SiV6Qcoupe

For those of you who don't know I live with a serious condition (the 12v kind)where I suffer from zero oil pressure on starting the engine after shut down periods exceeding an hour like the pump just will not prime. I've learnt to live with the condition by giving the engine a short blast of revs which brings the pressure up from zero to the full 5 bar. The oil pressure runs perfectly within spec untill the next long shut down.

I've near practically done everything to try and solve the problem including a new oil pump with gaskets, new oil retention valves in the valley pan, new oil pressure valves in the heads and sealed up all joints on the oil pump suction pipe and also thoroughly cleaned the mesh. I've tried all major brands of oil filters and weights of oil.

Anyone know of anything that can cause such a problem?

The problem didn't start overnight but took several months to build up to a every-start occurance.

I know Audi changed the oil pump and relative suction pipe and also moved/incorporated the pressure relief valve and a new 5 bar regulating valve into the upper oil pan in the AFC; looks like a retrofit to the AAH can be achieved with a new pump, pipe, lower oil pan to accomodate the new suction pipe position and pressure valve plate assembly but it's going to be an expensive possible fix but it seems a little coincidental that Audi redesigned these components, like they knew the sort of problem I'm experiencing could be a possibility if they didn't incorporate changes into the V6.

MikTip

Any metal particles found?

SiV6Qcoupe

No, no metal particles were found when an oil change was performed after first realising the problem. What's your line of thought there?

Brdman*

bad sender?

SiV6Qcoupe

Checked out with mechanical pressure gauge too :-(

MikTip

Pressure relief valve by-passing oil?

SiV6Qcoupe

Seems the oil is draining out of the oil pump somewhere between the pump inlet and the oil filter. The filters' anti-drainback valve should hold the oil at that end so I suspect the inlet side. I have a new pump which also has a new relief valve and spring too. It seems the the pump under idle revs doesn't have enough suction to draw oil up through the suction pipe whether this is due to no oil but air in the pipe (should it stay filled with oil during shutdown?) or there is an air leak either externally or internally.

MikTip

Hows the oil pick-up tube? Maybe cracked, or not seated properly?

SiV6Qcoupe

Looks okay, no cracks or holes but the rubber end part that hoses the strainer mesh has gone hard. I tried to seal all all the possible gaps with silicon sealant but the problem still exists so I've just ordered the revised pick-up tube, the original AAH version has been superceeded by this. Have to wait ten days for this, the dealer says it's on back order, a big demand part heh?

fiwis

Hi there from Spain.

I've got an V6 Avant '95 model, and it looks I'm having the very same problem!!!

Just got oil warning after 1 hour trip, for a while, next day for 3 times and end up with fixed warning, always when staritng the engine in cold days.

Took the car to the garage, they clean oil pump and circuit, and changed the oil. Everything was fine, but this morning... same again. Garage just told me pressure it's ok once engine got some, and next it's to change oil pump ($$$$)...

It must be something really stupid, any idea how to sort it and how to deal with in the meantime?

Regards,

Raul