Ok now that I'm on an actual computer....
Chatting with the engineer, he said that the preferred temp to reach
at the block cooling jackets would be 110F before going and driving hard. He stated that is because cold diesels have the most blowby when cold, the piston rings won't seat correctly. So that's the optimum time where you'll blow the most smoke, and gunk up your VNT/VGT's
I then asked about cold diesels and pulling loads. He said if you're going to pull a partial or full load, get it up to temp, or at least until the thermostat starts warming up first before taking off.
In both cases, he was very specific that
diesels are designed to run at operating temperatures. driving them hard loaded or unloaded cold will result in unnecessary blowby, fuel consumption, and added wear to rotating parts.
Good thing most of us on this forum already follow these rules well.
I also did ask about excessively idling, he said never ever more than an hour, because the rings won't fully seat, cylinder pressure will be lowered enough to where you get incomplete combustions, and get raw fuel running to your turbo, gunking it up, and if you have newer emisions like a Diesel Particulate filter, you'll plug it up, or potentially face plug the Diesel Oxidation Catalyst.
Luckily for us, our precious MKIV's only have EGR (for those who haven't deleted yet)
Fun fact, even some agricultural equipment is starting to be fitted from factory with DPF systems and SCR's. Saw a John Deere tractor here recently that used DEF.
So to sum it all up, I think I'm going to stick with letting my engine run for 30-60 seconds before taking off, and keep it easy on the accelerator until the coolant gauge gets to at least one notch up.
Also, that Chevy diesel was a total joke. Worked on one once. Looked like they were trying to copy the Navistar 7.3 IDI. Similar pump, but ran the other direction.
And our cars and the late 80's/90's Dodge Cummins, about the only thing they had in common was the fact they used a similarly styled fuel injection pump. I wish our cars had gear to gear timing components. Course I'm sure VW didn't want to make an indestructable engine