Where did you learn that the 3.0L has tighter tolerances than the 4.0L? I doubt it.

 

I didn’t say that. What I did say is that 20, not 40 weight, is the spec for the 3.0L/C20.

 

1/ Okay, apart from reading sometimes the owner's manual I have been involved in motorsports for many years. So I still remember a bit about how the engine is built and what oils are used for different engines.

2/ The OP's car is a car from the German market so it has OPF.

3/ I still believe that oils are selected to the engine specification and this should not be changed. As you would have probably noticed, 0W40 oil with the C40 standard is recommended for Porsche V8 engines in specification for the S, GTS and Turbo models, but a different C40 GT 0W40 oil is recommended for other Porsche models in the GT version. This is also clearly stated that C40 GT can't be used for engines with C40 specification. So despite both being 0W40 oils, they are definitely different and cannot be replaced. Also, C20 and C40, apart from different viscosity, are different oils for different engines.

 

@Poppyboy i think people are referring to your post #11 where you said "it is also due to tighter tolerances".

 

You wrote this: “While some of the rationale for 20 is for fuel economy, it is also due to tighter tolerances.”

I asked where did you learn that? You then denied writing it. I am confused. Do you have any support for what you wrote?

 

I don’t need to waste my time citing sources for you. I’m letting the OP know that 20 weight is recommended for the 3.0L instead of 40 for a reason. If you don’t believe me, I could really care less.

 

@Poppyboy i was genuinely curious what you had heard because i have listened to a decent amt. of naptowntuner on youtube and he is an audi internal engine guy. some of the things i have picked up are that the thinner oil can more easily penetrate so my assumption was that it warms up quicker and moves into the crevices more quickly.

 

That is definitely true in some circumstances. When your not mechanically inclined such as myself, I dont really have any option as im sure many are not able to do the work on these cars that alot of the posters can do. I think its all relative. I have a skill set that im sure you would pay for that I think is silly to pay me to do, but im sure you do pay for it.
Dealership will be doing all the work under warranty, and then ill use an Indie for everything else.

 

Sorry if my response was punchy. I have read and learned over the years that tolerances have become tighter and tighter. I’m not suggesting that tolerances are any tighter across engines. Unless oil is being consumed via faulty rings, bore scoring, etc, using 40 weight may put additional strain on an engine engineered for 20. I can only surmise that 40 weight for better heat management given the additional turbo of the 4.0L. But then again, I’ve read that the quicker flow of 20 weight would better accomplish that.

 

I recall you had mentioned that. What I wonder is, with our EA839, is the only oil pressure regulation the adjustable vane oil pump itself (getting feedback from the pressure sensor for regulation), or is there a spring and ball type bypass somewhere too? Otherwise, full pressure at colder temps at startup cold be quite high, and unregulated because the solenoid to the vane pump was disconnected.

In a hybrid application, where the cold engine can be brought online in a high output demand situation, pressures could be quite high, and if using, say, a C40 weight oil, possibly 100 psi ?

When I used to mess with 60s and 70s Chevy and Ford engines, there was a thing called bearing washout, where pressures were deemed detrimental once over 60-70 psi. Partially due to so much oil flying off the rod bearings at speed that oil was foaming more, even with windage trays of the day.

I know there are tunes available for these engines to increase power. I wonder if these tunes override the factory oil pressure map in the ECU, ie adding 10 pounds across the board ?

 

As a curiosity, I will add that in new Toyotas known for their reliability, 0W8 oil is used. Each oil is adapted to the engine design and even to the materials used in these engines.