Audi A6 C5 1.9TDI intermittent oil pressure problem

[purru]

Hi,
it all started back in February of 2023 when I first got my low oil pressure warning on the dashboard. I immediately turned the engine off and checked the oil level, on start up listened to strange noises but could not hear nothing concerning.
The low oil pressure warning continued to show up when the engine was still warning up (temp might have been around 70 degrees celcius) once every two days or so until the spring came, then it even got more rarer and when summer came it didn't show up at all. The last outside temp that the error show up was +10 celcius outside temp. It isn't logical that during winter when oil is thicker i have low oil pressure and during summer I had no problem with low oil pressure.
I have tested many oil pressure sensors, even the original one from Audi, all have failed after 2 days. Also tested the oil pressure from engine which was also OK. The engine doesn't seem to be leaking oil also. Only thing is that my intercooler pipe comes a little loose and spits a little oil to the coolant tank, but I think this isn't related with my problem.
The milage is around 249k miles, the problem started around 239k miles.

Any ideas to fix this anomaly?

 

[purru]

I should also add that it usually beeps and flashes 3 times, then goes away for a short time, then comes back and beeps and flashes again 3 times and then goes away. Some day it it does more than a couple of times, then i restart the car and the problem does not occur anymore until the car sits for maybe at least 5 hours until it cools down.

 

[jack88]

I have this same issue on mine AVG code . Similar milage. Just replaced oil pump and it didn't cure the problem. Also have been through several pressure sensor. No joy. Did you fixed your problem?

 

[purru]

Hey, I still have this issue, although when I took a look at pressure relief valve and sanded it smooth, because it was kind of stuck there, the problem was gone for two weeks and then came back. The next thing to do is to replace oil filter housing and see if the problem goes away.

 

[jack88]

This was my other thoughts about housing. I just measured oil pressure and it is like a book said. Where is oil pressure relief valve on this? Filter housing?

 

[purru]

Yes, it is in the filter housing, there are pictures online where it is

 

[jack88]

Do I need to take the housing off or just the filter? I'm on it at this moment

 

[purru]

You need to take the housing off

 

[jack88]

Thanks for your help. You are probably right about this. Now when I'm thinking of it it becomes bit tapping like hydrolic lifters lack of oil when it's hot. Meaning that the crank is well lubricated but the top isn't. I had the sump off yesterday to do pump and everything looks like new inside. I'll take the housing today and update you later.

 

[jack88]

Took it off and I can't see any valves. Don't know if we are talking about the same engine

 

[purru]

This is how the housing looks on my car. AWX engine

Oil filter Oil filter bracket Oil cooler 1.9ltr. 96KW for Audi A6/Avant (A6) 2002 EUROPA | 7zap OEM Catalogs for Finding Auto Parts by VIN and Parameters

oil filter Oil filter bracket Oil cooler 1.9ltr. 96KW for Audi A6/Avant (A6) 2002 EUROPA

audi.7zap.com

 

[jack88]

Ah completely different then mine. Mine is AVG with metal filter. Put it back together now with new sensor. Will see if it cure it