball joint as it was the upgraded M14.

Thanks for the extra info cmdv, I'll need to bear that in mind when doing oil changes.