Hi guys,

I’ve got an oil pressure problem on my Audi A3 2001 8L1 engine AVU 1.6 petrol. I’m stuck with the diagnostic capabilities of the garages.... Any idea?

The problem: When the engine is running hot and the rev drops suddenly to idle, the oil pressure alarm goes off while idling. Typically at stopping at the red lamp at the end of the slip road when exiting the motorway. Alarm disappears by increasing rev and usually does not repeat when the engine got a bit cooler.

What is known:

1. Oil pressure sensor was replaced by local garage, so it must be ok. They said if problem persists then oil pump is wearing off and time to scrap the car.
2. The problem disappeared for a while (for a 1000 miles) right after oil change.
3. The temp. gauge is unreliable on the dashboard; that means that sometimes it shows 140C even when cold and the temperature alarm goes off. (Otherwise cooling system is fine.) This exists for years, much longer than the oil problem first happened.
4. The oil sump was replaced 2 years ago (had a cracked sump from previous owner) by local garage.
5. Audi dealer spent 3 hours on diagnosing the problem, measured oil pressure, made test routes. They could reproduce the problem only once on the roadside but the alarm disappeared by the time the technician pulled over and checked the diagnostic pressure meter mounted on the engine. I have also seen the pressure values while the car in the garage, they were normal and reacted well to the accelerator. The dealer concluded that this might be another false alarm of the dashboard and oil pump, relief valve are not apparently faulty.
6. The oil breather pipe is broken completely (No. 19 on top of the oil filter bracket -- it’s a hose going to the air intake on my model) probably for years. AUDI A3/S3/SPORTBACK/QU. [A3] (EUROPE) 2001: ENGINE: 11550. OIL FILTER BRACKET; OIL FILTER

My actual guess is that there is some light blockage (or sticking) either at the relief valve or at the pickup strainer (maybe too much sealant at sump replacement or due to the opening dirt got into the sump). Does this sound likely?

I want to check the oil pressure relief valve first. (No. 6. in fig) It’s very close to the metal oil dipstick pipe. Any experience with its removal? Is it removable without removing the complete bracket (or the dipstick pipe from the block?) ?

Cheers,
Gabor