pinstrip89

I have a 2005 Audi A4 1.8T all stock, no aftermarket parts. The low oil pressure warning light keeps showing up on my display while driving, it usually takes about 10-15 minutes for it to come on. I literally just changed my oil today, as well as the oil filter, and the spark plugs. This has happened before, but last time I just had an oil change done to it and it stopped on its own. I assumed this would be the case again, but it is not. I have read a lot of threads and forums in regards to it possibly being the oil pick-up tube, which I am not discrediting, but could it quite honestly just be the oil pressure switch that needs to be replaced or something smaller like that. Im not trying to go broke from bringing it to a dealer for them to tell me I have unicorns and **** jumping around in my engine poking holes and losing oil pressure. Any advice would be greatly appreciated.

lyleswk

Usually indicative of sludge. Do you know the history of the car meaning maintenance routine? Was synthetic used on it?

pinstrip89

Honestly I'm not too sure. It has had three owners, me being the third. I know the second owner from whom I bought it from took care of it, not sure if they used full syn however. I have been using full syn for the past year and a half that I have had it. I replaced the oil pressure switch today, and drove it for about 30 miles with no oil pressure light. Tomorrow will be the defining factor as to wether or not that was the problem seeings how I have a 40 mile drive to work all highway. hopefully it works, I will keep you and the thread posted. Thank you for responding by the way.

pinstrip89

Well oil pressure switch did not work. Backs up against a wall now. I was reading however that someone had ran diesel fuel through his oil pan/ lines at idle rpm for two hours and then put new oil and a new filter back on and he says that resolved the issue of all the built up gunk. Do you think this is safe for the car or even work?

lyleswk

I have read lots of solutions to sludge, but no experience with it. I would check with a dealer and see what they do to solve this issue and see if you can mimic that. Or, maybe some others have a solution.

pinstrip89

I put 1 quart of mystery oil into the system today, well see if that works, so far no joy, but I am going to give it a few days to work. If this doesn't work then I will most likely be pulling the oil pan and cleaning the oil pick up tube.

John535is

I would not be doing the diesel 'trick' on a modern engine. Basically they are just washing the inside of the engine with the thinnest possible liquid that would still technically be considered 'oil'.

Let us know if the Mystery oil additive does anything? Because you just changed your oil recently, it would be interesting to know if this stuff really removes any additional sludge.

The fact you just did an oil & filter change my gut feel is I would be dropping the sump.

You will need a day and the following parts (check the correct part numbers for your engine)
2 Sub-Frame Bolts M12x1.5x110 N90823501 (These are stretch bolts and must be replaced)
4 Sub-Frame Bolts M10x70 N90663002 (These are stretch bolts and must be replaced)
1 Turbo Oil Return Line Gasket 058145757A
The OEM sealant that the dealer uses is white VAG P/N: D176404A2
or ECS Sells elring Dirko P/N: UN1253000 or equivalent.
Pickup Tube O-Ring 20x3.15 N0282222

Lots of rags and cleaner