If you're talking about valve ticking at cold start-up, that is normal if you haven't driven the car in a while. If it happens regularly, your hydraulic lifters have issues.
Not talking about cold start valve tick. I said it made a collapsed valve lifter
sound, but clearly stated it came from VANOS unit. I used a medical stethoscope to confirm it, and I could also feel it.
upon further thought, regarding the VANOS issue, losing pressure using thinner oils doesn't make any sense.
On a separate note, the double VANOS unit has a known problem with the seals wearing out sooner than expected. If the seals are worn, and you use a thinner oil, it is possible that the thinner oil is leaking through the worn seal causing lost pressure. The problem in this case is not the oil, but the worn seal.
You just proved my point, thank you. From your statement above, you do agree that thinner oil can cause the noise, due to lower pressure - in your example, due to a bad seal.
3. if you try to pump water vs vegetable oil through the tube to inflate the balloon, what do you think is going to inflate the balloon faster? Answer: the water (thinner oil).
The reason the balloon fills up faster with water is because it takes LESS pressure to move a low viscosity liquid, hence a higher volume is moved in a given period of time. You've actually given a good example of why thinner oils require and provide lower, not higher, pressure in a thermodynamic system.
Everyday proof: Watch the oil pressure gage in a car. When the oil is cold and thick, the pressure is high. When the car warms up, the pressure drops.
I don't know who the "I, and many others.." you are referring to are...
The "I" is me. I am speaking from PERSONAL experience. I tried M1 5w-30 and the VANOS unit in my 94 and my 99 got noisy after warm up. I confirmed it with a stethoscope, and I could feel the tap. I changed it to 10w-40 and the noise went away after about 2 days.
If it was a leaky seal, the noise would likely have gone away sooner - as soon as the fresh oil flowed. I believe that it was a hydraulic issue in the VANOS assembly. There is a reserve of oil in the unit, similar to a hydraulic valve lifter, and it takes time for that oil to exchange.
The "others" are easily found with a Google search. I read several other automotive related forums, and this exact same issue has been discussed at length by Toyota Tundra owners, GM LS1 owners, and Suburu WRX owners, to name just a few. M3 & non M3 owners also have discussed this at length on autocross and track forums that I visit. Here is yet another BMW thread:
Many people do not realize this but vanos is COMPLETELY run on oil pressure alone. If you do not have the proper oil pressure you have no vanos. Imagine the vanos system as a dual oil path way maze. one oil pathway is for when vanos is not engauged, the 2nd is when the vanos is supposed to be engauged. the thing that shifts between the oil passages IS the vanos solenoid, thatts why it is such an essential part of vanos. without it you have no vanos. if the solenoid does not operate 100% vanos will not work properly. Lets say the vanos only has enough force to push change the machanism that changes the oil pathway 50%, well that means only 50% of oil will get into the "vanos on" pathway and thereby reducing pressure greatly which will then in turn only move change the cam timing by 6 degrees (instead of the full 12 as it is supposed to in the mid range).
Another factor that is essential is the oil ITSELF. it is the mechanism by which u push the vanos gears. If you use a really thin oil (aka mobile 1), it flows like water and it does not have the same oil pressure as a much heavier 15w-50 weight oil which is much thicker (think of molasis). the 15w-50 is able to "push" the vanos to the proper specs better b/c it has higher compression & oil pressure characteristics and is much thicker. so your oil is just a crucial aspect as the solenoid or vanos mechanism itself. Thats why you see so many people say "i replaced my vanos but the noise came back!" well duh! u are using the wrong oil or your solenoid is bad.
So basically... if you are have vanos problems here is the order you should replace things...
1) change to a much thicker oil (preferably a 5w40-20w-50, bmw recommends 20w-50 for a reason, but you can do castrol 5w-50 which will work in pretty much every weather condition & bmw recommend castrol anyways).
2) change vanos solenoid
3) then replace vanos unit if necessary (though I have spoken to NUMEROUS BMW master techs and every single one dispelled the "vanos stuck" myth. it simply cannot happen they say, jus thought i'd share that).
Different brands of oils of the same grade vary in their specs, and Mobil 1 is thinner/less resistant to shear as evidenced by CentiStoke analysis. Mobil 1 falls at the low end of the specs for the 5w-30 standard:
Mobil 1 SAE 5w-30:
Viscosity, cSt @ 40°C: 53.0
Viscosity, cSt @ 100°C: 9.9
Viscosity Index: 162
Pennzoil Synthetic with Pennzane SAE 5w-30:
Viscosity, cSt @ 40°C: 57.4
Viscosity, cSt @ 100°C: 9.87
Viscosity Index: 159
Quaker State Full Synthetic SAE 5w-30:
Viscosity, cSt @ 40°C: 62.05
Viscosity, cSt @ 100°C: 10.17
Viscosity Index: 151
Royal Purple SAE 5w-30:
Viscosity, cSt @ 40°C: 62.5
Viscosity, cSt @ 100°C: 10.5
Viscosity Index: 160
Redline SAE 5w-30:
Viscosity, cSt @ 40°C: 65.0
Viscosity, cSt @ 100°C: 10.6
Viscosity Index: 153
AMSOIL SAE 5w-30:
Viscosity, cSt @ 40°C: 63.4
Viscosity, cSt @ 100°C: 11.7
Viscosity Index: 182
The bottom line is if it works for you, great, It didn't work for me, and I will not use it, and I will not bother to try M1 0w or 5w in my 330. And if someone asks for a recommendation, I will tell them.