Oil Pressure issues

[Tonks4x4]

Here is the list of recommended Valvoline products for RS2
SynPower XL-III 5W-30
SynPower MST 5W-30
SynPower MXL 5W-30
DuraBlend MXL 5W-40
DuraBlend 10W-40
MaxLife Synthetic 5W-40

And the 15W40 oil spec currently used for running in is

SAE Viscosity Grade 15W-40

Viscosity, mm2/s @ 100 ºC. ASTM D-445 14.8
Viscosity, mm2/s @ 40 ºC. ASTM D-445 110
Viscosity Index ASTM D-2270 138
Viscosity, mPa.s –20ºC. ASTM D-5293 <7000
TBN, mg KOH/g ASTM D-2896 8.5
Pour Point, ºC ASTM D-5950 -36
Specific Gravity @ 15.6°C. ASTM D-4052 0.879
Flash Point, COC, ºC. ASTM D-92 218

[A80Avant]

im hoping to use a 10W40 in winter here in the UK as the temps do not go that high. Also my car idles at about 85C coolant temperature anad a larger oil cooler as well. If it doesnt work, ill go to 10W50 or 5W50

[rs200]

so the I want to have good pressure at idle and good oil.
I lot of oil , but newer 10-50. so you think that will be good?

with 10w-40 you will newer get good oil pressure at idle. I think it is like water. I want to find more compact oil for engine.
could 10-50 be it? we will try.

[A80Avant]

if the amsoil i have (10W40) generates low pressure at warm idle, then i may go back to 10W50 or try 5W50 as the latter has specs somewhere in between the 10W50 and 10W40. The higher the warm grade, the thicker the oil, and therefore pressure should be higher, however i have been looking at oil specs and sometimes you can be amazed as one oil with 10W40 may be very close to another with 5W50 etc.

my whole point is to find the ideal oil to match audi's specs on what the pressure should be on cold and warm temps.

[rs200]

if your engine is fresh rebuilt with all new parts , than it's good to drive it first 1000km on 15w-40.
than after that, you put oil which you want.
before all this "oil pressure problem" I use 10w-40. I just want to test with 15w-40 , because I think that I will get same oil pressure like my friend have on s6 with fresh rebuilt engine.
so is your sugest to use 10-50?

[A80Avant]

on the mineral that my mechanic just used for breaking in the engine, which is 15W40(not 15W50), the warm idle pressure was 1.5bar.

On the fuchs titan that i used normaly before the rebuild it was around 2-2.5bar depending on how hot the engine would get.

however i dont know which type of mineral oil he is using and obviously the fuchs titan being fully synthetic and a better oil, is also much thicker at 85C than the mineral one, which can explain some pressure difference.

I have bought to use as a fully synthetic after the breaking in of the engine the amsoil 10W40, and i just want to be sure that the gauge is reading true, so that the thickness of the oil is actually causing the difference in the pressure, and not something else! I could be having the same 0.5bar loss as mentioned above due to age of the gauge, as on cold start it showed 4.5bar on the mineral oil.

[rs200]

well gauge for oil have 3 contact. 1. and 3. are on electric plate and 2. contact are on gauge. so I clean 1. and 3. contact with fine sand paper.
2. contact you can't clean because they are on bolt..

A80Avant.. you said that with 10w-50 you have 2.2 bar on hot idle? and 15w-50 are much better oil? which one did you use?

[A80Avant]

@ rs200

the rs2 auxiliary gauges come in a triple electronic plaque and not as 3 individual gauges. Which contacts did you clean to retest the gauge? I may have a similar issue, or at least need to check if i have as my mechanic used the break in oil which is a 15W40 mineral one and the warm idle was at 1.5bar, wheras with the 10W50 i was using it was 2.2 to 2.5 bar on the same gauge. Obviously with the thinner oil would expect a difference, but i want to make sure anyway

thanks
vas

[rs200]

yes.. yesterday I change them too , and it was the same .
for now I have to fix out gauge, there must be some cold join.. I know it is..

[Thuppu]

Great that you get the issue sorted out. Also the oil pressure sender can wear out when it gets old, and can give you 0,5 bar too low readings.

[rs200]

today I try to find out where is the problem.. and I saw if I turn the lights ON , pressure drop for 0.5bar .. ha ha ha
than I take instrument closter out. put another one from my second audi 200 20v , and they shoes 1.7-1.9 bar at hot idle..

than I clean contact on oil pressure gauge, so now I had 1.5 bar at idle. I have to check all instrument closter, because I had doubt there is some cold joint.

I will post here if I find something !

big thanks to everyone!
Igor

[MrVain]

Well before i rebuilt my engine i had arount 1 bar of pressure at idle and warm oil.

I have changed turbo, pistons, rods, crank, oil pump, cylinder head.. you can see the whole list here:

http://www.garaget.org/?car=95753

I still have 1 bar at idle. The original presure gage most likley isnt that fine tuned and shows a bit difrent from car to car.

[rs200]

well I hope it is.. they work great . they don't have any strange noise or bad bearings.
they are not new but work great !

[Avantus]

quickly skimmed trough the topic, but is your turbo ok? I was told that a worn turbo could also cause some dropped oilpressure.

[rs200]

here is 2 videos of oil pressure.
1. one is with cold start (outside is 29C)
2. video is few minutes later , with hot engine and oil pressure of 1bar

http://www.youtube.com/watch?v=F9Ge4F5Lpco

http://www.youtube.com/watch?v=6HhPgMvFB0s

thanks

at my home is one s6 AAN engine with same oil and they have good pressure newer under 1.8-1.9 bar. why my car is not like this one????