Low oil pressure

[twoqu]

If we discount the steering from the equation then we are left with a few ideas.
Apart from the viscosity, the only other tempearture dependent item in the oil system would be the thermostat built into the oil filter housing. Not sure how you can verify that without just feeling the pipes.
You have also disturbed the large temp sender which has the non return valve installed behind it. I am not sure what happens if that malfunctions or whether it could fail in a temperature dependent way. I know it largely to prevent drain back from the head but presumably the pump needs to work against it.
To be honest can't see what what cause the issue with the car just sitting. There has been a case recently of the oil pump drive loosing but that engine was subjected to excessive abuse far beyond normal operating conditions!

[Barn]

Sadly I may have to sell, I'm running out of money. So far I have purchased new oil pressure switches, oil lntake manifold, oil pump, steering rack, power steering pump, both track rods, track rod ends, steering damper, clutch flexi hose, thermostat, all wheel nuts and more.
I started with the oil pressure switches due to the fact that one was leaking, after replacing the switches the car was fine so I started on the steering overhaul. I was then aiming on going through the various mounts and bushes, I already have black power flex front subframe bushes and front lower arm bushes.
I obviously would not have carried on with the overhaul if I new the oil pressure was going to be a problem. I have invested nearly £1500 just in the steering which could have gone into my now more serious problem.
One thing I did notice today was when the car got hot and the low pressure warning sounded only one pipe going to the oil cooler was hot the other one was almost cold ?
The valve behind the pressure sender seems to work as the top end doesn't ever rattle on start up, so I take it oil is not running back.

[twoqu]

Without any airflow you would expect that the return would be almost as hot as the supply. Not sure if thats implying some sort of blockage in either the cooler itself or the return pipe. The question is whether that would explain the symptoms. Obviously once the stat opens it does divert a certain amount of oil so perhaps if that is not being returned the level drops.
Just late night ramblings. Wish I had the definitive answer for you.

[Barn]

I thought it was a bit strange that they weren't both hot, perhaps I could loop the cooler out of the system ?
Thanks for the input.

[twoqu]

I thought it was a bit strange that they weren't both hot, perhaps I could loop the cooler out of the system ?
Thanks for the input.

Although if its the return side that needs to open for the flow to start that would explain that! Need to look at how exactly it works. Having said that if the temperature is enough you would expect both pipes to be hot.
Just trying to link the hot pressure drop with something. Would have thought the oil pump drive would struggle with cold oil rather than hot but who knows!

[twoqu]

http://www.s2forum.com/forum/showpost.php?p=775501&postcount=5

[Barn]

I had a water temp of 90 when I ran the car today so I would have thought both oil pipes should have been hot.

[twoqu]

The oil stat is only concerned with oil temp! I have seen a temp of 100C mentioned by one member who tested it with boiling water. So thats oil temp of 100C. So perhaps it just that it hasn't opened.
Annoyingly there is a stripped down oil stat post/thread somewhere on here.

[Barn]

I guess the oil wasn't hot enough. I will keep searching for an answer, the car runs so smooth and quite, also the engine internals are really clean, hopefully it won't need a major rebuild my wallet can't stretch to that.

[Bowie69]

This one.... http://www.s2forum.com/forum/showthr...t=69194&page=3

[Bowie69]

Is the oil pressure gauge you used a known-accurate one?

[Barn]

I used my snap on one,it's always been fine.

[twoqu]

Not much help, but perhaps this at least allows us to understand the oil system a little better. You wil have to ignore the extra oil filter which Audi used on earlier models for the turbo. It was the only diagram I could find. You should be able to see how the piston covers/uncovers the port. Still struggling to see how this would cause your symptoms even if it malfunctioned unless it is stuck shut and oil temperature is high enough to effect things. Although that should have been observable.

[Barn]

Thanks for the diagram. I don't think the oil got hot enough in the engine and I agree that I do not think this is going to be causing the problem.
I have ordered the oil pump drive lever today the part that is heated on to the crank and drives the pump, when I checked it felt very solid but it may be coming loose when the temperature rises. I am really clutching at straws now.
The other thing I noticed is that when the pressure drops as it gets hotter, if you increase the revs the pressure still does not increase so the drive lever may be slipping on the crank !

[Az786]

Where about are you located pal?