The issue is (and has been) EGR and the effects of premature wear of the piston rings and ring grooves.
I have always advocated the elimination of the EGR system for the above noted reasons.
You're using prime engine oil...and addressing the CCV system is the gateway to helping your engine towards a long and healthy service life (read less expensive operating costs).
What I have seen in many A-4 TDI intake manifolds at 65K+ miles is excessive carbon build-up that restricts air flow into the engine.
The turbo is producing the same amount of boost (PSI) but the actual volume of air entering the combustion chambers is gradually less & less as the intake manifold becomes restricted (clogged)with EGR carbon.
The results are...the more you drive a TDI the more the EGR clogs the intake manifold....the less air is pumped into the combustion chambers...the less effiecient the engine becomes.
Now...throw in more EGR...over a longer period.
The engine is getting less air...more EGR and now the piston rings and ring grooves wear sooner than they should.
In my opinion this engine likely can run a million miles but
I doubt the car would hold up.
Case in point is the diesel Rabbit...many of these engines are still running like clocks (no EGR sys)...but the bodys are scrapmetal.
The first thing I did when I bought my A-3 (new to me) after cleaning the intake ...was the elimination of the EGR and CCV systems.
On your 2k2 Golf @ 48K miles....your engine isn't even fully "broken-in" yet. Basicly your engine is "as new".
Eliminate the EGR system...and your main consern will be maintaining the body and the other systems on the car.
This is why I perfer the GL over the GLS ( I don't buy cars for their resale value). As age take is toll on the car's systems...pwr assessories only become difficault and expensive repairs.
The day I can't roll up a window or lock/un-lock a door...is the day I'll quit driving.
Till that time comes...I perfer to operate windows and latches ...manually.
The same goes for the tranny...and the issues noted on this forum conserning the auto "slush-box" are many...too many.
Ok..I'll get off of my soap box now...
... but I'm wondering if my dreams of a long-lived engine were true, or...just wishful thinking
Not wishful thinking...its the exact reason I am such a strong proponent of the TDI engine.
I perfer long term ownership (15+ yrs) ....low operating costs, great MPG...and good performance...all in the same package.
This is what the TDI has the potential for...eliminating the EGR early in the life of the car is the stepping stone to achiving those goals.