Oil Leak Turbo 1.9 TD: Causes & Fixes

Hello.
'In my Golf 3 1.9 TD (23,000 km, manufactured in 1992), which has been modified with an intercooler (approximately 105 horsepower, for 10,000 km), oil has been leaking from the turbocharger for some time. Recently, the amount of oil leakage has been increasing, reaching approximately 1 liter per 1,000 km.'
Does the turbo need to be replaced (which is expensive!!!), or is there a possibility to seal or repair it?

Hello!
What kind of oil are you using in your diesel engine? You might want to try using a thicker oil, which would have a higher viscosity number.

Hi.

... namely, when oil leaks out on the suction side and so much of it enters the cylinders with the air that it is sufficient for a "separate" combustion.
Then the idle speed will keep increasing... possibly, the engine might even suddenly surge to dizzying RPMs, and you can only shut it off in time to avoid a motor puzzle .

Hi.
Okay, so my AAZ KKK turbocharger started leaking oil from the large housing seal on the turbocharger side at around 80,000 km. It didn't cause me too many problems.
'For the past 1000 km (now approximately 140,000 km), I've had a cooler from KW-Systems installed. Attached is a boost pressure increase to 0.9 bar, measured at the LDA (likely a sensor). After driving less than 100 km, a loud turbo whistle developed, accompanied by a significant pressure loss. Oil was leaking from the back, and I was the laughingstock of southern Germany.'
I had the turbocharger rebuilt by stk (www.turbocharger.de). However, they reduced the boost pressure. It's really quite extreme, but it's only producing 0.5 bar regulated through the wastegate, despite having a bypass valve from KW-Systems. I haven't had the motivation to readjust it myself yet.
The work done by STK looks good overall. The cost is €370.