Oil pressure TOO LOW on AAN

[FabS6]

Hello mates,

My mate in Germany is having seriou problems with his S4 C4.
Some time ago after pushing the engine winning over an E46 M3 on the autobahn (stock engine and turbo, upgraded ECU, 1.7 bar of boost on the K24-7000) he started to have problems.

- Oil pressure alarm --> spun conrod/main bearings --> new conrod/main bearings

Then after using the car and downgrade the ecu to stock power levels he felt the car with no power at all, less than when stock 230bhp. Then, problems again:

- Oil pressure alarm again --> changed oil pressure sender (the gauge sender)

- Once and again... low pressurewhen driving, this time: new oil pump!

He got the car today again and the oil pressure stills under 1bar at idle (warm engine) and 2 bar at cold idle.

I talk to him by phone and did bring the cellphone near the oil sump with the engine at idle(warm) and there was a constant WEIRD noise... like a zzzzzzzzzzzzzzzz...coming from the sump.


Has anybody experienced a problem like this? Does anybody have an idea what could it be? Main bearings failure again? I don't know how to help him anymore guys.
Hope some of you could help us!

Thank you all in advance!!

[V6quattro]

Last week i had a oil pressure problem on a 5 cylinder diesel. Took the oil pump of and found this. So did you check the bolts on the new pump?

[mike74]

Blocked oil pick up in sump maybe?

[FabS6]

Last week i had a oil pressure problem on a 5 cylinder diesel. Took the oil pump of and found this. So did you check the bolts on the new pump?

THank you for your kind reply mate!

I forwarded the picture to my mate and though about this or maybe a bearing damage again. If it is a bearing failure I could start thinking it is a damaged cranckshaft that is runing the new bearings again.

He is desperate now almost out of money because all this problems

[FabS6]

You think mate? I'll ask him to unbolt his sump and clean it or check it if blocked or not!

Thank you mate!!! really!!

[FabS6]

Blocked oil pick up in sump maybe?

You think mate? I'll ask him to unbolt his sump and clean it or check it if blocked or not!

Thank you mate!!! really!!

[K Simmonds]

On another point altogether 1.7 bar on the stock K24 is beyond brave and well into silly territory, surely it's just going to be blowing hot air at that sort of boost level? I strongly doubt that has anything to do with your friends crank and oil pump problems though, I'd looking at the pump itself along with the pick up first.

[popdemonic]

Has your friend checked the clearance on the crankshaft journals with plastigauge?
if it spun the rods i doubt it would need some grinding job on the journals and undersized
bearings.

[UrS4boy]

....He got the car today again and the oil pressure stills under 1bar at idle (warm engine) and 2 bar at cold idle.

You don't mention what weight oil is in the engine. Should be 10W40 at least and with the summer heat, more like 20W50 (in my opinion).

[Zoig]

Have you replaced the one way valve that resides just before the oli pressure sensors. Also are you only relying on electronic sensors or have you veryfied the results with proper manometer?
Oli filter must be OEM!

Last year i had some problems after engine rebuild, did not get any notceable oil pressure. The one way valve had collapsed (reason unknown still) and oli filter was cheapest c**p avaliable. After changing both of them i got solild 2.0Bar idle and 7.5Bar on hingher rpm. Tried with worn and relatively new oil pump (both werte measured over) and the difference was marginal. I did plastigauge the tolerances but i cant remember how small they were. Mostly on the large side of factory tolerances if i remember correctly.

[FabS6]

On another point altogether 1.7 bar on the stock K24 is beyond brave and well into silly territory, surely it's just going to be blowing hot air at that sort of boost level? I strongly doubt that has anything to do with your friends crank and oil pump problems though, I'd looking at the pump itself along with the pick up first.

Yes mate, I know 1,7 is pretty out for a good efficiency of the K24 and also told him about that, too much hot air in the engine, that is why he downgraded the ecu to stock specs. I run 1.45bar and also ported the compressor side by myself (not too much) to avoid overheating the compressed air too much. I told him to check the sump pick up asap.

Thanks for your answer mate!

[FabS6]

Has your friend checked the clearance on the crankshaft journals with plastigauge?
if it spun the rods i doubt it would need some grinding job on the journals and undersized
bearings.

Indeed mate!! I realized of that a few days ago... he spun the bearings and changed them but... I THINK he didn't measured or checked the crankshaft for damages. Possibly the problem is there! But no idea if he checked the clearances or not.

You don't mention what weight oil is in the engine. Should be 10W40 at least and with the summer heat, more like 20W50 (in my opinion).

I asked him about that mate, he uses the 5w30 one. I use instead the Edge 10w60 and it is fantastic!

Have you replaced the one way valve that resides just before the oli pressure sensors. Also are you only relying on electronic sensors or have you veryfied the results with proper manometer?
Oli filter must be OEM!
Last year i had some problems after engine rebuild, did not get any notceable oil pressure. The one way valve had collapsed (reason unknown still) and oli filter was cheapest c**p avaliable. After changing both of them i got solild 2.0Bar idle and 7.5Bar on hingher rpm. Tried with worn and relatively new oil pump (both werte measured over) and the difference was marginal. I did plastigauge the tolerances but i cant remember how small they were. Mostly on the large side of factory tolerances if i remember correctly.

I told him about the oil filter too...some filters which bolts perfectly to the engine but aren't the indicated ones for them, may have some pressure limiters inside and if he doesn't use the correct one, that could be the cause. But dunno about the one-way valves mate!


P.S.:
Thank you for all your kind answers, mates!!! Good to know there is kind people out there!
I will let my friend know about all these answers!!!

[Zoig]

Do check the one way valve if possible, it's malfunction will show low pressure at the gauges while i'ts fine at the bottom end. Problem is that the head is not getting enough oli if it's fautly.

[pasbogdan]

Indeed mate!! I realized of that a few days ago... he spun the bearings and changed them but... I THINK he didn't measured or checked the crankshaft for damages. Possibly the problem is there! But no idea if he checked the clearances or not.
I asked him about that mate, he uses the 5w30 one. I use instead the Edge 10w60 and it is fantastic!

The crank that suffered from a spun bearing needs regrinding to -0.25 mm
And all engine needs flushing and cleaning of all bearing pieces in all oil passages.If not oil will get that parts again at bearings/oil pump and damage again.
10w60 is to thick,sometimes even in summer times for a street car,that is used many times with cold starts.