Audi A4 oil pressure alarm

Heroditas

Got the Audi serviced on Thursday and was travelling to Cork on Friday when the oil pressure alarm came on. I was coming out of a petrol station on a busy stretch so floored it to get up to speed quickly and not interrupt the traffic flow. A minute or two later the alarm came on and went off after 5 seconds. It then proceeded to come on and off every so often the rest of the way to Cork resulting me in nearly passing out with nerves afraid it would pack up and die.
Anyway, no alarms the next day and today I had to drive back up to Dublin. Made it all the way up without any excessive revving of the engine (kept it at the 3000rpm range) and again there's no alarm.
I'm bringing it back to the garage on Tuesday but anyone any ideas what could be the issue here? Phoned the garage on Saturday and they said it could be a build-up of muck in the engine.
Does it sound like the oil needs to be purged, bearing in mind it only just had an oil change? It was filled with long life oil.
I'd typically do a mix of driving - either long range motorway drives or short hops in the city.

Mr Benevolent

Could it be something as simple as the oil sloshing backwards during acceleration and uncovering the sensor? Only a thought, but the fact that it didn't come on with gentle acceleration makes some sense.

Neilw

Did you check the oil level after the service?

Heroditas

Yup. Completely topped up and where it should be.

crosstownk

This alarm should have lit up the oil can lamp on the dash.

If so was the lamp red (low oil pressure) or yellow (low oil level). It's not unusual for the sensors themselves to give trouble. I've seen it regularly on VAG models.

Heroditas

A red oil can lamp lit up in the middle of the dash - in the main panel that indicates the distance to next fill, radio station selected etc.

wazzoraybelle

I had the same issue with my diesel A4. Bought it to a few mechanics and none could pinpoint the problem. Was going to have sensor replaced before a clumsy truck driver saved me the bother and wrote off my car!

DvB

Sounds like a problem i had with my A4 before i got rid, ended up it was the oil level sensor that needed replacing, kept on appearing despite the oil levels being fine, i'd had numerous issues with sensors & driving the thing had my nerves in shreds, I was good friends with the service dept girl that dealt with me by the time i sold it on it had been in with them so much. Funnily enough i always seemed to have the problem just after a service.

Heroditas

DvB wrote: »

Funnily enough i always seemed to have the problem just after a service.

Interesting!
The problem hasn't happened in the last few days since last Friday.
Engine sounds ok so I haven't dropped the car back in yet.
I'll drop it in anyway just to be on the safe side.

Biro

1.8T?

Heroditas

Biro wrote: »

1.8T?

Yes.

Heroditas

Well, got it fixed in the end.
Massive amount of carbon build-up in the gauze in the sump. About half of the gauze was blocked with "burnt oil".
Anyhoo, all working ok again. Engine hasn't sounded this smooth and quiet for quite a while.

Neilw

Heroditas wrote: »

Well, got it fixed in the end.
Massive amount of carbon build-up in the gauze in the sump. About half of the gauze was blocked with "burnt oil".
Anyhoo, all working ok again. Engine hasn't sounded this smooth and quiet for quite a while.

That's due to not replacing your oil at regular intervals or using poor quality oil. This is especially important for longitudinal arranged 1.8t engines such as passat/a4. The sump is very small in these and there is less oil which sludges up fairly easily.

To reduce the chance of this happening again I would (and I do) change the oil every 5-6k miles with good quality fully synthetic.

Heroditas

Neilw wrote: »

That's due to not replacing your oil at regular intervals or using poor quality oil. This is especially important for longitudinal arranged 1.8t engines such as passat/a4. The sump is very small in these and there is less oil which sludges up fairly easily.

To reduce the chance of this happening again I would (and I do) change the oil every 5-6k miles with good quality fully synthetic.

Yeah, only got the car last September and this was its first servicing since then so God only knows what was used the last time or even the time before that.