Carlos007

Hi i have an audi 4000s with mc turbo engine.
I seem to have a huge oil pressure problem:
When i start it the pressure is all good 4.5 to 5 bar but as the engine warms up it goes lower and lower and lower... till it reaches .5 .3 bar ouch. at idle speeds i used a thech oil pressure gauge to make sure my vdo was accurate and unfortunaly it is... now to repair the oil pressure problem i tried changing the main bearings and the rod bearings had to change them anyways, i changed the oil pump, i bypassed the oil cooler... none of those helped at all.
What else could be the likely coulprit? I did use a kh oil filter array (two filters) instead of one like the mc has could something inside that be screwed up? Could there be too much oil going to the turbo? I also changed my oil a few times, filters, etc.It's first time i see oil so clean on a dipstick btw, i used 15w40,i once used mobil1 w50 grade but that was expensive for the two weeks i used it..
Anyways any help is greatly apreciated could it be head gasket? head cracked? Im not loosing oil btw either in cyl or in water lifters sound clean...compression is good.

4000skq

just an idea. check that the pressure relief valve in the pump is not sticking, although that would probably not cause a slow drop in pres. I know you said that you changed the pump so probably not very likely. Possibly a pickup tube issue? Since your not lossing oil it must be something mechanical. Im not familiar with the kh oil filter setup. Did you make sure to plasti gague the bearings when you installed them? When i built my NF motor i had a problem with to high of oil pressure, turned out to be a clogged galley that ran oil to the head. Could there be a possiblilty that the oil is pooling somewhere on the top end of the motor and not draining into the oil pan fast enough? Just some ideas i had, just ideas.

Carlos007

I checked the oil pressure relief valve a while ago, actually switched the bolt to an oil temp gauge and added a few washers (inside) to be sure spring had enough tension...I didn't however use plastigauge it didn't seem that it was needed...Crank looked pretty nice however i might do it now that you mention it, can't hurt...
I have put a new gasket on the oil sucker and the screen looked ok i did clean it just to be sure.
Oil does'nt stay on top since id probably have oil coming out of the valve cover or something.
Any ideas are cool since this is a mystery...
Also all oil sprayers are well secured.
I might check on ebay for an mc filter thingny if anybody has a good one for sale?
I might just disassemble the motor completly this week or the next. maybe the oil is going directly back to the botom thru the headgasket?
or head is cacked?

Carlos007

yea well my engine is dead some main bearings are all used up .... dammit i need a new bottom end: block crank and flywheel anyone from canada with good prices?