4 minutes ago, flybynite said:

Don't see why that it controversial

Perhaps if you didn't make a statement that no-one else I know has ever made, I wouldn't question it.

A long time now since it was 'water'. So to be a bit pedantic.  Coolant. Liquids coolant as in antifreeze summer coolant and rust inhibitor with or without H20.   When there is water the boiling and freezing point is altered by the other stuff present.  Oil also being a coolant with an ICE. 

Edited 29 July, 20214 yr by e-Roottoot

5 minutes ago, KenONeill said:

Perhaps if you didn't make a statement that no-one else I know has ever made, I wouldn't question it.

 

If you read it correctly it may help  "circuit" and "system" mean different things for most people.

 

Modern cars and engines do many things most people have not heard of.

This is my take, feel free to correct any mistakes or misunderstandings I've made

 

I couldn't find anything Europe EA888 Gen 3b specific but I did find "eSelf-Study Program 920243" for NAR EA888 Gen3 engines which is where the below pictures etc are from.

 

In regards to the "oil circuit", ignoring the usual pressure valves, the only obvious change in oil distribution I can see is for piston cooling using 18 and 19:

 

Which are activated as per this schema suggesting it's only for fuel economy rather than decreased warm-up time:

 

The coolant circuit is a completely different beast and that definitely changes flow paths depending on temperature.

 

There are too many modes to explain in detail but as @flybynite mentioned, it does use the "oil cooler in reverse" to warm up the oil:

 

This doesn't mean reversing the oil or coolant flow as @J.R. understood it.

 

Rather that the "oil cooler" heat exchange direction is reversed to normal so it's being used as an "oil heater". The fluid flow direction through the "oil cooler" haven't actually changed, just the function 

Thanks for that, I had always understood that the oil cooler became an oil heater during the warm up phase, I thought that it simply meant that it was functional and in circuit the whole time, it probably was on earlier iterations.

 

VAG have done a good job of balancing conflicting requirements, to get the engine up to temp ASAP whilst having some wrmth from the heater ASAP with a priority of getting the oil up to temperature or at least reducing its cold viscosity before the driver rags the hell out of the engine, all this with a diesel engine with such good thermal efficiency that on a cold day driven sensibly it would struggle to heat the coolant.

 

My Yeti CR TDi warms up really quick compared to its PD predecessor thanks to all that they have done, the price to pay is the achilles heel of the capricious water pump sleeve.

 

But then what do I know? A member of the Trol(l)itariat that needs pictures to understand anything

 

I know when to stop digging a hole I mistakenly started.

Edited 29 July, 20214 yr by J.R.

Top work Langers, as usual. 

Extreme complexity!, wouldn't like to own an old one.